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How Effective Is the Tent Screw Pole Technique Compared to Other Forms of Horizontal Ridge Augmentation?
Accepted Manuscript How Effective is the Tent-Screw Pole technique Compared to Other Forms of Horizontal Ridge Augmentation? George R. Deeb, DDS, MD, Dan Tran, DDS, Caroline K. Carrico, PhD, Erin Block, BS, Daniel M. Laskin, DDS, MS, Janina Golob Deeb, DDS, MS PII:
S0278-2391(17)30614-6
DOI:
10.1016/j.joms.2017.05.037
Reference:
YJOMS 57834
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 25 April 2017 Revised Date:
10 May 2017
Accepted Date: 31 May 2017
Please cite this article as: Deeb GR, Tran D, Carrico CK, Block E, Laskin DM, Deeb JG, How Effective is the Tent-Screw Pole technique Compared to Other Forms of Horizontal Ridge Augmentation?, Journal of Oral and Maxillofacial Surgery (2017), doi: 10.1016/j.joms.2017.05.037. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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How Effective is the Tent-Screw Pole technique Compared to Other Forms of Horizontal Ridge Augmentation? George R. Deeb, DDS, MDa, Dan Tran DDSb, Caroline K. Carrico PhDc, Erin Block BSd, Daniel M. Laskin, DDS, MSe, Janina Golob Deeb, DDS, MSf aAssociate
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Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
bResident,
Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
cAssistant
School of Dentistry, Virginia Commonwealth University, Richmond VA
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dStudent,
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Professor, Department of Research Administration. Virginia Commonwealth University. Richmond VA.
eProfessor
Emeritus, Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
fAssistant
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Professor, Department of Periodontics, School of Dentistry, Virginia Commonwealth University, Richmond VA
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How Effective is the Tent-Screw Pole Technique Compared to Other Forms of Horizontal Ridge Augmentation? Abstract:
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Purpose: The tent screw-pole technique is one of the methods available for practitioners to perform horizontal ridge augmentation to facilitate dental implant placement. The purpose of this study was to evaluate the efficacy of the tent-screw pole technique for horizontal ridge augmentation and to compare the results to the tunnel technique and open ridge augmentation.
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Patients and Methods: In this retrospective cohort study, 35 patients underwent horizontal ridge augmentation with the tent-screw pole technique, a 1:1 ratio of mineralized freeze dried bone allograft and particulate bovine hydroxyapatite, and a resorbable collagen membrane. The incidence of early wound dehiscence and membrane exposure, and the number of courses of antibiotics and postoperative visits required for their management, as well as the number of sites that subsequently had successful implant placement were recorded. These parameters were compared to those in 21 patients who had undergone horizontal ridge augmentation by the tunnel technique and 31 patients who has been treated using an open procedure and a resorbable PTFE membrane in our previous study (1).
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Results: Implant placement rate was similar among all three methods (71-97%). However, there were significant difference among the three surgical techniques and membrane exposure/wound dehiscence (p-value=0.0033), graft loss (p-value=0.0256), courses of antibiotics (p-value=0.0017), and postoperative visits (p-value=0.0043). The PTFE method consistently had the highest rate of complications, while the tent screw and tunnel techniques were comparable.
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Conclusions: All three techniques allowed a high rate of implant placement; however, the PTFE technique was consistently associated with increased postoperative complications compared to the other two methods. The tent screw technique may be more favorable than the tunnel technique in cases in which the bony deficiency is flat. Introduction:
Restoring horizontal hard tissue deficits of the alveolar ridge for implant patients is one of the most common challenges oral and maxillofacial surgeons face, and various techniques have been suggested to manage this problem. A frequently proposed method is to use barrier membranes for guided bone regeneration (GBR) (2,3). Both non-resorbable and bio-resorbable barrier membranes have been used to create separation of the graft and soft tissues and promote osteogenic cell ingrowth. (4, 5). Non-resorbable barriers include ePTFE, and high density PTFE. One of the most common complications of this technique is early (1-2 weeks) wound dehiscence and membrane
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exposure, which can lead to numerous postoperative visits to treat the graft site. Moreover, bone gain is significantly diminished with early membrane exposure (6-8). In the immediate postoperative period the site can become infected, leading to loss of the graft entirely, with morbidity, the need for additional procedures, and increased cost.
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The tunnel technique as described by Block (9,10) is an alternative method to assist in horizontal ridge augmentation. This technique is a minimally invasive, using a small incision, creating a localized subperiosteal tunnel and then introducing the graft material. It can be performed with or without the use of a resorbable collagen membrane (9,10).
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A third technique available to the surgeon is the tent screw-pole technique as described by Hempton and Le (11,12). It is an open technique in which tenting screws are placed into the defect and the bone graft is then packed around the screws before covering the defect with a resorbable collagen membrane.
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The purpose of this study was to evaluate the efficacy of the tent-screw pole technique for horizontal ridge augmentation and to compare the results to those from our previous study comparing the tunnel technique and open ridge augmentation using a PTFE membrane (11). Our hypothesis was that the tent-screw pole technique would have similar success rates compared to the tunnel technique, and would have fewer complications compared to the titanium-reinforced PTFE membrane technique.
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Patients and Methods: Study Design
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In this Institutional Review Board–approved retrospective cohort tent-screw pole technique study, a chart review was performed to find patients aged 18 years or older who had undergone horizontal ridge augmentation with this technique from November 6, 2013 to March 25, 2016 in the Department of Oral and Maxillofacial Surgery at the Virginia Commonwealth University School of Dentistry. Subjects were excluded from the study due to the following criteria: a component of vertical ridge augmentation also was performed, horizontal augmentation was combined with simultaneous implant placement, or adjunctive methods such as platelet rich plasma or bone morphogenic protein had been used. All patients included in the study had been assessed preoperatively using cone beam computed tomography (CBCT) to characterize ridge topography and for treatment planning of the grafting procedure. Surgical Techniques
Tent-Screw Pole All procedures were performed under local anesthesia with or without intravenous sedation by senior level oral and maxillofacial surgery residents under direct supervision by the director of the graduate implant program. A crestal incision with vertical releases was made and a full thickness buccal mucoperiosteal flap was elevated. Two to 4 titanium
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screws (Pro-fix™ Tenting Screws, Osteogenics) were placed in the alveolar ridge deficiency area with approximately 3 to 6 mm of the screw exposed above the alveolus, depending on the depth of the defect. (Figure 1). The screws were 1.5 mm wide, with a self-drilling tip, polished neck, and broad head, and were used to maintain space for the graft under the resorbable membrane. A particulate bone graft consisting of a 1:1 mixture of mineralized freeze-dried bone allograft (Puros, Zimmer Dental, Warsaw, IN,) and particulate bovinederived hydroxyapatite (Geistlich Bio-Oss, Geistlich Pharma North America, Princeton, NJ) was placed into the site until only the surface of the screws was visible (Figure 2). A resorbable membrane (Bioguide, Geistlich Pharma North America, Princeton, NJ) was then placed over the screws and grafted site without retention with screws or tacks (Figure 3). After creating a periosteal release high in the vestibule for tension-free closure, the wound was closed using PTFE sutures (Figure 4).
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Tunnel Technique (1) The tunnel ridge augmentations were performed via a vertical incision made just inferior to the mucogingival margin approximately 1 cm distal to the proposed graft site, followed by creation of a subperiosteal tunnel for containment of the particulate grafting material. The subperiosteal dissection was limited to the confines of the area to be augmented, and care was taken to avoid damage to the mental nerve. Once the tunnel was prepared, the graft material, consisting of a 1:1 mix of mineralized freeze-dried bone allograft (Puros; Zimmer Dental) and particulate bovine-derived hydroxyapatite (Geistlich Bio-Oss) was then carefully injected with a modified tuberculin syringe (Figure 5).
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Open PTFE Technique (1) For the open technique, a crestal incision bisecting the attached mucosa was made and buccal and lingual full-thickness mucoperiosteal flaps were reflected. A titanium-reinforced PTFE (Cytoplast, Osteogenics) membrane was secured on the palatal aspect of the maxilla or lingual aspect of the mandible first with at least 1 titanium screw. The bone graft, consisting of a 1:1 mix of mineralized freeze-dried bone allograft (Puros: Zimmer Dental) and particulate bovine-derived hydroxyapatite (Geistlich Bio-Oss;), was then placed and the membrane folded over the graft and secured on the buccal aspect of the ridge with 2 titanium screws (Figure 6). A minimum of 3 titanium screws were used in each case.
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All patients, irrespective of surgical technique, were given a preoperative dose of 2 grams of amoxicillin orally or clindamycin 900 mg intravenously and were continued on amoxicillin 500mg every 8 hours for 1 week postoperatively. Penicillin-allergic patients received a course of clindamycin 300mg every 6 hours for 1 week. Patients were seen for scheduled follow-up visits at 1 week, 1 month, and 6 months postoperatively. Those patients with dehisced graft sites or infection were seen on an as-needed basis. Infected patients were first treated with a course of antibiotics for an additional 1 week (PO amoxicillin 500 mg TID or clindamycin 300 mg QID). If the infection did not resolve after this course of antibiotics, the tacking screws were removed and any graft material that appeared to be infected or was not consolidated was debrided. Patients with dehiscence in the absence of infection were managed with chlorhexidine and wound cleansing.
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All patients underwent CBCT at 6 months postoperatively and the bone graft sites were assessed for implant placement. Success of the augmentation was determined based on consolidation of the graft material at the site and the ability to have an implant of appropriate size for the specific site placed without further grafting. Removal of all the tenting screws was done via the same flap exposure used for implant placement. Data Analysis
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Results:
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The findings in this study were compared to those from our previous studies in which a non-resorbable PTFE membrane or the tunnel technique was used for horizontal ridge augmentation (1). Based on our hypothesis, the primary outcome was whether an implant was placed successfully. Secondary outcomes measured in the study were whether wound dehiscence/membrane exposure occurred, whether any of the graft was lost, the number of courses of antibiotics the patient was prescribed, and the number of postoperative visits. The primary hypothesis and secondary hypotheses regarding categorical variables (wound dehiscence, graft loss) were tested using generalized linear models with binary outcome and complementary log-log link to determine if there were differences among the three methods. For the secondary outcomes that were continuous in nature, Poisson regression was used. This method determined if the number of courses of antibiotics and the number of postoperative visits were significantly different among the three methods. All post hoc pairwise comparisons were adjusted for multiple comparisons with Tukey’s adjustment. All analyses were performed in SAS EG v.6.1, with a significance level of 0.05.
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Thirty-five patients treated with the tent-screw pole technique met the inclusion criteria. These were compared with thirty-one patients treated by open augmentation with nonresorbable (PTFE) membranes and twenty patients treated with the tunnel technique previously reported (12) (Table1). Primary Research Question: Implant Placement Rate.
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Within six months after bone grafting, 18 of the 21 patients (86%) treated with the tunnel technique, 22 of the 31 patients (71%) treated with the open technique, and 33 of the 35 (97%) patients treated with tent screws had sufficient alveolar ridge width for successful implant placement. These results represent a slight difference in implant placement rates, favoring tent screws (p =0.0536, Table 1). The implant placement rate was marginally significantly higher for the tent screw method than the PTFE method (adjusted pvalue=0.0593). The difference in placement rate was not significantly different between the PTFE and tunnel methods (adjusted p-value=0.4583) and between the tunnel and tent screw procedures (adjusted p-value=0.3347). Secondary Research Question: Increased Complications.
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There were significant differences in all complications recorded among the three methods (membrane exposure/wound dehiscence: p-value=0.0033, graft loss: p-value=0.0256, antibiotic courses: p-value= 0.0017, postoperative visits: p-value=0.0043, Table 1). The number of ridge augmentations that developed dehiscence or membrane exposure was significantly greater in the PTFE group than in the tunnel (adjusted p-value=0.0447) and tent screw groups (adjusted p-value=0.0027), but there was no difference between the latter two groups (adjusted p-value =0.7458). PTFE use was also associated with a higher rate of graft loss than tent screws (adjusted p-value= 0.0275). The rate of graft loss for the tunnel technique was not significantly different from the PTFE technique (adjusted pvalue=0.3205) or use of tent screws (adjusted p-value=0.5033).
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Patients treated with the PTFE method received significantly more courses of antibiotics than those with tent screws (adjusted p-value=0.0015). The difference in number of antibiotic courses was not significantly different between the tunnel and PTFE group (adjusted p-value=0.2665), or tent screw group (adjusted p-value=0.2440). Patients treated with the open PTFE method also required significantly more postoperative visits than those treated with the tunnel technique (adjusted p-value=0.0123) or tent screws (adjusted p-value=0.0284). However, there was no difference in postoperative visits between the tunnel and the tent screw groups ( p=0.7462). Discussion:
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The purpose of this study was to evaluate the clinical outcomes of using the tent-screw pole technique for horizontal ridge augmentation to facilitate dental implant placement. We hypothesized that the tent-screw pole technique group would have similar graft success rates compared to the tunnel technique, and would have less wound dehiscence or membrane exposure, lower numbers of required postoperative visits, and less courses of required antibiotics compared to the titanium-reinforced PTFE membrane technique group. The findings of our analysis confirmed this hypothesis.
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Although the tent-screw technique and the tunnel technique provided relatively similar results, the fact that the latter method involves less complex surgery and is more cost effective (Table 2) would generally favor its use. However, this could depend on the contour of the involved area of bony deficiency. Whereas in situations in which the deficiency is C-shaped (Figure.7) the graft placed by the tunnel technique is well confined, in regions where the defect is flat such grafts may tend to migrate. Because the tent screw method involves the use of an adjunctive resorbable membrane, this does not occur. Thus, this method may be more favorable in such situations.
Figure Captions:
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Figure 1. Tenting screws placed in the defect.
Figure 2. Bone graft material applied to the defect to the height of the tenting screws.
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Figure 3. Application of a resorbable collagen membrane over the tenting screws and bone graft material prior to wound closure. Figure 4. Tension free wound closure with PTFE sutures after a periosteal release is performed.
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Figure 5. Modified tuberculin syringe being used to perform a ridge augmentation via the tunnel technique. Figure 6. Titanium reinforced PTFE membrane being held in place by tacking screws in the open PTFE method.
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Figure 7. A “C” shaped ridge defect profile (red line) suitable for tunnel grafting. References:
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1. Deeb GR, Wilson GH, Carrico CK, Zafar U, Laskin DM, Golob Deeb J. "Is the Tunnel Technique More Effective Than Open Augmentation with a Titanium-Reinforced Polytetrafluoroethylene Membrane for Horizontal Ridge Augmentation?" Journal of Oral and Maxillofacial Surgery 74.9 (2016): 1752-756 2. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: A clinical and radiographic 12-month prospective study. Int J Periodont Restorat Dent. 2003, 23, 313-323
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3. Dahlin C, Gottlow J, Linde A, Nyman S. Healing of maxillary and mandibular bone defects using a membrane technique. An experimental study in monkeys. Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. 1990;24:13-19.
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4. Buser D, Dula K, Belser U, et al. Localized ridge augmentation using guided bone regeneration. 1. Surgical procedure in the maxilla. International Journal Periodontics Restorative Dentistry 1993;13:29-45. 5. Buser D, Dula K, Belser UC, et al. Localized ridge augmentation using guided bone regeneration. II. Surgical procedure in the mandible. International Journal of Periodontics and Restorative Dentistry, 1995;15:10-29. 6. McAllister BS, Haghighat K. Bone augmentation techniques. Journal of Periodontology 2007;78:377-396.
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7. Simion M, Baldoni M, Rossi P , et al. A comparative study of the effectiveness of e-PTFE membranes with and without early exposure during the healing period. Int J Periodont Restorat Dent. 1994;14:166–80.
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8. Machtei, E E. The effect of membrane exposure on the outcome of regenerative procedures in humans: a meta-analysis. Journal of periodontology 2001, 72, 512-5166. 9. Block, Michael S. ; Kelley, Brian Horizontal Posterior Ridge Augmentation: The Use of a Collagen Membrane Over a Bovine Particulate Graft: Technique Note. Journal of Oral and Maxillofacial Surgery, 2013,71,1513-1519. 10. Block, Michael S. Color Atlas of Dental Implant Surgery. 3 ed. Maryland Heights, Missouri: Saunders Elsevier, 2011.
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11. Tj, Hempton, and Fugazzotto Pa. "Ridge Augmentation Utilizing Guided Tissue Regeneration, Titanium Screws, Freeze-dried Bone, and Tricalcium Phosphate." Implant Dentistry 3.1 (1994): 58.
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12. Le, Bach, Michael D. Rohrer, and Hari S. Prassad. "Screw “Tent-Pole” Grafting Technique for Reconstruction of Large Vertical Alveolar Ridge Defects Using Human Mineralized Allograft for Implant Site Preparation." Journal of Oral and Maxillofacial Surgery 68.2 (2010): 428-35
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Table 1: Study Outcome Measures by Surgical Technique Primary Predictor: Surgical Technique
Sample Size (n) Primary Outcome Variable Implant placed (n, %)
22, 71%
A
Tent Screws P-value (TS) 35
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Open (PTFE) 31
Tunnel
21
18, 86% A
33, 97%
A
A
B
B
0.0033
A,B
B
0.0256
B
0.0017
B
0.0043
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Secondary Outcome Variables Membrane Exposed/Wound 16, 52% 4, 19% 4, 11% Dehiscence (n, %) Graft Loss (n, %) 12, 39% 4, 19% 3, 9% Courses of Antibiotics (median, 1, (12, (1- 5) 1 (0-2) (range)) 3) Postoperative Visits (median, (range)) 3, (1- 6) 1, (1- 3) 2 (1-4) *Items marked with different letters are significantly different (Adjusted P-value<0.05) A
A,B
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A
0.0536
B
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Tent ScrewPole Tunnel Technique Open PTFE
11%
Eventual implant placement 97%
19%
86%
52%
71%
Technical difficulty More difficult easier More difficult
Postoperative Visits (Median) 2
Antibiotic Courses (Median) 1
Materials Cost Average $406.30
1
1
$185.60
3
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Membrane exposure
2
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Technique
$497.50
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S0278-2391(17)30614-6
DOI:
10.1016/j.joms.2017.05.037
Reference:
YJOMS 57834
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 25 April 2017 Revised Date:
10 May 2017
Accepted Date: 31 May 2017
Please cite this article as: Deeb GR, Tran D, Carrico CK, Block E, Laskin DM, Deeb JG, How Effective is the Tent-Screw Pole technique Compared to Other Forms of Horizontal Ridge Augmentation?, Journal of Oral and Maxillofacial Surgery (2017), doi: 10.1016/j.joms.2017.05.037. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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How Effective is the Tent-Screw Pole technique Compared to Other Forms of Horizontal Ridge Augmentation? George R. Deeb, DDS, MDa, Dan Tran DDSb, Caroline K. Carrico PhDc, Erin Block BSd, Daniel M. Laskin, DDS, MSe, Janina Golob Deeb, DDS, MSf aAssociate
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Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
bResident,
Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
cAssistant
School of Dentistry, Virginia Commonwealth University, Richmond VA
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dStudent,
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Professor, Department of Research Administration. Virginia Commonwealth University. Richmond VA.
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Emeritus, Department of Oral and Maxillofacial Surgery, School of Dentistry, Virginia Commonwealth University, Richmond VA
fAssistant
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Professor, Department of Periodontics, School of Dentistry, Virginia Commonwealth University, Richmond VA
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How Effective is the Tent-Screw Pole Technique Compared to Other Forms of Horizontal Ridge Augmentation? Abstract:
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Purpose: The tent screw-pole technique is one of the methods available for practitioners to perform horizontal ridge augmentation to facilitate dental implant placement. The purpose of this study was to evaluate the efficacy of the tent-screw pole technique for horizontal ridge augmentation and to compare the results to the tunnel technique and open ridge augmentation.
M AN U
SC
Patients and Methods: In this retrospective cohort study, 35 patients underwent horizontal ridge augmentation with the tent-screw pole technique, a 1:1 ratio of mineralized freeze dried bone allograft and particulate bovine hydroxyapatite, and a resorbable collagen membrane. The incidence of early wound dehiscence and membrane exposure, and the number of courses of antibiotics and postoperative visits required for their management, as well as the number of sites that subsequently had successful implant placement were recorded. These parameters were compared to those in 21 patients who had undergone horizontal ridge augmentation by the tunnel technique and 31 patients who has been treated using an open procedure and a resorbable PTFE membrane in our previous study (1).
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Results: Implant placement rate was similar among all three methods (71-97%). However, there were significant difference among the three surgical techniques and membrane exposure/wound dehiscence (p-value=0.0033), graft loss (p-value=0.0256), courses of antibiotics (p-value=0.0017), and postoperative visits (p-value=0.0043). The PTFE method consistently had the highest rate of complications, while the tent screw and tunnel techniques were comparable.
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Conclusions: All three techniques allowed a high rate of implant placement; however, the PTFE technique was consistently associated with increased postoperative complications compared to the other two methods. The tent screw technique may be more favorable than the tunnel technique in cases in which the bony deficiency is flat. Introduction:
Restoring horizontal hard tissue deficits of the alveolar ridge for implant patients is one of the most common challenges oral and maxillofacial surgeons face, and various techniques have been suggested to manage this problem. A frequently proposed method is to use barrier membranes for guided bone regeneration (GBR) (2,3). Both non-resorbable and bio-resorbable barrier membranes have been used to create separation of the graft and soft tissues and promote osteogenic cell ingrowth. (4, 5). Non-resorbable barriers include ePTFE, and high density PTFE. One of the most common complications of this technique is early (1-2 weeks) wound dehiscence and membrane
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exposure, which can lead to numerous postoperative visits to treat the graft site. Moreover, bone gain is significantly diminished with early membrane exposure (6-8). In the immediate postoperative period the site can become infected, leading to loss of the graft entirely, with morbidity, the need for additional procedures, and increased cost.
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The tunnel technique as described by Block (9,10) is an alternative method to assist in horizontal ridge augmentation. This technique is a minimally invasive, using a small incision, creating a localized subperiosteal tunnel and then introducing the graft material. It can be performed with or without the use of a resorbable collagen membrane (9,10).
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A third technique available to the surgeon is the tent screw-pole technique as described by Hempton and Le (11,12). It is an open technique in which tenting screws are placed into the defect and the bone graft is then packed around the screws before covering the defect with a resorbable collagen membrane.
M AN U
The purpose of this study was to evaluate the efficacy of the tent-screw pole technique for horizontal ridge augmentation and to compare the results to those from our previous study comparing the tunnel technique and open ridge augmentation using a PTFE membrane (11). Our hypothesis was that the tent-screw pole technique would have similar success rates compared to the tunnel technique, and would have fewer complications compared to the titanium-reinforced PTFE membrane technique.
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Patients and Methods: Study Design
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In this Institutional Review Board–approved retrospective cohort tent-screw pole technique study, a chart review was performed to find patients aged 18 years or older who had undergone horizontal ridge augmentation with this technique from November 6, 2013 to March 25, 2016 in the Department of Oral and Maxillofacial Surgery at the Virginia Commonwealth University School of Dentistry. Subjects were excluded from the study due to the following criteria: a component of vertical ridge augmentation also was performed, horizontal augmentation was combined with simultaneous implant placement, or adjunctive methods such as platelet rich plasma or bone morphogenic protein had been used. All patients included in the study had been assessed preoperatively using cone beam computed tomography (CBCT) to characterize ridge topography and for treatment planning of the grafting procedure. Surgical Techniques
Tent-Screw Pole All procedures were performed under local anesthesia with or without intravenous sedation by senior level oral and maxillofacial surgery residents under direct supervision by the director of the graduate implant program. A crestal incision with vertical releases was made and a full thickness buccal mucoperiosteal flap was elevated. Two to 4 titanium
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screws (Pro-fix™ Tenting Screws, Osteogenics) were placed in the alveolar ridge deficiency area with approximately 3 to 6 mm of the screw exposed above the alveolus, depending on the depth of the defect. (Figure 1). The screws were 1.5 mm wide, with a self-drilling tip, polished neck, and broad head, and were used to maintain space for the graft under the resorbable membrane. A particulate bone graft consisting of a 1:1 mixture of mineralized freeze-dried bone allograft (Puros, Zimmer Dental, Warsaw, IN,) and particulate bovinederived hydroxyapatite (Geistlich Bio-Oss, Geistlich Pharma North America, Princeton, NJ) was placed into the site until only the surface of the screws was visible (Figure 2). A resorbable membrane (Bioguide, Geistlich Pharma North America, Princeton, NJ) was then placed over the screws and grafted site without retention with screws or tacks (Figure 3). After creating a periosteal release high in the vestibule for tension-free closure, the wound was closed using PTFE sutures (Figure 4).
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Tunnel Technique (1) The tunnel ridge augmentations were performed via a vertical incision made just inferior to the mucogingival margin approximately 1 cm distal to the proposed graft site, followed by creation of a subperiosteal tunnel for containment of the particulate grafting material. The subperiosteal dissection was limited to the confines of the area to be augmented, and care was taken to avoid damage to the mental nerve. Once the tunnel was prepared, the graft material, consisting of a 1:1 mix of mineralized freeze-dried bone allograft (Puros; Zimmer Dental) and particulate bovine-derived hydroxyapatite (Geistlich Bio-Oss) was then carefully injected with a modified tuberculin syringe (Figure 5).
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Open PTFE Technique (1) For the open technique, a crestal incision bisecting the attached mucosa was made and buccal and lingual full-thickness mucoperiosteal flaps were reflected. A titanium-reinforced PTFE (Cytoplast, Osteogenics) membrane was secured on the palatal aspect of the maxilla or lingual aspect of the mandible first with at least 1 titanium screw. The bone graft, consisting of a 1:1 mix of mineralized freeze-dried bone allograft (Puros: Zimmer Dental) and particulate bovine-derived hydroxyapatite (Geistlich Bio-Oss;), was then placed and the membrane folded over the graft and secured on the buccal aspect of the ridge with 2 titanium screws (Figure 6). A minimum of 3 titanium screws were used in each case.
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All patients, irrespective of surgical technique, were given a preoperative dose of 2 grams of amoxicillin orally or clindamycin 900 mg intravenously and were continued on amoxicillin 500mg every 8 hours for 1 week postoperatively. Penicillin-allergic patients received a course of clindamycin 300mg every 6 hours for 1 week. Patients were seen for scheduled follow-up visits at 1 week, 1 month, and 6 months postoperatively. Those patients with dehisced graft sites or infection were seen on an as-needed basis. Infected patients were first treated with a course of antibiotics for an additional 1 week (PO amoxicillin 500 mg TID or clindamycin 300 mg QID). If the infection did not resolve after this course of antibiotics, the tacking screws were removed and any graft material that appeared to be infected or was not consolidated was debrided. Patients with dehiscence in the absence of infection were managed with chlorhexidine and wound cleansing.
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All patients underwent CBCT at 6 months postoperatively and the bone graft sites were assessed for implant placement. Success of the augmentation was determined based on consolidation of the graft material at the site and the ability to have an implant of appropriate size for the specific site placed without further grafting. Removal of all the tenting screws was done via the same flap exposure used for implant placement. Data Analysis
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Results:
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The findings in this study were compared to those from our previous studies in which a non-resorbable PTFE membrane or the tunnel technique was used for horizontal ridge augmentation (1). Based on our hypothesis, the primary outcome was whether an implant was placed successfully. Secondary outcomes measured in the study were whether wound dehiscence/membrane exposure occurred, whether any of the graft was lost, the number of courses of antibiotics the patient was prescribed, and the number of postoperative visits. The primary hypothesis and secondary hypotheses regarding categorical variables (wound dehiscence, graft loss) were tested using generalized linear models with binary outcome and complementary log-log link to determine if there were differences among the three methods. For the secondary outcomes that were continuous in nature, Poisson regression was used. This method determined if the number of courses of antibiotics and the number of postoperative visits were significantly different among the three methods. All post hoc pairwise comparisons were adjusted for multiple comparisons with Tukey’s adjustment. All analyses were performed in SAS EG v.6.1, with a significance level of 0.05.
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Thirty-five patients treated with the tent-screw pole technique met the inclusion criteria. These were compared with thirty-one patients treated by open augmentation with nonresorbable (PTFE) membranes and twenty patients treated with the tunnel technique previously reported (12) (Table1). Primary Research Question: Implant Placement Rate.
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Within six months after bone grafting, 18 of the 21 patients (86%) treated with the tunnel technique, 22 of the 31 patients (71%) treated with the open technique, and 33 of the 35 (97%) patients treated with tent screws had sufficient alveolar ridge width for successful implant placement. These results represent a slight difference in implant placement rates, favoring tent screws (p =0.0536, Table 1). The implant placement rate was marginally significantly higher for the tent screw method than the PTFE method (adjusted pvalue=0.0593). The difference in placement rate was not significantly different between the PTFE and tunnel methods (adjusted p-value=0.4583) and between the tunnel and tent screw procedures (adjusted p-value=0.3347). Secondary Research Question: Increased Complications.
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There were significant differences in all complications recorded among the three methods (membrane exposure/wound dehiscence: p-value=0.0033, graft loss: p-value=0.0256, antibiotic courses: p-value= 0.0017, postoperative visits: p-value=0.0043, Table 1). The number of ridge augmentations that developed dehiscence or membrane exposure was significantly greater in the PTFE group than in the tunnel (adjusted p-value=0.0447) and tent screw groups (adjusted p-value=0.0027), but there was no difference between the latter two groups (adjusted p-value =0.7458). PTFE use was also associated with a higher rate of graft loss than tent screws (adjusted p-value= 0.0275). The rate of graft loss for the tunnel technique was not significantly different from the PTFE technique (adjusted pvalue=0.3205) or use of tent screws (adjusted p-value=0.5033).
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Patients treated with the PTFE method received significantly more courses of antibiotics than those with tent screws (adjusted p-value=0.0015). The difference in number of antibiotic courses was not significantly different between the tunnel and PTFE group (adjusted p-value=0.2665), or tent screw group (adjusted p-value=0.2440). Patients treated with the open PTFE method also required significantly more postoperative visits than those treated with the tunnel technique (adjusted p-value=0.0123) or tent screws (adjusted p-value=0.0284). However, there was no difference in postoperative visits between the tunnel and the tent screw groups ( p=0.7462). Discussion:
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The purpose of this study was to evaluate the clinical outcomes of using the tent-screw pole technique for horizontal ridge augmentation to facilitate dental implant placement. We hypothesized that the tent-screw pole technique group would have similar graft success rates compared to the tunnel technique, and would have less wound dehiscence or membrane exposure, lower numbers of required postoperative visits, and less courses of required antibiotics compared to the titanium-reinforced PTFE membrane technique group. The findings of our analysis confirmed this hypothesis.
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Although the tent-screw technique and the tunnel technique provided relatively similar results, the fact that the latter method involves less complex surgery and is more cost effective (Table 2) would generally favor its use. However, this could depend on the contour of the involved area of bony deficiency. Whereas in situations in which the deficiency is C-shaped (Figure.7) the graft placed by the tunnel technique is well confined, in regions where the defect is flat such grafts may tend to migrate. Because the tent screw method involves the use of an adjunctive resorbable membrane, this does not occur. Thus, this method may be more favorable in such situations.
Figure Captions:
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Figure 1. Tenting screws placed in the defect.
Figure 2. Bone graft material applied to the defect to the height of the tenting screws.
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Figure 3. Application of a resorbable collagen membrane over the tenting screws and bone graft material prior to wound closure. Figure 4. Tension free wound closure with PTFE sutures after a periosteal release is performed.
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Figure 5. Modified tuberculin syringe being used to perform a ridge augmentation via the tunnel technique. Figure 6. Titanium reinforced PTFE membrane being held in place by tacking screws in the open PTFE method.
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Figure 7. A “C” shaped ridge defect profile (red line) suitable for tunnel grafting. References:
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1. Deeb GR, Wilson GH, Carrico CK, Zafar U, Laskin DM, Golob Deeb J. "Is the Tunnel Technique More Effective Than Open Augmentation with a Titanium-Reinforced Polytetrafluoroethylene Membrane for Horizontal Ridge Augmentation?" Journal of Oral and Maxillofacial Surgery 74.9 (2016): 1752-756 2. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: A clinical and radiographic 12-month prospective study. Int J Periodont Restorat Dent. 2003, 23, 313-323
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3. Dahlin C, Gottlow J, Linde A, Nyman S. Healing of maxillary and mandibular bone defects using a membrane technique. An experimental study in monkeys. Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. 1990;24:13-19.
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4. Buser D, Dula K, Belser U, et al. Localized ridge augmentation using guided bone regeneration. 1. Surgical procedure in the maxilla. International Journal Periodontics Restorative Dentistry 1993;13:29-45. 5. Buser D, Dula K, Belser UC, et al. Localized ridge augmentation using guided bone regeneration. II. Surgical procedure in the mandible. International Journal of Periodontics and Restorative Dentistry, 1995;15:10-29. 6. McAllister BS, Haghighat K. Bone augmentation techniques. Journal of Periodontology 2007;78:377-396.
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7. Simion M, Baldoni M, Rossi P , et al. A comparative study of the effectiveness of e-PTFE membranes with and without early exposure during the healing period. Int J Periodont Restorat Dent. 1994;14:166–80.
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8. Machtei, E E. The effect of membrane exposure on the outcome of regenerative procedures in humans: a meta-analysis. Journal of periodontology 2001, 72, 512-5166. 9. Block, Michael S. ; Kelley, Brian Horizontal Posterior Ridge Augmentation: The Use of a Collagen Membrane Over a Bovine Particulate Graft: Technique Note. Journal of Oral and Maxillofacial Surgery, 2013,71,1513-1519. 10. Block, Michael S. Color Atlas of Dental Implant Surgery. 3 ed. Maryland Heights, Missouri: Saunders Elsevier, 2011.
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11. Tj, Hempton, and Fugazzotto Pa. "Ridge Augmentation Utilizing Guided Tissue Regeneration, Titanium Screws, Freeze-dried Bone, and Tricalcium Phosphate." Implant Dentistry 3.1 (1994): 58.
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12. Le, Bach, Michael D. Rohrer, and Hari S. Prassad. "Screw “Tent-Pole” Grafting Technique for Reconstruction of Large Vertical Alveolar Ridge Defects Using Human Mineralized Allograft for Implant Site Preparation." Journal of Oral and Maxillofacial Surgery 68.2 (2010): 428-35
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Table 1: Study Outcome Measures by Surgical Technique Primary Predictor: Surgical Technique
Sample Size (n) Primary Outcome Variable Implant placed (n, %)
22, 71%
A
Tent Screws P-value (TS) 35
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Open (PTFE) 31
Tunnel
21
18, 86% A
33, 97%
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A
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B
0.0033
A,B
B
0.0256
B
0.0017
B
0.0043
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Secondary Outcome Variables Membrane Exposed/Wound 16, 52% 4, 19% 4, 11% Dehiscence (n, %) Graft Loss (n, %) 12, 39% 4, 19% 3, 9% Courses of Antibiotics (median, 1, (12, (1- 5) 1 (0-2) (range)) 3) Postoperative Visits (median, (range)) 3, (1- 6) 1, (1- 3) 2 (1-4) *Items marked with different letters are significantly different (Adjusted P-value<0.05) A
A,B
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0.0536
B
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Tent ScrewPole Tunnel Technique Open PTFE
11%
Eventual implant placement 97%
19%
86%
52%
71%
Technical difficulty More difficult easier More difficult
Postoperative Visits (Median) 2
Antibiotic Courses (Median) 1
Materials Cost Average $406.30
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$185.60
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$497.50
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