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Crestal bone loss around submerged and nonsubmerged dental implants: A systematic review
SYSTEMATIC REVIEW
Crestal bone loss around submerged and nonsubmerged dental implants: A systematic review Mohammad D. Al Amri, BDS, MS, FRCDC A variety of factors have been ABSTRACT associated with crestal bone Statement of problem. To my knowledge, there is no systematic review of crestal bone loss (CBL) loss (CBL) around dental imaround submerged and nonsubmerged dental implants. plants, including periodontal Purpose. The purpose of this review was to systematically assess CBL around submerged and biotype,1,2 bone density and nonsubmerged dental implants. the formation of biological Material and methods. The addressed focused question was, “Does crestal and subcrestal width,3 implant placement placement of dental implants influence crestal bone levels?” Databases were searched from 1986 4 5 depth, interimplant distance, through October 2015 using different combinations of the following keywords: crestal, sub-crestal, implant microdesign and bone loss, dental implant, submerged, and nonsubmerged. Reference lists of potentially relevant macrodesign,6,7 occlusal overoriginal and review articles were hand-searched to identify any further studies. Letters to the loading,8 and surgical trauma.9 editor, case reports, commentaries, studies on platform-switched implants, and studies published The early loss of crestal bone in languages other than English were excluded. facilitates the stagnation and Results. In total, 13 studies (6 human and 7 animal), which were performed at universities, were proliferation of anaerobic bacincluded. In the human studies, the number of participants ranged from 8 to 84 individuals. The teria on exposed implant follow-up period ranged from 1 to 5 years. CBL at the test sites ranged from 0.17 mm to 0.9 mm and surfaces, which if left unconat control sites from 0.02 mm to 1.4 mm. Five human studies reported no significant difference in CBL around implants placed at the test and control sites. All animal studies were performed in dogs trolled or untreated may result with a mean age ranging from 1 to approximately 2 years. The follow-up period ranged from 2 to 6 in the further loss of periimmonths. Four animal studies reported no significant difference in CBL around submerged and 10,11 plant bone. However, acnonsubmerged implants. 12 cording to Albrektsson et al, Conclusion. No significant difference in CBL was found around submerged and nonsubmerged an annual 0.1 to 0.2 mm of dental implants. (J Prosthet Dent 2016;115:564-570) CBL after implant loading is a normal phenomenon that occurs as a result of crestal bone remodeling. In this regard, reference to the alveolar crest) influences marginal bone controlling CBL is essential for the long-term success and resorption, and placing them in a submerged position survival of implants. aids in obtaining an ideal emergence profile in esthetic No one definitive therapeutic strategy is most areas.17 One explanation is that placement of the 13 effective in minimizing CBL around implants ; howimplant-abutment interface in a submerged position ever, protocols that have been proposed to minimize the contributes to the maintenance of mucosa texture and loss of crestal bone include the use of platform switched tonality and also favors the reestablishment of favorable implants, using a flapless surgical technique, and marginal tissue architecture as compared with implants placing dental implants approximately 2 mm below the placed at the level of the alveolar crest (nonsubmerged/ alveolar crest (submerged/subcrestal placement).14-16 crestal implants).18 In addition, studies have shown that Placing implants in the vertical dimension (with implants placed in a nonsubmerged position undergo
Associate Professor and Consultant, Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
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significantly more crestal bone loss than implants placed in a submerged position.19-21 Although placing implants in a submerged position would compensate for crestal bone remodeling and improve bone-to-implant contact in the implant neck region, controversial results have also been reported.22-28 In a prospective split-mouth randomized controlled clinical trial, 18 implants were submerged in bone and 18 were placed in a nonsubmerged position in 20 participants.23 After 24 months of follow-up, the radiographic assessment of periimplant bone showed a statistically significant difference in CBL around the submerged and nonsubmerged implants.23 Similar results were reported in a retrospective study in which 342 submerged and 146 nonsubmerged implants were placed in 191 patients and radiographically assessed after 10 years of followup.26 However, according to indexed publications, a systematic review of crestal bone loss (CBL) around submerged and nonsubmerged dental implants has not yet been performed. With this background, the purpose of the present review was to systematically assess CBL around submerged and nonsubmerged dental implants. MATERIAL AND METHODS Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a specific question was constructed according to the Participants, Interventions, Control, Outcomes (PICO) principle (Fig. 1).29 The addressed focused question was “Does crestal and subcrestal placement of dental implants influence crestal bone levels?” P – Participants: Participants must have undergone dental implant treatment. I – Types of interventions: The intervention of interest was the placement of implants using the submerged technique (ST). C – Control intervention: Implants were placed using non-ST. O – Outcome measures: CBL around implants placed using ST and non-ST. The inclusion criteria were as follows: original studies; human (clinical) studies; studies based on animal models (experimental); inclusion of a control group; and intervention: CBL around submerged and nonsubmerged dental implants. Letters to the editor, case reports, case Al Amri
Screening
0 records identified through manual search
13 records selected after duplicates removed
Eligibility
The currently available evidence shows no significant difference in crestal bone loss around submerged and nonsubmerged dental implants.
32 records identified through electronic searches
13 full-text articles assessed for eligibility
Included
Clinical Implications
565
Identification
May 2016
13 studies included in the systematic review
19 excluded after screening titles and abstracts Studies which did not answer the focused question: 10 Studies in which platform switched implants were used: 7 Review articles: 2
Figure 1. Article selection flowchart.
series, commentaries, historical review, and articles published in languages other than English were excluded. In an attempt to identify studies pertinent to the PICO question, the following databases were electronically searched for available data: PubMed/MEDLINE (OVID), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Web of Knowledge, Cumulative Index to Nursing and Allied Health Literature, and Google-Scholar. These databases were searched from 1986 through October 2015 using different combinations of the following keywords: crestal, sub-crestal, bone loss, dental implant, submerged, and nonsubmerged. Titles and abstracts of studies identified using the described protocol were screened. Full texts of studies judged by title and abstract to be relevant were read and evaluated in accordance with the following eligibility criteria: clinical and experimental studies, assessment of periimplant clinical parameters, and CBL around submerged and nonsubmerged dental implants. Reference lists of potentially relevant original and review articles were hand searched to identify any further studies. Articles available online in electronic form ahead of print were considered eligible for inclusion. Letters to the editor, case reports, commentaries, and studies published in languages other than English were not sought. Moreover, studies on platform-switched implants were also excluded because platform-switching has been reported to influence periimplant bone levels.14 The pattern of the present systematic review was customized mainly to summarize the relevant data. Excluded studies and reasons for exclusion are listed in the Supplemental Material. The Newcastle-Ottawa scale (NOS) was used to grade the methodological quality of each study assessed in the present systematic review.30 This scale uses a systematic approach based on 3 specific criteria: selection (S), comparability (C), and exposure (E). These are subdivided into 9 criteria: S1, adequate case definition; S2, representativeness of the cases; S3, selection of THE JOURNAL OF PROSTHETIC DENTISTRY
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Table 1. Characteristics of studies included
Reference
Study Design
Randomized Controlled Trial
No. of Implants (n)
No. of Participants (n)
Mean Age (y)
Study Groups (n = no. of implants)
Follow-up
Bone Loss (Test Sites)
Bone Loss (Control Sites)
Significant Difference
Human Studies Cecchinato et al24
Prospective
Yes
324
84
51.6
Group-1: submerged implants (n=NA) Group-2: nonsubmerged implants (n=NA)
2y
0.17 mm
0.02 mm
No
Carrdelli et al22
Prospective Split-mouth
No
16
8
>21*
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
3y
0.25 mm
0.25 mm
No
Nemli et al23
Prospective Split-mouth
Yes
36
20
38.4
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2y
0.68 mm
0.57 mm
Yes
Cecchinato et al28
Prospective
Yes
324
84
NA
Test site: submerged implants (n=153) Control site: nonsubmerged implants (n=171)
5y
0.17 mm
0.02 mm
No
Ericsson et al25
Prospective Split-mouth
No
61
11 patients
NA
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
5y
1.5 mm
1.4 mm
No
Koh et al27
Prospective
Yes
20
20 patients
55.5
Group-1: submerged implants (n=10) Group-2: nonsubmerged implants (n=10)
1y
0.9 mm
1.4 mm
No
Calvo-Guirado et al16
Prospective Split-mouth
Yes
48
6 dogs
1
Test site: submerged implants (n=24) Control site: Nonsubmerged implants (n=24)
4 mo
0.91 mm
1.89 mm
Yes
Calvo-Guirado et al19
Prospective Split-mouth
Yes
48
6 dogs
1
Test site: submerged implants (n=24) Control site: nonsubmerged implants (n=24)
3 mo
0.93 mm
0.95 mm
No
Negri et al21
Prospective Split-mouth
Yes
36
6 dogs
1
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2 mo
2.05
1.75
Yes
Cesaretti et al31
Prospective
No
25
6 dogs
1
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
2 mo
1.4 mm
2.2 mm
Yes
Hermann et al32
Prospective
Yes
59
5 dogs
w2
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
6 mo
1.68 mm
1.57 mm
No
Animal Studies
(continued on next page)
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Table 1. (continued) Characteristics of studies included Randomized Controlled Trial
No. of Implants (n)
No. of Participants (n)
Mean Age (y)
Study Groups (n = no. of implants)
Follow-up
Bone Loss (Test Sites)
Bone Loss (Control Sites)
Significant Difference
Reference
Study Design
Fiorellini et al33
Prospective Split-mouth
Yes
38
6 dogs
1.5
Test site: submerged implants (n=19) Control site: nonsubmerged implants (n=19)
4.5 mo
0.92 mm
0.99 mm
No
Negri et al34
Prospective Split-mouth
Yes
36
6 dogs
1
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2 mo
0.67 mm
0.62 mm
No
*The exact age was not reported.
control; S4, definition of control; C1, comparability of cases; C2, controls on the basis of the analysis; E1, ascertainment of exposure; E2, same method of ascertainment for cases and controls; E3, nonresponse rate. Each criterion was given a response of “Yes,” “No,” or ‘‘cannot tell.’’ Maximum possible score for each study was 9. RESULTS In total, 13 studies16,19,21-25,27,28,31-34 (6 human22-25,27,28 and 7 animal16,19,21,31-34), which were performed at universities, were included. All human studies included22-25,27,28 were prospective, and 4 studies23,24,27,28 were randomized controlled trials (RCTs). The number of participants ranged from 8 to 84 individuals. Four studies22-24,27 reported the mean age of the participants, which ranged from older than 21 to 55.5 years. Three studies23,27,28 reported the numbers of implants placed in crestal (control sites) and subcrestal (test sites) positions, which ranged from 18 to 171 implants. The follow-up period ranged from 1 to 5 years.22-25,27,28 CBL at the test sites ranged from 0.17 to 0.9 mm and at control sites from 0.02 to 1.4 mm. Five22,24,27,28 of the 6 studies22-25,27,28 reported no significant difference in CBL around implants placed at the test and control sites. In the study by Nemli et al,23 CBL was significantly higher at the test sites than at the control sites (Table 1). However, the remaining studies included16,19,21,31-34 were prospective and were performed in dogs (range: 5 to 6 dogs), with a mean age from 1 to about 2 years. Five studies16,19,21,32,33 had a split-mouth design. The number of implants placed in the participants ranged from 25 to 59 implants.16,19,21,31-34 Six studies16,19,21,32-34 were RCTs. Five studies16,19,21,33,34 reported the numbers of implants placed in the test and control sites, which ranged from 18 to 24 implants. The follow-up period ranged from 2 to 6 months. CBL at the test sites ranged from 0.92 to 2.05 mm and at the control sites from 0.62 to 2.2 mm. Three studies16,21,31 reported a statistically significant difference in CBL around implants placed in the test and control Al Amri
sites. In the studies by Cesaretti et al31 and CalvoGuirado et al,16 CBL was significantly higher in the control sites than test sites, whereas, in the study by Negri et al,21 CBL was higher around the test sites than the control sites (Table 1). Three studies22-24 reported the healing period after implant placement, which ranged from 1.5 to 9 months. Two studies23,24 reported the length of the implants used, which ranged from 10 to 12 mm. Implant diameters, which ranged from 3.2 to 5.5 mm, were reported in 3 studies.22-24 In 4 studies,23,24,27,28 tapered implants were used, while in 2 studies22,25 implant shape was not reported. In 1 study,25 implant dimensions and surface characteristics were not reported. In the study by Ericsson et al,25 submerged and nonsubmerged implants were placed in the mandible, and in the study by Koh et al,27 submerged and nonsubmerged implants were placed in the maxilla. In 2 studies,22,23 jaw location was not reported. In 6 studies,22-24,26-28 moderately rough-surfaced tapered threaded implants were used. In 1 study,25 implant surface characteristics were not reported. In the study by Cardelli et al,22 the interimplant distance was reported, and Nemli et al23 reported the implant insertion torque. In 5 studies,22-25,28 implants were loaded, and the loading time ranged from 2 weeks to 12 months after placement (Table 2). In all animal studies,16,19,21,31-34 the implants were placed in the mandible and had moderately rough surfaces. Six studies16,21,31-34 reported the healing period after implant placement, which ranged from 2 to 6 months. Six studies16,19,21,32-34 reported the length (6.5 to 10 mm) and diameter (2.5 to 4 mm) of the implants used. In four studies,16,19,21,31 tapered implants were used, and in 2 studies32,33 parallel-walled implants were placed using submerged and nonsubmerged techniques. In 1 study,34 both tapered and parallelwalled implants were placed using submerged and nonsubmerged techniques. None of the studies reported interimplant distances and implant insertion torques. In 1 study,33 although implants were loaded, the time of loading (immediate or delayed) was not THE JOURNAL OF PROSTHETIC DENTISTRY
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Table 2. Implant-related characteristics of studies included Implant Length (mm)
Implant Diameter (mm)
3 to 6 mo
w12
3.5 and 4
1.5 to 2 mo
NA
3.4, 3.8, 4.5 and 5.5
3 to 4 mo
10 and 12
Cecchinato et al28
NA
Ericsson et al25 Koh et al27
Reference
Healing Period
Implant Shape
Implant Interimplant Threaded Surface Distance
Insertion Torque (Ncm)
Implant Loading
Jaw Location
Human Studies Cecchinato et al24
Tapered
Yes
MR
NA
NA
Yes*
Maxilla and Mandible
NA
Yes
MR
At least 3mm
NA
8 wk
NA
3.2 and 4.2
Tapered
Yes
MR
NA
30
2 wk
NA
NA
NA
Tapered
Yes
MR
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Yes*
NA
NA
NA
Tapered
Yes
MR
NA
NA
Not done
Maxilla
Cesaretti et al31
3 mo
NA
NA
Tapered
Yes
MR
NA
NA
Not done
Mandible
Hermann et al32
6 mo
9
3.5
Parallel-walled
Yes
MR
NA
NA
Not done
Mandible
Fiorellini et al33
3 mo
Submerged: 6.5 Nonsubmerged: 8
2.5
Parallel-walled
No
MR
NA
NA
Yes*
Mandible
CalvoGuirado et al19
NA
10
4
Tapered
Yes
MR
NA
NA
Not done
Mandible
CalvoGuirado et al16
2 mo
8
3.2 and 3.5
Tapered
Yes
MR
NA
NA
Not done
Mandible
Negri et al34
2 mo
10
3.75
Tapered and parallelwalled
Yes
MR
NA
NA
Not done
Mandible
Negri et al21
4 mo
10
3.8
Tapered
Yes
MR
NA
NA
Not done
Mandible
Carrdelli et al22 Nemli et al23
Nonsubmerged: Maxilla and Immediate Mandible loading Submerged: at least 12 mo Mandible
Animal Studies
MR, moderately rough; NA, not available. *Loading time was not reported.
reported. Five participants were smokers in the study by Nemli et al,23 and 21 were smokers in the study by Ericsson et al.25 However, these 2 studies did not report the daily frequency and duration of the smoking habit (Table 3). All studies16,19,21-25,27,28,31-34 earned 7 of the 9 possible stars in the NOS quality rating (Table 4).
Table 3. Study, smoking status, and residual bone thickness
Reference
Smokers
Daily Smoking Frequency (n)
Duration of Smoking Habit (y)
Human Studies Cecchinato et al24 Carrdelli et al22 Nemli et al23
NA
NA
NA
NA
None
NA
NA
At least 1.5 mm
5
NA
NA
At least 0.5 mm around the implant
DISCUSSION During the literature search, the author of the present systematic review identified a clinical study by Lambrecht et al,26 in which submerged and nonsubmerged solid-screw titanium implants were followed prospectively to analyze the long-term prognosis in partially and fully edentulous patients. The 10-year cumulative survival and success rate for submerged implants was 99.2% and for nonsubmerged implants was 96.4%.26 However, this study26 was excluded because the authors did not report the CBL or crestal bone levels around the submerged and nonsubmerged implants. Five22,24,25,27,28 of the six22-25,27,28 human studies showed no significant difference in CBL around submerged and THE JOURNAL OF PROSTHETIC DENTISTRY
Residual Bone Thickness
Cecchinato et al28
NA
NA
NA
NA
Ericsson et al25
21
NA
NA
NA
Koh et al27
NA
NA
NA
NA
Calvo-Guirado et al16
d
d
d
NA
Calvo-Guirado et al19
d
d
d
NA
Negri et al21
d
d
d
NA
Cesaretti et al31
d
d
d
NA
Hermann et al32
d
d
d
NA
Fiorellini et al33
d
d
d
NA
Negri et al34
d
d
d
NA
Animal studies
NA, not available.
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Table 4. Assessment of study quality with Newcastle-Ottawa scale Selection
Comparability
Study
S1
S2
S3
S4
C1
Cecchinato et al24
×
×
×
×
Carrdelli et al22
×
×
×
×
Nemli et al23
×
×
×
Cecchinato et al28
×
×
Ericsson et al25
×
Koh et al27
Exposure E2
×
×
×
7
×
×
×
7
×
×
×
×
7
×
×
×
×
×
7
×
×
×
×
×
×
7
×
×
×
×
×
×
×
7
Cesaretti et al31
×
×
×
×
×
×
×
7
Hermann et al32
×
×
×
×
×
×
×
7
Fiorellini et al33
×
×
×
×
×
×
×
7
Calvo-Guirado et al19
×
×
×
×
×
×
×
7
Calvo-Guirado et al16
×
×
×
×
×
×
×
7
Negri et al34
×
×
×
×
×
×
×
7
Negri et al21
×
×
×
×
×
×
×
7
Al Amri
E3
No. of stars (out of 9)
E1
nonsubmerged implants. In a split-mouth prospective study, Nemli et al23 reported significantly higher CBL around submerged implants (approximately 0.7 mm) than around nonsubmerged implants (approximately 0.6 mm); however, this study concluded that clinical results with nonsubmerged and submerged implants were comparable. During the first year, a mean CBL of 1 mm to 1.5 mm is considered acceptable, as is a 0.2 mm annual loss in subsequent years.35 Although in the study by Nemli et al23 CBL was higher around submerged than nonsubmerged implants, the mean CBL at 2 years of follow-up was within the acceptable range of CBL as reported by Mumcu et al.35 Factors such as poor bone quality, operator’s clinical skills, chronic periodontitis, and systemic diseases (such as, poorly controlled diabetes mellitus)36 that could have influenced CBL around implants were controlled in the studies that fulfilled the eligibility criteria. In all human studies, patients were given oral hygiene maintenance instructions and none of the studies reported a poorer periodontal status in any of the study groups. It is hypothesized that oral hygiene maintenance plays a more critical role in maintaining crestal bone levels than surgical intervention. Four19,32-34 of the 7 dog studies16,19,21,31-34 reported no significant difference in CBL around submerged and nonsubmerged dental implants. Two studies16,31 reported significantly higher CBL around nonsubmerged implants, whereas CBL was significantly higher around submerged than nonsubmerged implants in the study by Negri et al.21 This reflects an inconsistency among the 3 animal model-based studies, which reported a significant difference in CBL between submerged and nonsubmerged implants. In these studies, the follow-up period was relatively short (2 to 4 months) compared with that of human studies, in which patients were followed up to 60 months. Moreover, the study design varied in these studies.16,21,31 Perhaps, if the follow-up had been longer (at least 12 months) in the animal
C2
model-based studies, which showed a difference in CBL between submerged and nonsubmerged implants, no significant difference in CBL would have been found between submerged and nonsubmerged implants. If submerged/nonsubmerged techniques do affect bone levels, this effect could be associated with the postoperative healing period. The follow-up periods in human studies varied markedly, whereas in the studies based on animal models, the follow-up durations were relatively short (up to 6 months). However, all studies16,19,21-25,27,28,31-34 included in the present systematic review earned 7 stars out of the maximum score of 9 in the NOS quality rating. This indicates that the studies were well designed; however, the author believes it is critical to correlate CBL around submerged and nonsubmerged implants with the postoperative healing period. Further long-term prospective studies are needed to test this hypothesis. Surgical trauma and/or limited surgical experience may be essential causative factors that influence CBL around implants.37-40 Studies have also reported that early implant failure is common among surgeons who have placed fewer than 50 implants compared with those who have placed more.41,42 In this regard, the role of operator experience in placing dental implants should also be considered while assessing CBL, regardless of whether implants are placed in a submerged or nonsubmerged position.36 In the studies reviewed, all surgical procedures seem to have been performed by experienced clinicians. This factor may provide an additional explanation for the similarity in crestal bone levels around submerged and nonsubmerged dental implants. CONCLUSION Within the limits of the present review, it was concluded that no significant difference exists in CBL around submerged and nonsubmerged dental implants. THE JOURNAL OF PROSTHETIC DENTISTRY
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REFERENCES 1. Linkevicius T, Puisys A, Linkeviciene L, Peciuliene V, Schlee M. Crestal bone stability around implants with horizontally matching connection after soft tissue thickening: a prospective clinical trial. Clin Implant Dent Relat Res 2015;17:497-508. 2. Linkevicius T, Apse P, Grybauskas S, Puisys A. The influence of soft tissue thickness on crestal bone changes around implants: a 1-year prospective controlled clinical trial. Int J Oral Maxillofac Implants 2009;24:712-9. 3. Rodriguez-Ciurana X, Vela-Nebot X, Segala-Torres M, Rodado-Alonso C, Mendez-Blanco V, Mata-Bugueroles M. Biomechanical repercussions of bone resorption related to biologic width: a finite element analysis of three implant-abutment configurations. Int J Periodontics Restorative Dent 2009;29:479-87. 4. Romanos GE, Aydin E, Gaertner K, Nentwig GH. Long-term results after subcrestal or crestal placement of delayed loaded implants. Clin Implant Dent Relat Res 2015;17:133-41. 5. Rodriguez-Ciurana X, Vela-Nebot X, Segala-Torres M, Calvo-Guirado JL, Cambra J, Méndez-Blanco V, et al. The effect of interimplant distance on the height of the interimplant bone crest when using platform-switched implants. Int J Periodontics Restorative Dent 2009;29:141-51. 6. Canullo L, Iannello G, Penarocha M, Garcia B. Impact of implant diameter on bone level changes around platform switched implants: preliminary results of 18 months follow-up a prospective randomized match-paired controlled trial. Clin Oral Implants Res 2012;23:1142-6. 7. Javed F, Almas K, Crespi R, Romanos GE. Implant surface morphology and primary stability: is there a connection? Implant Dent 2011;20:40-6. 8. Naert I, Duyck J, Vandamme K. Occlusal overload and bone/implant loss. Clin Oral Implants Res 2012;23 Suppl 6:95-107. 9. Ibbott CG, Kovach RJ, Carlson-Mann LD. Acute periodontal abscess associated with an immediate implant site in the maintenance phase: a case report. Int J Oral Maxillofac Implants 1993;8:699-702. 10. Charalampakis G, Abrahamsson I, Carcuac O, Dahlen G, Berglundh T. Microbiota in experimental periodontitis and peri-implantitis in dogs. Clin Oral Implants Res 2014;25:1094-8. 11. Romanos GE, Javed F, Delgado-Ruiz RA, Calvo-Guirado JL. Peri-implant diseases: a review of treatment interventions. Dent Clin North Am 2015;59: 157-78. 12. Albrektsson T, Zarb G, Worthington P, Eriksson AR. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11-25. 13. Romanos GE, Weitz D. Therapy of peri-implant diseases. Where is the evidence? J Evid Based Dent Pract 2012;12:204-8. 14. Romanos GE, Javed F. Platform switching minimises crestal bone loss around dental implants: truth or myth? J Oral Rehabil 2014;41:700-8. 15. Vohra F, Al-Khuraif AA, Almas K, Javed F. Comparison of crestal bone loss around dental implants placed in healed sites using flapped and flapless techniques: a systematic review. J Periodontol 2015;86:185-91. 16. Calvo-Guirado JL, Perez-Albacete C, Aguilar-Salvatierra A, de Val MatéSánchez JE, Delgado-Ruiz RA, Abboud M, Velasco E, et al. Narrow- versus mini-implants at crestal and subcrestal bone levels. Experimental study in beagle dogs at three months. Clin Oral Investig 2015;19:1363-9. 17. Buser D, Belser UC, Lang NP. The original one-stage dental implant system and its clinical application. Periodontol 2000;1998(17):106-18. 18. Novaes AB Jr, Barros RR, Muglia VA, Borges GJ. Influence of interimplant distances and placement depth on papilla formation and crestal resorption: a clinical and radiographic study in dogs. J Oral Implantol 2009;35:18-27. 19. Calvo-Guirado JL, Lopez-Lopez PJ, Mate Sanchez JE, Gargallo Albiol J, Velasco Ortega E, Delgado Ruiz R. Crestal bone loss related to immediate implants in crestal and subcrestal position: a pilot study in dogs. Clin Oral Implants Res 2014;25:1286-94. 20. Negri B, Calvo-Guirado JL, Ramirez-Fernandez MP, Mate Sanchez-de Val J, Guardia J, Munoz-Guzon F. Peri-implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part II: a pilot study in dogs. Clin Oral Implants Res 2012;23:236-44. 21. Negri B, Lopez Mari M, Mate Sanchez de Val JE, Iezzi G, Bravo Gonzalez LA, Calvo Guirado JL. Biological width formation to immediate implants placed at different level in relation to the crestal bone: an experimental study in dogs. Clin Oral Implants Res 2015;26:788-98. 22. Cardelli P, Cecchetti F, Montani M, Bramanti E, Arcuri C. Clinical assessment of submerged vs non-submerged implants placed in pristine bone. Oral Implantol (Rome) 2013;6:89-93. 23. Nemli SK, Gungor MB, Aydin C, Yilmaz H, Turkcan I, Demirkoprulu H. Clinical evaluation of submerged and non-submerged implants for posterior single-tooth replacements: a randomized split-mouth clinical trial. Int J Oral Maxillofac Surg 2014;43:1484-92.
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24. Cecchinato D, Olsson C, Lindhe J. Submerged or non-submerged healing of endosseous implants to be used in the rehabilitation of partially dentate patients. J Clin Periodontol 2004;31:299-308. 25. Ericsson I, Randow K, Nilner K, Petersson A. Some clinical and radiographical features of submerged and non-submerged titanium implants. A 5-year follow-up study. Clin Oral Implants Res 1997;8:422-6. 26. Lambrecht JT, Filippi A, Kunzel AR, Schiel HJ. Long-term evaluation of submerged and nonsubmerged ITI solid-screw titanium implants: a 10-year life table analysis of 468 implants. Int J Oral Maxillofac Implants 2003;18: 826-34. 27. Koh RU, Oh TJ, Rudek I, Neiva GF, Misch CE, Rothman ED, et al. Hard and soft tissue changes after crestal and subcrestal immediate implant placement. J Periodontol 2011;82:1112-20. 28. Cecchinato D, Bengazi F, Blasi G, Botticelli D, Cardarelli I, Gualini F. Bone level alterations at implants placed in the posterior segments of the dentition: outcome of submerged/non-submerged healing. A 5-year multicenter, randomized, controlled clinical trial. Clin Oral Implants Res 2008;19:429-31. 29. BoudinF Nie JY, Bartlett JC, Grad R, Pluye P, Dawes M. Combining classifiers for robust PICO element detection. BMC Med Inform Decis Mak 2010;10:29. 30. Cook DA, Reed DA. Appraising the quality of medical education research methods: the Medical Education Research Study Quality Instrument and the Newcastle-Ottawa scale-education. Acad Med 2015;90:1067-76. 31. Cesaretti G, Lang NP, Salata LA, Schweikert MT, Gutierrez Hernandez ME, Botticelli D. Sub-crestal positioning of implants results in higher bony crest resorption: an experimental study in dogs. Clin Oral Implants Res 2015;26: 1355-60. 32. Hermann JS, Buser D, Schenk RK, Cochran DL. Crestal bone changes around titanium implants. A histometric evaluation of unloaded nonsubmerged and submerged implants in the canine mandible. J Periodontol 2000;71:1412-24. 33. Fiorellini JP, Buser D, Paquette DW, Williams RC, Haghighi D, Weber HP. A radiographic evaluation of bone healing around submerged and nonsubmerged dental implants in beagle dogs. J Periodontol 1999;70:248-54. 34. Negri B, Calvo-Guirado JL, Pardo-Zamora G, Ramirez-Fernandez MP, Delgado-Ruiz RA, Munoz-Guzon F. Peri-implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part I: a pilot study in dogs. Clin Oral Implants Res 2012;23: 228-35. 35. Mumcu E, Bilhan H, Geckili O. The influence of healing type on marginal bone levels of implants supporting mandibular overdentures: a randomized clinical study. Indian J Dent Res 2012;23:514-8. 36. Porter JA, von Fraunhofer JA. Success or failure of dental implants? A literature review with treatment considerations. Gen Dent 2005;53:423-32. quiz 433, 446. 37. el Askary AS, Meffert RM, Griffin T. Why do dental implants fail? Part II. Implant Dent 1999;8:265-77. 38. Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributing to failures of osseointegrated oral implants. (II). Etiopathogenesis. Eur J Oral Sci 1998;106:721-64. 39. Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology. Eur J Oral Sci 1998;106:527-51. 40. Cosyn J, Vandenbulcke E, Browaeys H, Van Maele G, De Bruyn H. Factors associated with failure of surface-modified implants up to four years of function. Clin Implant Dent Relat Res 2012;14:347-58. 41. Morris HF, Manz MC, Tarolli JH. Success of multiple endosseous dental implant designs to second-stage surgery across study sites. J Oral Maxillofac Surg 1997;55:76-82. 42. Lambert PM, Morris HF, Ochi S. Positive effect of surgical experience with implants on second-stage implant survival. J Oral Maxillofac Surg 1997;55: 12-8. Corresponding author: Dr Mohammad D. Al Amri Department of Prosthetic Dental Sciences College of Dentistry King Saud University PO Box 60169 Riyadh 11545 SAUDI ARABIA Email: [email protected] Copyright © 2016 by the Editorial Council for The Journal of Prosthetic Dentistry.
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SUPPLEMENTAL MATERIAL a. Lombardo G, Corrocher G, Pighi J, Faccioni F, Rovera A, Marincola M, et al. The impact of subcrestal placement on short locking-taper implants placed in posterior maxilla and mandible: a retrospective evaluation on hard and soft tissues stability after 2 years of loading. Minerva Stomatol 2014;63:391-402. (Focused question was not answered). b. Lambrecht JT, Filippi A, Kunzel AR, Schiel HJ. Long-term evaluation of submerged and nonsubmerged ITI solid-screw titanium implants: a 10-year life table analysis of 468 implants. Int J Oral Maxillofac Implants 2003;18: 826-34. (Crestal bone loss was not reported). c. Palaska I, Tsaousoglou P, Vouros I, Konstantinidis A, Menexes G. Influence of placement depth and abutment connection pattern on bone remodeling around 1-stage implants: a prospective randomized controlled clinical trial. Clin Oral Implants Res 2016;27:e47-56. (Platform switched implants were used). d. Schwarz F, Mihatovic I, Golubovich V, Schär A, Sager M, Becker J. Impact of abutment microstructure and insertion depth on crestal bone changes at nonsubmerged titanium implants with platform switch. Clin Oral Implants Res 2015;26:287-92. (Platform switched implants were used). e. Kutan-Misirlioglu E, Bolukbasi N, Yildirim-Ondur E, Ozdemir T. clinical and radiographic evaluation of marginal bone changes around platformswitching implants placed in crestal or subcrestal positions: a randomized controlled clinical trial. Clin Implant Dent Relat Res 2015;17:e364-75. (Platform switched implants were used). f. Lee J, Fiorini T, Gamborena I, Wenzel BA, Schüpbach P, Wikesjö UM, et al. Effect of platform shift/switch on crestal bone levels and mucosal profile following flapless surgery and crestal/subcrestal implant placement. Clin Implant Dent Relat Res 2016;18:73-81. g. Laster Z, Weissberg I, Kablan F. Biomechanics and peri-implantitis: The effect of a subcrestal wing-thread to decrease alveolarcrestal bone strain. theory, finite element analysis, and clinical application. Int J Oral Maxillofac Implants 2014;29:e265-71. (Focused question was not answered). h. Wenzel BA, Gamborena I, Lee J, Fiorini T, Schüpbach P, Wikesjö UM, et al. Effect of platform shift on crestal bone levels and mucosal profile following flap surgery and subcrestal implant placement in presence/absence of gap defects. Clin Implant Dent Relat Res 2016;18:217-25. i. Schwarz F, Alcoforado G, Nelson K, Schaer A, Taylor T, Beuer F, et al. Impact of implant-abutment connection, positioning of the machined collar/microgap, and platform switching on crestal bone level changes. Camlog
Al Amri
j. k.
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m.
n.
o.
p. q.
r.
s.
Foundation Consensus Report. Clin Oral Implants Res 2014;25:1301-3. (Focused question was not answered). Romanos GE, Aydin E, Gaertner K, Nentwig GH. Long-Term Results after Subcrestal or Crestal Placement of Delayed Loaded Implants. Clin Implant Dent Relat Res 2015;17:133-41. (Platform switched implants were used). Suaid FA, Novaes AB Jr, Queiroz AC, Muglia VA, Almeida AL, Grisi MF. Buccal bone plate remodeling after immediate implants with or without synthetic bone grafting and flapless surgery: a histomorphometric and fluorescence study in dogs. Clin Oral Implants Res 2014;25:e10-21. (Focused question was not answered). Alonso-González R, Aloy-Prósper A, Peñarrocha-Oltra D, PeñarrochaDiago MA, Peñarrocha-Diago M. Marginal bone loss in relation to platform switching implant insertion depth: An update. J Clin Exp Dent 2012;4:e173-9. (Review article). Huang B, Meng H, Piao M, Xu L, Zhang L, Zhu W. Influence of placement depth on bone remodeling around tapered internal connection implant: a clinical and radiographic study in dogs. J Periodontol 2012;83:1164-71. (Focused question was not answered). Veis A, Parissis N, Tsirlis A, Papadeli C, Marinis G, Zogakis A. Evaluation of peri-implant marginal bone loss using modified abutment connections at variouscrestal level placements. Int J Periodontics Restorative Dent 2010;30: 609-17. (Platform switched implants were used). Donovan R, Fetner A, Koutouzis T, Lundgren T. Crestal bone changes around implants with reduced abutment diameter placed non-submerged and at subcrestal positions: a 1-year radiographic evaluation. J Periodontol 2010;81:428-34. (Bone grafting was performed). Vidal R, Greenwell H, Hill M, Papageorgakopoulos G, Scheetz JP. Success rate of immediate implants placed and restored by novice operators. Implant Dent 2010;19:81-90. (Platform switched implants were used). Barros RR, Novaes AB Jr, Muglia VA, Iezzi G, Piattelli A. Influence of interimplant distances and placement depth on peri-implant bone remodeling of adjacent and immediately loaded Morse cone connection implants: a histomorphometric study in dogs. Clin Oral Implants Res 2010;21:371-8. (Focused question was not answered). Baggi L, Cappelloni I, Di Girolamo M, Maceri F, Vairo G. The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis. J Prosthet Dent 2008;100:422-31. (Focused question was not answered). Broggini N, McManus LM, Hermann JS, Medina R, Schenk RK, Buser D, et al. Peri-implant inflammation defined by the implant-abutment interface. J Dent Res 2006;85:473-8. (Focused question was not answered).
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Crestal bone loss around submerged and nonsubmerged dental implants: A systematic review Mohammad D. Al Amri, BDS, MS, FRCDC A variety of factors have been ABSTRACT associated with crestal bone Statement of problem. To my knowledge, there is no systematic review of crestal bone loss (CBL) loss (CBL) around dental imaround submerged and nonsubmerged dental implants. plants, including periodontal Purpose. The purpose of this review was to systematically assess CBL around submerged and biotype,1,2 bone density and nonsubmerged dental implants. the formation of biological Material and methods. The addressed focused question was, “Does crestal and subcrestal width,3 implant placement placement of dental implants influence crestal bone levels?” Databases were searched from 1986 4 5 depth, interimplant distance, through October 2015 using different combinations of the following keywords: crestal, sub-crestal, implant microdesign and bone loss, dental implant, submerged, and nonsubmerged. Reference lists of potentially relevant macrodesign,6,7 occlusal overoriginal and review articles were hand-searched to identify any further studies. Letters to the loading,8 and surgical trauma.9 editor, case reports, commentaries, studies on platform-switched implants, and studies published The early loss of crestal bone in languages other than English were excluded. facilitates the stagnation and Results. In total, 13 studies (6 human and 7 animal), which were performed at universities, were proliferation of anaerobic bacincluded. In the human studies, the number of participants ranged from 8 to 84 individuals. The teria on exposed implant follow-up period ranged from 1 to 5 years. CBL at the test sites ranged from 0.17 mm to 0.9 mm and surfaces, which if left unconat control sites from 0.02 mm to 1.4 mm. Five human studies reported no significant difference in CBL around implants placed at the test and control sites. All animal studies were performed in dogs trolled or untreated may result with a mean age ranging from 1 to approximately 2 years. The follow-up period ranged from 2 to 6 in the further loss of periimmonths. Four animal studies reported no significant difference in CBL around submerged and 10,11 plant bone. However, acnonsubmerged implants. 12 cording to Albrektsson et al, Conclusion. No significant difference in CBL was found around submerged and nonsubmerged an annual 0.1 to 0.2 mm of dental implants. (J Prosthet Dent 2016;115:564-570) CBL after implant loading is a normal phenomenon that occurs as a result of crestal bone remodeling. In this regard, reference to the alveolar crest) influences marginal bone controlling CBL is essential for the long-term success and resorption, and placing them in a submerged position survival of implants. aids in obtaining an ideal emergence profile in esthetic No one definitive therapeutic strategy is most areas.17 One explanation is that placement of the 13 effective in minimizing CBL around implants ; howimplant-abutment interface in a submerged position ever, protocols that have been proposed to minimize the contributes to the maintenance of mucosa texture and loss of crestal bone include the use of platform switched tonality and also favors the reestablishment of favorable implants, using a flapless surgical technique, and marginal tissue architecture as compared with implants placing dental implants approximately 2 mm below the placed at the level of the alveolar crest (nonsubmerged/ alveolar crest (submerged/subcrestal placement).14-16 crestal implants).18 In addition, studies have shown that Placing implants in the vertical dimension (with implants placed in a nonsubmerged position undergo
Associate Professor and Consultant, Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
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significantly more crestal bone loss than implants placed in a submerged position.19-21 Although placing implants in a submerged position would compensate for crestal bone remodeling and improve bone-to-implant contact in the implant neck region, controversial results have also been reported.22-28 In a prospective split-mouth randomized controlled clinical trial, 18 implants were submerged in bone and 18 were placed in a nonsubmerged position in 20 participants.23 After 24 months of follow-up, the radiographic assessment of periimplant bone showed a statistically significant difference in CBL around the submerged and nonsubmerged implants.23 Similar results were reported in a retrospective study in which 342 submerged and 146 nonsubmerged implants were placed in 191 patients and radiographically assessed after 10 years of followup.26 However, according to indexed publications, a systematic review of crestal bone loss (CBL) around submerged and nonsubmerged dental implants has not yet been performed. With this background, the purpose of the present review was to systematically assess CBL around submerged and nonsubmerged dental implants. MATERIAL AND METHODS Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a specific question was constructed according to the Participants, Interventions, Control, Outcomes (PICO) principle (Fig. 1).29 The addressed focused question was “Does crestal and subcrestal placement of dental implants influence crestal bone levels?” P – Participants: Participants must have undergone dental implant treatment. I – Types of interventions: The intervention of interest was the placement of implants using the submerged technique (ST). C – Control intervention: Implants were placed using non-ST. O – Outcome measures: CBL around implants placed using ST and non-ST. The inclusion criteria were as follows: original studies; human (clinical) studies; studies based on animal models (experimental); inclusion of a control group; and intervention: CBL around submerged and nonsubmerged dental implants. Letters to the editor, case reports, case Al Amri
Screening
0 records identified through manual search
13 records selected after duplicates removed
Eligibility
The currently available evidence shows no significant difference in crestal bone loss around submerged and nonsubmerged dental implants.
32 records identified through electronic searches
13 full-text articles assessed for eligibility
Included
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Identification
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13 studies included in the systematic review
19 excluded after screening titles and abstracts Studies which did not answer the focused question: 10 Studies in which platform switched implants were used: 7 Review articles: 2
Figure 1. Article selection flowchart.
series, commentaries, historical review, and articles published in languages other than English were excluded. In an attempt to identify studies pertinent to the PICO question, the following databases were electronically searched for available data: PubMed/MEDLINE (OVID), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Web of Knowledge, Cumulative Index to Nursing and Allied Health Literature, and Google-Scholar. These databases were searched from 1986 through October 2015 using different combinations of the following keywords: crestal, sub-crestal, bone loss, dental implant, submerged, and nonsubmerged. Titles and abstracts of studies identified using the described protocol were screened. Full texts of studies judged by title and abstract to be relevant were read and evaluated in accordance with the following eligibility criteria: clinical and experimental studies, assessment of periimplant clinical parameters, and CBL around submerged and nonsubmerged dental implants. Reference lists of potentially relevant original and review articles were hand searched to identify any further studies. Articles available online in electronic form ahead of print were considered eligible for inclusion. Letters to the editor, case reports, commentaries, and studies published in languages other than English were not sought. Moreover, studies on platform-switched implants were also excluded because platform-switching has been reported to influence periimplant bone levels.14 The pattern of the present systematic review was customized mainly to summarize the relevant data. Excluded studies and reasons for exclusion are listed in the Supplemental Material. The Newcastle-Ottawa scale (NOS) was used to grade the methodological quality of each study assessed in the present systematic review.30 This scale uses a systematic approach based on 3 specific criteria: selection (S), comparability (C), and exposure (E). These are subdivided into 9 criteria: S1, adequate case definition; S2, representativeness of the cases; S3, selection of THE JOURNAL OF PROSTHETIC DENTISTRY
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Table 1. Characteristics of studies included
Reference
Study Design
Randomized Controlled Trial
No. of Implants (n)
No. of Participants (n)
Mean Age (y)
Study Groups (n = no. of implants)
Follow-up
Bone Loss (Test Sites)
Bone Loss (Control Sites)
Significant Difference
Human Studies Cecchinato et al24
Prospective
Yes
324
84
51.6
Group-1: submerged implants (n=NA) Group-2: nonsubmerged implants (n=NA)
2y
0.17 mm
0.02 mm
No
Carrdelli et al22
Prospective Split-mouth
No
16
8
>21*
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
3y
0.25 mm
0.25 mm
No
Nemli et al23
Prospective Split-mouth
Yes
36
20
38.4
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2y
0.68 mm
0.57 mm
Yes
Cecchinato et al28
Prospective
Yes
324
84
NA
Test site: submerged implants (n=153) Control site: nonsubmerged implants (n=171)
5y
0.17 mm
0.02 mm
No
Ericsson et al25
Prospective Split-mouth
No
61
11 patients
NA
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
5y
1.5 mm
1.4 mm
No
Koh et al27
Prospective
Yes
20
20 patients
55.5
Group-1: submerged implants (n=10) Group-2: nonsubmerged implants (n=10)
1y
0.9 mm
1.4 mm
No
Calvo-Guirado et al16
Prospective Split-mouth
Yes
48
6 dogs
1
Test site: submerged implants (n=24) Control site: Nonsubmerged implants (n=24)
4 mo
0.91 mm
1.89 mm
Yes
Calvo-Guirado et al19
Prospective Split-mouth
Yes
48
6 dogs
1
Test site: submerged implants (n=24) Control site: nonsubmerged implants (n=24)
3 mo
0.93 mm
0.95 mm
No
Negri et al21
Prospective Split-mouth
Yes
36
6 dogs
1
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2 mo
2.05
1.75
Yes
Cesaretti et al31
Prospective
No
25
6 dogs
1
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
2 mo
1.4 mm
2.2 mm
Yes
Hermann et al32
Prospective
Yes
59
5 dogs
w2
Test site: submerged implants (n=NA) Control site: nonsubmerged implants (n=NA)
6 mo
1.68 mm
1.57 mm
No
Animal Studies
(continued on next page)
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Table 1. (continued) Characteristics of studies included Randomized Controlled Trial
No. of Implants (n)
No. of Participants (n)
Mean Age (y)
Study Groups (n = no. of implants)
Follow-up
Bone Loss (Test Sites)
Bone Loss (Control Sites)
Significant Difference
Reference
Study Design
Fiorellini et al33
Prospective Split-mouth
Yes
38
6 dogs
1.5
Test site: submerged implants (n=19) Control site: nonsubmerged implants (n=19)
4.5 mo
0.92 mm
0.99 mm
No
Negri et al34
Prospective Split-mouth
Yes
36
6 dogs
1
Test site: submerged implants (n=18) Control site: nonsubmerged implants (n=18)
2 mo
0.67 mm
0.62 mm
No
*The exact age was not reported.
control; S4, definition of control; C1, comparability of cases; C2, controls on the basis of the analysis; E1, ascertainment of exposure; E2, same method of ascertainment for cases and controls; E3, nonresponse rate. Each criterion was given a response of “Yes,” “No,” or ‘‘cannot tell.’’ Maximum possible score for each study was 9. RESULTS In total, 13 studies16,19,21-25,27,28,31-34 (6 human22-25,27,28 and 7 animal16,19,21,31-34), which were performed at universities, were included. All human studies included22-25,27,28 were prospective, and 4 studies23,24,27,28 were randomized controlled trials (RCTs). The number of participants ranged from 8 to 84 individuals. Four studies22-24,27 reported the mean age of the participants, which ranged from older than 21 to 55.5 years. Three studies23,27,28 reported the numbers of implants placed in crestal (control sites) and subcrestal (test sites) positions, which ranged from 18 to 171 implants. The follow-up period ranged from 1 to 5 years.22-25,27,28 CBL at the test sites ranged from 0.17 to 0.9 mm and at control sites from 0.02 to 1.4 mm. Five22,24,27,28 of the 6 studies22-25,27,28 reported no significant difference in CBL around implants placed at the test and control sites. In the study by Nemli et al,23 CBL was significantly higher at the test sites than at the control sites (Table 1). However, the remaining studies included16,19,21,31-34 were prospective and were performed in dogs (range: 5 to 6 dogs), with a mean age from 1 to about 2 years. Five studies16,19,21,32,33 had a split-mouth design. The number of implants placed in the participants ranged from 25 to 59 implants.16,19,21,31-34 Six studies16,19,21,32-34 were RCTs. Five studies16,19,21,33,34 reported the numbers of implants placed in the test and control sites, which ranged from 18 to 24 implants. The follow-up period ranged from 2 to 6 months. CBL at the test sites ranged from 0.92 to 2.05 mm and at the control sites from 0.62 to 2.2 mm. Three studies16,21,31 reported a statistically significant difference in CBL around implants placed in the test and control Al Amri
sites. In the studies by Cesaretti et al31 and CalvoGuirado et al,16 CBL was significantly higher in the control sites than test sites, whereas, in the study by Negri et al,21 CBL was higher around the test sites than the control sites (Table 1). Three studies22-24 reported the healing period after implant placement, which ranged from 1.5 to 9 months. Two studies23,24 reported the length of the implants used, which ranged from 10 to 12 mm. Implant diameters, which ranged from 3.2 to 5.5 mm, were reported in 3 studies.22-24 In 4 studies,23,24,27,28 tapered implants were used, while in 2 studies22,25 implant shape was not reported. In 1 study,25 implant dimensions and surface characteristics were not reported. In the study by Ericsson et al,25 submerged and nonsubmerged implants were placed in the mandible, and in the study by Koh et al,27 submerged and nonsubmerged implants were placed in the maxilla. In 2 studies,22,23 jaw location was not reported. In 6 studies,22-24,26-28 moderately rough-surfaced tapered threaded implants were used. In 1 study,25 implant surface characteristics were not reported. In the study by Cardelli et al,22 the interimplant distance was reported, and Nemli et al23 reported the implant insertion torque. In 5 studies,22-25,28 implants were loaded, and the loading time ranged from 2 weeks to 12 months after placement (Table 2). In all animal studies,16,19,21,31-34 the implants were placed in the mandible and had moderately rough surfaces. Six studies16,21,31-34 reported the healing period after implant placement, which ranged from 2 to 6 months. Six studies16,19,21,32-34 reported the length (6.5 to 10 mm) and diameter (2.5 to 4 mm) of the implants used. In four studies,16,19,21,31 tapered implants were used, and in 2 studies32,33 parallel-walled implants were placed using submerged and nonsubmerged techniques. In 1 study,34 both tapered and parallelwalled implants were placed using submerged and nonsubmerged techniques. None of the studies reported interimplant distances and implant insertion torques. In 1 study,33 although implants were loaded, the time of loading (immediate or delayed) was not THE JOURNAL OF PROSTHETIC DENTISTRY
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Table 2. Implant-related characteristics of studies included Implant Length (mm)
Implant Diameter (mm)
3 to 6 mo
w12
3.5 and 4
1.5 to 2 mo
NA
3.4, 3.8, 4.5 and 5.5
3 to 4 mo
10 and 12
Cecchinato et al28
NA
Ericsson et al25 Koh et al27
Reference
Healing Period
Implant Shape
Implant Interimplant Threaded Surface Distance
Insertion Torque (Ncm)
Implant Loading
Jaw Location
Human Studies Cecchinato et al24
Tapered
Yes
MR
NA
NA
Yes*
Maxilla and Mandible
NA
Yes
MR
At least 3mm
NA
8 wk
NA
3.2 and 4.2
Tapered
Yes
MR
NA
30
2 wk
NA
NA
NA
Tapered
Yes
MR
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Yes*
NA
NA
NA
Tapered
Yes
MR
NA
NA
Not done
Maxilla
Cesaretti et al31
3 mo
NA
NA
Tapered
Yes
MR
NA
NA
Not done
Mandible
Hermann et al32
6 mo
9
3.5
Parallel-walled
Yes
MR
NA
NA
Not done
Mandible
Fiorellini et al33
3 mo
Submerged: 6.5 Nonsubmerged: 8
2.5
Parallel-walled
No
MR
NA
NA
Yes*
Mandible
CalvoGuirado et al19
NA
10
4
Tapered
Yes
MR
NA
NA
Not done
Mandible
CalvoGuirado et al16
2 mo
8
3.2 and 3.5
Tapered
Yes
MR
NA
NA
Not done
Mandible
Negri et al34
2 mo
10
3.75
Tapered and parallelwalled
Yes
MR
NA
NA
Not done
Mandible
Negri et al21
4 mo
10
3.8
Tapered
Yes
MR
NA
NA
Not done
Mandible
Carrdelli et al22 Nemli et al23
Nonsubmerged: Maxilla and Immediate Mandible loading Submerged: at least 12 mo Mandible
Animal Studies
MR, moderately rough; NA, not available. *Loading time was not reported.
reported. Five participants were smokers in the study by Nemli et al,23 and 21 were smokers in the study by Ericsson et al.25 However, these 2 studies did not report the daily frequency and duration of the smoking habit (Table 3). All studies16,19,21-25,27,28,31-34 earned 7 of the 9 possible stars in the NOS quality rating (Table 4).
Table 3. Study, smoking status, and residual bone thickness
Reference
Smokers
Daily Smoking Frequency (n)
Duration of Smoking Habit (y)
Human Studies Cecchinato et al24 Carrdelli et al22 Nemli et al23
NA
NA
NA
NA
None
NA
NA
At least 1.5 mm
5
NA
NA
At least 0.5 mm around the implant
DISCUSSION During the literature search, the author of the present systematic review identified a clinical study by Lambrecht et al,26 in which submerged and nonsubmerged solid-screw titanium implants were followed prospectively to analyze the long-term prognosis in partially and fully edentulous patients. The 10-year cumulative survival and success rate for submerged implants was 99.2% and for nonsubmerged implants was 96.4%.26 However, this study26 was excluded because the authors did not report the CBL or crestal bone levels around the submerged and nonsubmerged implants. Five22,24,25,27,28 of the six22-25,27,28 human studies showed no significant difference in CBL around submerged and THE JOURNAL OF PROSTHETIC DENTISTRY
Residual Bone Thickness
Cecchinato et al28
NA
NA
NA
NA
Ericsson et al25
21
NA
NA
NA
Koh et al27
NA
NA
NA
NA
Calvo-Guirado et al16
d
d
d
NA
Calvo-Guirado et al19
d
d
d
NA
Negri et al21
d
d
d
NA
Cesaretti et al31
d
d
d
NA
Hermann et al32
d
d
d
NA
Fiorellini et al33
d
d
d
NA
Negri et al34
d
d
d
NA
Animal studies
NA, not available.
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Table 4. Assessment of study quality with Newcastle-Ottawa scale Selection
Comparability
Study
S1
S2
S3
S4
C1
Cecchinato et al24
×
×
×
×
Carrdelli et al22
×
×
×
×
Nemli et al23
×
×
×
Cecchinato et al28
×
×
Ericsson et al25
×
Koh et al27
Exposure E2
×
×
×
7
×
×
×
7
×
×
×
×
7
×
×
×
×
×
7
×
×
×
×
×
×
7
×
×
×
×
×
×
×
7
Cesaretti et al31
×
×
×
×
×
×
×
7
Hermann et al32
×
×
×
×
×
×
×
7
Fiorellini et al33
×
×
×
×
×
×
×
7
Calvo-Guirado et al19
×
×
×
×
×
×
×
7
Calvo-Guirado et al16
×
×
×
×
×
×
×
7
Negri et al34
×
×
×
×
×
×
×
7
Negri et al21
×
×
×
×
×
×
×
7
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E3
No. of stars (out of 9)
E1
nonsubmerged implants. In a split-mouth prospective study, Nemli et al23 reported significantly higher CBL around submerged implants (approximately 0.7 mm) than around nonsubmerged implants (approximately 0.6 mm); however, this study concluded that clinical results with nonsubmerged and submerged implants were comparable. During the first year, a mean CBL of 1 mm to 1.5 mm is considered acceptable, as is a 0.2 mm annual loss in subsequent years.35 Although in the study by Nemli et al23 CBL was higher around submerged than nonsubmerged implants, the mean CBL at 2 years of follow-up was within the acceptable range of CBL as reported by Mumcu et al.35 Factors such as poor bone quality, operator’s clinical skills, chronic periodontitis, and systemic diseases (such as, poorly controlled diabetes mellitus)36 that could have influenced CBL around implants were controlled in the studies that fulfilled the eligibility criteria. In all human studies, patients were given oral hygiene maintenance instructions and none of the studies reported a poorer periodontal status in any of the study groups. It is hypothesized that oral hygiene maintenance plays a more critical role in maintaining crestal bone levels than surgical intervention. Four19,32-34 of the 7 dog studies16,19,21,31-34 reported no significant difference in CBL around submerged and nonsubmerged dental implants. Two studies16,31 reported significantly higher CBL around nonsubmerged implants, whereas CBL was significantly higher around submerged than nonsubmerged implants in the study by Negri et al.21 This reflects an inconsistency among the 3 animal model-based studies, which reported a significant difference in CBL between submerged and nonsubmerged implants. In these studies, the follow-up period was relatively short (2 to 4 months) compared with that of human studies, in which patients were followed up to 60 months. Moreover, the study design varied in these studies.16,21,31 Perhaps, if the follow-up had been longer (at least 12 months) in the animal
C2
model-based studies, which showed a difference in CBL between submerged and nonsubmerged implants, no significant difference in CBL would have been found between submerged and nonsubmerged implants. If submerged/nonsubmerged techniques do affect bone levels, this effect could be associated with the postoperative healing period. The follow-up periods in human studies varied markedly, whereas in the studies based on animal models, the follow-up durations were relatively short (up to 6 months). However, all studies16,19,21-25,27,28,31-34 included in the present systematic review earned 7 stars out of the maximum score of 9 in the NOS quality rating. This indicates that the studies were well designed; however, the author believes it is critical to correlate CBL around submerged and nonsubmerged implants with the postoperative healing period. Further long-term prospective studies are needed to test this hypothesis. Surgical trauma and/or limited surgical experience may be essential causative factors that influence CBL around implants.37-40 Studies have also reported that early implant failure is common among surgeons who have placed fewer than 50 implants compared with those who have placed more.41,42 In this regard, the role of operator experience in placing dental implants should also be considered while assessing CBL, regardless of whether implants are placed in a submerged or nonsubmerged position.36 In the studies reviewed, all surgical procedures seem to have been performed by experienced clinicians. This factor may provide an additional explanation for the similarity in crestal bone levels around submerged and nonsubmerged dental implants. CONCLUSION Within the limits of the present review, it was concluded that no significant difference exists in CBL around submerged and nonsubmerged dental implants. THE JOURNAL OF PROSTHETIC DENTISTRY
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24. Cecchinato D, Olsson C, Lindhe J. Submerged or non-submerged healing of endosseous implants to be used in the rehabilitation of partially dentate patients. J Clin Periodontol 2004;31:299-308. 25. Ericsson I, Randow K, Nilner K, Petersson A. Some clinical and radiographical features of submerged and non-submerged titanium implants. A 5-year follow-up study. Clin Oral Implants Res 1997;8:422-6. 26. Lambrecht JT, Filippi A, Kunzel AR, Schiel HJ. Long-term evaluation of submerged and nonsubmerged ITI solid-screw titanium implants: a 10-year life table analysis of 468 implants. Int J Oral Maxillofac Implants 2003;18: 826-34. 27. Koh RU, Oh TJ, Rudek I, Neiva GF, Misch CE, Rothman ED, et al. Hard and soft tissue changes after crestal and subcrestal immediate implant placement. J Periodontol 2011;82:1112-20. 28. Cecchinato D, Bengazi F, Blasi G, Botticelli D, Cardarelli I, Gualini F. Bone level alterations at implants placed in the posterior segments of the dentition: outcome of submerged/non-submerged healing. A 5-year multicenter, randomized, controlled clinical trial. Clin Oral Implants Res 2008;19:429-31. 29. BoudinF Nie JY, Bartlett JC, Grad R, Pluye P, Dawes M. Combining classifiers for robust PICO element detection. BMC Med Inform Decis Mak 2010;10:29. 30. Cook DA, Reed DA. Appraising the quality of medical education research methods: the Medical Education Research Study Quality Instrument and the Newcastle-Ottawa scale-education. Acad Med 2015;90:1067-76. 31. Cesaretti G, Lang NP, Salata LA, Schweikert MT, Gutierrez Hernandez ME, Botticelli D. Sub-crestal positioning of implants results in higher bony crest resorption: an experimental study in dogs. Clin Oral Implants Res 2015;26: 1355-60. 32. Hermann JS, Buser D, Schenk RK, Cochran DL. Crestal bone changes around titanium implants. A histometric evaluation of unloaded nonsubmerged and submerged implants in the canine mandible. J Periodontol 2000;71:1412-24. 33. Fiorellini JP, Buser D, Paquette DW, Williams RC, Haghighi D, Weber HP. A radiographic evaluation of bone healing around submerged and nonsubmerged dental implants in beagle dogs. J Periodontol 1999;70:248-54. 34. Negri B, Calvo-Guirado JL, Pardo-Zamora G, Ramirez-Fernandez MP, Delgado-Ruiz RA, Munoz-Guzon F. Peri-implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part I: a pilot study in dogs. Clin Oral Implants Res 2012;23: 228-35. 35. Mumcu E, Bilhan H, Geckili O. The influence of healing type on marginal bone levels of implants supporting mandibular overdentures: a randomized clinical study. Indian J Dent Res 2012;23:514-8. 36. Porter JA, von Fraunhofer JA. Success or failure of dental implants? A literature review with treatment considerations. Gen Dent 2005;53:423-32. quiz 433, 446. 37. el Askary AS, Meffert RM, Griffin T. Why do dental implants fail? Part II. Implant Dent 1999;8:265-77. 38. Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributing to failures of osseointegrated oral implants. (II). Etiopathogenesis. Eur J Oral Sci 1998;106:721-64. 39. Esposito M, Hirsch JM, Lekholm U, Thomsen P. Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology. Eur J Oral Sci 1998;106:527-51. 40. Cosyn J, Vandenbulcke E, Browaeys H, Van Maele G, De Bruyn H. Factors associated with failure of surface-modified implants up to four years of function. Clin Implant Dent Relat Res 2012;14:347-58. 41. Morris HF, Manz MC, Tarolli JH. Success of multiple endosseous dental implant designs to second-stage surgery across study sites. J Oral Maxillofac Surg 1997;55:76-82. 42. Lambert PM, Morris HF, Ochi S. Positive effect of surgical experience with implants on second-stage implant survival. J Oral Maxillofac Surg 1997;55: 12-8. Corresponding author: Dr Mohammad D. Al Amri Department of Prosthetic Dental Sciences College of Dentistry King Saud University PO Box 60169 Riyadh 11545 SAUDI ARABIA Email: [email protected] Copyright © 2016 by the Editorial Council for The Journal of Prosthetic Dentistry.
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SUPPLEMENTAL MATERIAL a. Lombardo G, Corrocher G, Pighi J, Faccioni F, Rovera A, Marincola M, et al. The impact of subcrestal placement on short locking-taper implants placed in posterior maxilla and mandible: a retrospective evaluation on hard and soft tissues stability after 2 years of loading. Minerva Stomatol 2014;63:391-402. (Focused question was not answered). b. Lambrecht JT, Filippi A, Kunzel AR, Schiel HJ. Long-term evaluation of submerged and nonsubmerged ITI solid-screw titanium implants: a 10-year life table analysis of 468 implants. Int J Oral Maxillofac Implants 2003;18: 826-34. (Crestal bone loss was not reported). c. Palaska I, Tsaousoglou P, Vouros I, Konstantinidis A, Menexes G. Influence of placement depth and abutment connection pattern on bone remodeling around 1-stage implants: a prospective randomized controlled clinical trial. Clin Oral Implants Res 2016;27:e47-56. (Platform switched implants were used). d. Schwarz F, Mihatovic I, Golubovich V, Schär A, Sager M, Becker J. Impact of abutment microstructure and insertion depth on crestal bone changes at nonsubmerged titanium implants with platform switch. Clin Oral Implants Res 2015;26:287-92. (Platform switched implants were used). e. Kutan-Misirlioglu E, Bolukbasi N, Yildirim-Ondur E, Ozdemir T. clinical and radiographic evaluation of marginal bone changes around platformswitching implants placed in crestal or subcrestal positions: a randomized controlled clinical trial. Clin Implant Dent Relat Res 2015;17:e364-75. (Platform switched implants were used). f. Lee J, Fiorini T, Gamborena I, Wenzel BA, Schüpbach P, Wikesjö UM, et al. Effect of platform shift/switch on crestal bone levels and mucosal profile following flapless surgery and crestal/subcrestal implant placement. Clin Implant Dent Relat Res 2016;18:73-81. g. Laster Z, Weissberg I, Kablan F. Biomechanics and peri-implantitis: The effect of a subcrestal wing-thread to decrease alveolarcrestal bone strain. theory, finite element analysis, and clinical application. Int J Oral Maxillofac Implants 2014;29:e265-71. (Focused question was not answered). h. Wenzel BA, Gamborena I, Lee J, Fiorini T, Schüpbach P, Wikesjö UM, et al. Effect of platform shift on crestal bone levels and mucosal profile following flap surgery and subcrestal implant placement in presence/absence of gap defects. Clin Implant Dent Relat Res 2016;18:217-25. i. Schwarz F, Alcoforado G, Nelson K, Schaer A, Taylor T, Beuer F, et al. Impact of implant-abutment connection, positioning of the machined collar/microgap, and platform switching on crestal bone level changes. Camlog
Al Amri
j. k.
l.
m.
n.
o.
p. q.
r.
s.
Foundation Consensus Report. Clin Oral Implants Res 2014;25:1301-3. (Focused question was not answered). Romanos GE, Aydin E, Gaertner K, Nentwig GH. Long-Term Results after Subcrestal or Crestal Placement of Delayed Loaded Implants. Clin Implant Dent Relat Res 2015;17:133-41. (Platform switched implants were used). Suaid FA, Novaes AB Jr, Queiroz AC, Muglia VA, Almeida AL, Grisi MF. Buccal bone plate remodeling after immediate implants with or without synthetic bone grafting and flapless surgery: a histomorphometric and fluorescence study in dogs. Clin Oral Implants Res 2014;25:e10-21. (Focused question was not answered). Alonso-González R, Aloy-Prósper A, Peñarrocha-Oltra D, PeñarrochaDiago MA, Peñarrocha-Diago M. Marginal bone loss in relation to platform switching implant insertion depth: An update. J Clin Exp Dent 2012;4:e173-9. (Review article). Huang B, Meng H, Piao M, Xu L, Zhang L, Zhu W. Influence of placement depth on bone remodeling around tapered internal connection implant: a clinical and radiographic study in dogs. J Periodontol 2012;83:1164-71. (Focused question was not answered). Veis A, Parissis N, Tsirlis A, Papadeli C, Marinis G, Zogakis A. Evaluation of peri-implant marginal bone loss using modified abutment connections at variouscrestal level placements. Int J Periodontics Restorative Dent 2010;30: 609-17. (Platform switched implants were used). Donovan R, Fetner A, Koutouzis T, Lundgren T. Crestal bone changes around implants with reduced abutment diameter placed non-submerged and at subcrestal positions: a 1-year radiographic evaluation. J Periodontol 2010;81:428-34. (Bone grafting was performed). Vidal R, Greenwell H, Hill M, Papageorgakopoulos G, Scheetz JP. Success rate of immediate implants placed and restored by novice operators. Implant Dent 2010;19:81-90. (Platform switched implants were used). Barros RR, Novaes AB Jr, Muglia VA, Iezzi G, Piattelli A. Influence of interimplant distances and placement depth on peri-implant bone remodeling of adjacent and immediately loaded Morse cone connection implants: a histomorphometric study in dogs. Clin Oral Implants Res 2010;21:371-8. (Focused question was not answered). Baggi L, Cappelloni I, Di Girolamo M, Maceri F, Vairo G. The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: a three-dimensional finite element analysis. J Prosthet Dent 2008;100:422-31. (Focused question was not answered). Broggini N, McManus LM, Hermann JS, Medina R, Schenk RK, Buser D, et al. Peri-implant inflammation defined by the implant-abutment interface. J Dent Res 2006;85:473-8. (Focused question was not answered).
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