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Periodontal healing after impacted lower third molar surgery in adolescents and adults
Periodontal healing after impacted lower third molar surgery in adolescents and adults
Carl F, Kugelberg, UIf Ahlstr~m, Sune Ericson, Anders Hugoson, Sven Kvint institute for Postgraduate Dental Education, J6nk6ping, and Department of Oral Surgery, University of Gfteborg, G6teborg, Sweden
A prospectivestudy C. E Kugelberg, U. Ahlstrdm, S. Ericson, A. Hugoson, S. Kvint: Periodontal healing after impacted lower third molar surgery in adolescents and adults. A prospective study. Int. J. Oral Maxillofac. Surg. 1991; 20: 18-24. Abstract. The effects of impacted lower 3rd molar surgery on periodontal tissues in the adjacent 2nd molar area have been investigated in a prospective study comprising 176 cases from 2 age groups: _<20 years (n = 93) and -> 30 years (n = 83), respectively. The preoperative and 1-year postoperative examinations included both clinical and radiographic variables. All patients were subjected to a standardized surgical procedure and optimal plaque control pre-, intra- and postoperatively. Early removal of impacted lower 3rd molars with large angulation and close positional relationship to the adjacent 2nd molar proved to have a beneficial effect on periodontal health.
Third molar removals may result in intrabony defects on the distal surface of the 2nd molar 3,7,11,18,21,28. In a retrospective study KUGELBERGet alJ 3 demonstrated that, 2 years after impacted lower 3rd molar surgery, 32.1% of the cases showed intrabony defects _>4 mm deep on the distal surface of the adjacent 2nd molar. In individuals _<25 years of age almost 50% of the intrabony defects _>4 mm deep at surgery showed periodontal healing 2 years postoperatively, while in only a few per cent of those 26 years or older was healing acceptable. Similar results were achieved by AsH et al. 3 and MARMARY et al. 18. They found that failures in the bone healing process after lower 3rd molar surgery occurred in 3% of individuals aged 20-29 years compared with 21% of those aged 30-50 years. The importance of age was emphasised by KUGELBERG 12 in a further retrospective study, where the long-term effects of impacted lower 3rd molar surgery on periodontal tissues were investigated. At the reexamination 4 years postoperatively, the intrabony defects of nearly 50% of the subjects _<25 years old had improved since the examination 2 years after surgery. In subjects >_26 years
old improvement was only seen in 15% of the cases. Four years after 3rd molar removal, 4.2% of the subjects aged _<25 years showed intrabony defects exceeding 4 mm, compared with 44.4% in the group aged >26 years. It can be inferred from clinical experience that morbidity of the periodontal tissues following impacted lower 3'rd molar surgery may be reduced if they are removed at an early age. In a multiple regression analysis KUGELBERG et al. 15 found that, apart from the extent of preoperative damage to the tissues surrounding the adjacent 2nd molar, the age of the patient at the time of surgery was the most important variable in explaining the variance in postoperative intrabony defects. The aims of this investigation were: 1) to perform a prospective clinical study which compares the periodontal healing after impacted lower 3rd molar surgery under optimal oral hygiene conditions between two different age groups; and 2) to study the importance of some anatomical and pathophysiological variables on the periodontal healing, such as the sagittal inclination of the impacted 3rd molar and its positional relationship to the
Key words: third molar; periodontal healing; intrabony defects. Accepted for publication 3 September 1990
adjacent 2nd molar, the presence of a pathologically widened follicle and resorption of the 2nd molar root.
Material and methods The study comprised 118 patients referred for removal of 176 mandibular 3rd molars (M3). A restricted randomisation was made in order to obtain 2 samples equal in size from 2 age groups: <20 years (n=57) and ->30 years (n=61), respectively. Of a total of 176 3rd molars, 93 molars were from individuals < 20 years and 83 were from individuals ->30 years (Table 1). No significant difference existed in the distribution of males and females in the 2 age groups. The distributions
Table 1. Distribution of the 176 lower 3rd molars according to the age groups and sex of the patients Age group _<20 years Males Females Total Mean (years) SD Range (years)
Age group _>30 years
n
%
n
%
47 46 93
50.5 49.5 100.0
38 45 83
45.8 54.2 100.0
19.3 0.95 16-20
36.7 5.16 30-54
Age groups <20 vs age group _>30 (total): NS.
Periodontal healing and third molars concerning degree of impaction, sagittal inclination and positional relationship to the adjacent 2nd molar were also similar in both age groups. The following inclusion criteria were used: I. Patient willing to participate. 2. Preoperative history proving good general health. 3. Pre- and postoperative examinations, including both clinical and radiographic variables. Clinical examination Prior to 3rd molar removal the patients were examined and a general medical history was taken, including smoking habits, menstrual cycle and use o f oral contraceptives. Anamnestic information concerning previous difficulties or infections in the 3rd molar region was also recorded. The clinical examination was carried out on all 4 tooth surfaces of the 1st and 2nd molars adjacent to the extraction site. Assessments were made regarding the oral hygiene standard, gingival condition and periodontal tissue breakdown in terms of increased probing depths and intrabony defects. Baseline examination comprised the following variables: 1. Plaque Index 25 (PLI). A PLI score of 0-1 corresponded to no or not visible plaque and a PLI score of ~ 3 corresponded to visible plaque. 2. Gingival Index 17 (GI). A GI score of ~ 1 corresponded to healthy gingiva or slight inflammation and a GI score of 2-3 represented moderate changes in texture and colour and/or bleeding on probing. 3. Probing depth (PD). Probing depths were measured with a periodontal probe (Marquis*). Measurements were made to the nearest m m from the free gingival margin to the bottom of the pocket, distance AC in Fig. 1. Only probing depths exceeding 3 mm were recorded. When presenting probing depth measurements, the results have been grouped into pocket depths _>6 mm and _>7 mm. The re-examination took place 1 y e a r a f t e r surgical treatment and included the same clinical and radiographic variables as were used preoperatively.
quis) with the handle cut off served as an indicator. The final positioning of the probe was not assessed until the probe had been moved along the entire distal surface to reach the deepest part. During radiography, the indicator was placed in firm osseous contact. The intra-oral X-ray films were taken first with, and then without, the indicator (Fig.
2). All the measurements on the radiographs were performed at the end of the study. The radiographic material was studied on a horizontal illuminator with diffuse white light, which was masked according to the area of the mounted radiographs. The images were analysed with the aid of observation binoculars according to MATTSSONtg. The following variables were evaluated: 1. Proximal bone level 6 (BL). A transparent plastic ruler with 10 equidistant divisions was placed over the radiograph to estimate the bone level in 10ths of the total length of the tooth. The measurements were recorded in increments of half a division and multiplied by 10. 2. Intrabony defect (IBD). The depth of the intrabony defect was obtained by measuring the distance between the cemento-enamel junction and the bottom of the pocket, as indicated by the probe (distance BD in Fig. 1), with the aid of a transparent plastic ruler graduated in mm. Assessments were also made regarding the sagittal inclination of the 3rd molar, its state
of eruption and contact relationship to the adjacent 2nd molar, pathologically widened follicle M3 and root resorption M2 distal. Preoperative treatment On the operation day, prior to surgery, the 1st and 2nd molars on the extraction site were polished with a rubber cup and an abrasive paste. After the tooth cleaning the patients rinsed their mouths with a solution of 0.2% chlorhexidine digluconate (Hibitane ® Dental 0.2%, ICI). Surgical procedure The 3rd molar removals in women were carried out around the 14th day of the menstrual cycle2°. The patients were treated under aseptic conditions using local anaesthesia (3.6 ml Xylocaine ® adrenaline 20 mg/ml, ASTRA; adrenaline 12.5 #g/ml). A standardised surgical technique was used with a single incision for reflection of an envelope flap as described by SZMYD27. Ostectomy and sectioning were performed with a low-speed rotary instrument under constant irrigation with sterile saline. After removal of the tooth, the extraction socket was carefully cleansed, including removal o f follicular remnants and granulation tissue, and thorough saline lavage. The • time taken for the surgical procedure was measured in minutes from the first incision to the first suture. Postoperative treatment
A
Radiographic examination The radiographic recordings were performed under standardised conditions. Details of the radiographic technique have been previously published t4. To assess the anatomy and position of the 3rd molars the preofferative radiographic examination included a panoramic radiograph, a posteroanterior radiograph with the mouth open and at least 2 intra-oral X-ray films. Additionally, 2 intra-oral periapical radiographs were taken to evaluate the bone level and the prevalence and depth o f intrabony defects on the distal surface of the adjacent 2nd molar (M2). A periodontal probe (Mar-
19
o7
,,
ij
D
During the 1st postoperative week all patients rinsed their mouths with a solution of 0.2% chlorhexidine digluconate twice a day for 1 min each time. After 1 week the patients returned to the department for a check-up and removal of sutures. At this session the patients were instructed to brush their teeth with a gel of 1% chlorhexidine digluconate (Hibitane ® Dental 1%, ICI) twice daily for 3 months. In cases o f alveolitis sicca dolorosa (ASD), i.e. disintegration of the blood clot in the extraction socket yielding offensive odour and severe neuralgic pain, the standardised treatment was thorough saline lavage and application o f a gauze ribbon soaked in Whitehead's varnish. For patients who were to have 2 lower 3rd molars removed, the 2nd operation was performed at the same time as the 3-month re-examination of the oral hygiene status. The preoperative tooth cleaning and all operations were performed by the same surgeon (S.K.), who also removed the sutures and checked up on oral hygiene 1 week and 3 months postoperatively. Statistical methods
Fig. 1. Landmarks used for clinical and radiographic measurements. (A) indicates the free gingival margin, (B) the cemento-enamel junction, (C) the bottom o f the pocket, and (D) the alveolar crest.
The calculation of sample size was based on the assumption that the frequency of intrabony defects _<3 mm is roughly 70% in the population 13. A difference of 25% between the 2 groups was considered sufficient to be
20
Kugelberg et al.
of clinical interest. It was calculated that approximately 80 valid cases were required per group if the level of significance was set at 0.05 and the power at 80%. Each lower 3rd molar removal could be regarded as a single observation13. An analysis of variance, concerning probing depths and intrabony defects, showed that there was no dependence between 2 operations in the same patient. For related samples where measurements were made on an ordinal scale, the sign test was used for statistical analysis. When the data consisted of frequencies in discrete categories, the chi-square test was used to determine the significance of differences between 2 independent samples. The McNemar test for the significance of changes was used for analysing frequency data from 2 related samples, i.e. the changes in the 2 age groups between baseline and 1 year postoperatively. All statistical tests performed were two-tailed and at the 5% significance level, Results
At the preoperative examination, 69 subjects (74.2%) in the group aged _<20 years and 68 (81.9%) of those aged _>30 years were and had always been asymptomatic. In the younger age group, 19 (20.4%) described inconvenience, in terms of tension, pain or swelling during the eruption phase, and 5 (5.4%) mentioned problems with food impaction in the 3rd molar area. The corresponding figures in the older age group were I1 (13.3%) and 4 (4.8%),
respectively. Preoperative treatment of pericoronitis was performed in 1 of the 20-year-olds and in 2 of the 30-yearolds. The operating time for individuals _<20 years of age varied from 3-26 min (mean: 12.8 min). The corresponding range for those > 30 years of age was 5-41 min (mean: 17.3 min). Of the 176 surgical removals of lower 3rd molars, 13 subjects (7.4%) were treated on 2 or 3 further occasions because of alveolitis sicca dolorosa (ASD); 4 of these (4.3%) were _<20 years old and 9 (10.8%) _>30 years old.
Plaque Index, Gingival Index and probing depth
Frequency distributions of preoperative and 1-year postoperative plaque scores, gingival scores and probing depths on the distal surface of the 2nd molar are presented in Table 2. PI. The improved oral hygiene achieved on the day of surgery was maintained during the first 3 months after the operation. At the 3-month examination the percentage of distal tooth surfaces with no or not visible plaque (score 0-1) had increased in both age groups. In the group aged -<20 years 5.1% showed visible plaque (score 2-3), compared with 13.7% in those aged > 30 years. At the re-examination
1 year postoperatively, the distal surfaces of the 2nd molar in both age groups had maintained the improved oral hygiene status achieved on the day of surgery compared with the baseline examination (p<0.001). Thus, 16.1% of the cases _<20 years and 36.1% of the cases > 30 years presented visible plaque on this surface. When comparing the sexes, males > 30 years had significantly more visible plaque 1 year postoperatively than females > 3 0 years (p < 0.001) and males and females in the age group < 20 years. GL At the re-examination 1 year postoperatively, the percentage of bleeding gingival sites (scores 2-3) on the distal surface of the 2nd molar had decreased from 51.6% to 35.5% in the age group _<20 years and from 59.0% to 34.9% in the age group > 30 years. The improvement was statistically significant in the younger as well as the older age group: p<0.05 and p<0.01, respectively. There was no significant difference in gingival condition between males and females in either of the age groups. Probing depth. The distribution of probing depths on the distal surface of the 2nd molar is presented in 2 groups: _<6 and > 7 ram, respectively. At the baseline examination, the probing depth on the distal surface was equal to or exceeded 7 mm in 21.5% of the cases aged <20 years and in 45.8% of the cases aged > 30 years. At the examination 1 year postoperatively, the number of cases with probing depths _>7 mm on the distal surface had significantly decreased in both age groups (p < 0.001). None in the age group _<20 years and only 4.8% of the cases aged _>30 years demonstrated pockets deeper than 7 mm at the re-examination. There was no significant difference in 1-year postoperative probing depth between males and females in either of the age groups. Proximal bone level and intrabony defects
Fig. 2. Periapical radiographs of the 2nd molar region before (1) and 1 year after (2) 3rd molar surgery with (A) and without (B) a periodontal probe as indicator of the intrabony defect. Patient: female, 20 years of age.
Frequency distributions of proximal bone level and intrabony defects on the distal surface of the 2nd molar preoperatively and 1 year postoperatively are presented in Table 3. Proximal bone level. The results of the proximal bone level measurements are presented in 2 groups, comprising the intervals 70-41% and _<40% of the total length of the tooth (Table 3). The interval 70-41% covers examples where
Periodontal healing and third molars
21
sented in 2 groups: _<3 mm and _>4 mm, respectively. In the age group _<20 years, intrabony defects _>4 mm were registered preoperatively in 32.3% and 1 year postoperatively in 14.0% of the PLI/GI 0-1 2-3 0-1 2-3 cases (p < 0.001). The corresponding figPD (mm) <6 >_7 <6 >7 ures in the age group _>30 years were n % n % n % n % 59.0% and 47.0%, respectively (NS). About 70% of those _>4 mm intrabony Preoperative PLI 56 60.2 37 39.8 31 37.3 52 62.7 defects were found among men and GI 45 48.4 48 51.6 34 41.0 49 59.0 30% among women both preoperatively PD 73 78.5 20 21.5 45 54.2 38 45.8 and 1 year postoperatively. The change in number of cases with Postoperative PLI 78 83.9 15 16.1 53 63.9 30 36.1 intrabony defects between the baseline GI 60 64.5 33 35.5 54 65.1 29 34.9 examination and the re-examination 1 PD 93 100.0 79 95.2 4 4.8 year postoperatively is presented in Table 4. In the age group -<20 years, PLI: preop, vs postop. (<20): p<0.001. irrespective of the size of the preoperapreop, vs postop. (>30): p<0.001. <20 vs >30: preop, and postop, p<0.01. tive intrabony defects, 46.2% showed GI: preop, vs postop. (<20): p<0.05). a decrease in depth, 45.2% remained preop, vs postop. (>30): p<0.0l. unchanged and 8.6% increased in depth _<20 vs > 30: preop, and postop. NS. during the follow-up period. The correPD: preop, vs postop. (_<20): p<0.001. sponding figures in the group aged _>30 preop, vs postop. (>30): p<0.001. years were 34.9%, 41.0% and 24.1%, <20 vs >30: preop, p<0.01, postop. NS. respectively. The decrease of cases with intrabony defects > 4 mm was signifishowed a reduction of the alveolar crest cant in the younger age group the height of the alveolar crest was norby 1/2 of the root length or more, com(p<0.001), but not in the older age real or reduced by 1/3 of the root length. group. There was also a difference beIn the interval <40%, the bone level pared with 37.3% of those aged ->30 tween the age groups in the size of the was reduced by 1/2 of the root length years. The height of the alveolar crest on preoperative intrabony defects. In the or more. At the preoperative examithe mesial surface of the 2nd molar did younger group, 90.0% with preoperanationlof the distal surface, 18.3% of not change between the 2 examinations. tive defects _>4 mm showed improvethe'cases < 2 0 years and 41.0% of those _~30 years of age were registered within One year after surgery, all of the mesial ment at the re-examination 1 year postoperatively, while the corresponding figthe ::inferval -<40%. Men had signifi- surfaces in the age group _<20 years showed a normal bone level. In the age ure in the older group was 49.0% cantly lower preoperative bone height group > 30 years, 97.6% showed a nor(p < 0.001). No case was impaired in the than women in both the younger and mal bone level while 2.4% were reduced younger group, while 16.3% of the cases older age groups: p < 0.05 and p < 0.01, with deep preoperative defects in the respectively. At the re-examination 1 by 1/3 of the root length. Intrabony defects. In Table 3, the dis- older group had deteriorated 1 year year postoperatively, significant imafter the 3rd molar removal. provement was only seen in the younger tribution of intrabony defects On the The relationship between the size of age group (p < 0.001), where 2.2% still distal surface of the 2nd molar is prethe intrabony defects and some preoperative, anatomical and pathophysiTable 3. Bone level (BL), shown as 70-41% and _<40% of the total length of the tooth, and ological variables in the 2nd and 3rd intrabony defects (IBD) on the distal surface of the 2nd molar preoperatively and 1 year molar area is presented in Table 5. The postoperatively in relation to age presence of visible plaque and bleeding Age group < 20 years Age group > 30 years and probing were of minor importance in the age group -<20 years. Among BL (%) 70-4l _<40 70-41 _<40 IBD (mm) _<3 >4 <3 >4 the cases _>30 years, 57.7% with high plaque scores showed postoperative inn % n % n % n % trabony defects _>4 ram, compared with Preoperative 29.0% in cases with low scores BL 76 81.7 17 18.3 49 59.0 34 41.0 (19<0.05). In cases with preoperative IBD 63 67.7 30 32.3 34 41.0 49 59.0 ¢ probing depths on the distal surface of Postoperative the 2nd molars > 7 mm, 21.1% of those BL 91 97.8 2 2.2 52 62.7 31 37.3 aged -<20 years and 69.2% aged ->30 IBD 80 86.0 13 14.0 44 53.0 39 47.0 years showed deep intrabony defects 1 BL: preop, vs postop. (<20): p<0.001. year postoperatively. The difference bepreop, vs postop. (>30): NS. tween the number of patients with pre<20 vs >30 preop, p<0.01, postop, p<0.001. operative probing depths of -<6 mm IBD: preop, vs postop. (<20): p<0.001. and those with -> 7 mm who developed preop, vs postop. (>30): NS. deep intrabony defects was statistically <20 vs >30: preop, p<0.001, postop, p<0.001.
Table 2. Plaque Index (PLI), Gingival Index (GI) and probing depth (PD) on the distal surface of the 2nd molar preoperatively and I year postoperatively in the age groups -<20 years and > 30 years, respectively Age group ___20 years Age group _>30 years
22
Kugelberg et al.
Table 4. Change in intrabony defects (IBD) on the distal surface of the 2nd molar between the baseline examination and re-examination t year postoperatively in relation to the size of the preoperative intrabony defect. Improved
Unchanged
n
%
n
%
n
%
Age group _<20 years 0-1 1 2-3 15 >4 27 Total 43
4.8 35.7 90.0 46.2
14 25 3 42
66.7 59.5 10.0 45.2
6 2
28.5 4.8
8
8.6
21 42 30 93
Age group >- 30 years 0-I 2-3 5 >4 24 Total 29
19.2 49.0 34.9
3 14 17 34
37.5 53.9 34.7 41.0
5 7 8 20
62.5 26,9 16,3 24.1
8 26 49 83
IBD (ram)
Deteriorated
Total n
IBD: preop, vs postop. (_<20): p<0.001. preop, vs postop. (>_30): NS. _<20 vs >30 (~1): NS. <20 vs >_30 (2-3): p<0.05. _<20 vs >_30 (_<4): p<0.001.
Table 5. Intrabony defects (IBD) on the distal surface of the 2nd molar in relation to Preoperative Plaque Index distal 2nd molar, Preoperative Gingival Index distal 2nd molar, Preoperative probing depth distal 2nd molar, Preoperative intrabony defect distal 2nd molar, Sagittal inclination 3rd molar, Contact area between 2nd and 3rd molar, Resorption distal root of 2nd molar, Pathological follicle 3rd molar, Smoking habits and Use of oral contraceptives Age group _>30 years
Age group _<20 years IBD (mm)
<3
24
_<3
>_4
n
%
n
%
n
%
n
%
Plaque Index
0 1 2-3
47 33
83.9 89.2
9 4
16.1 10.8 (NS)
22 22
71.0 42.3
9 29.0 30 57.7 (V < 0.05)
Gingival Index
0-1 2-3
38 42
84.4 87.5
7 6
t5.6 12.5 (NS)
17 27
50.0 55.1
17 22
Probing depth
_<6 mm >- 7 mm
65 15
87.8 78.9
9 4
12.2 21.1 (NS)
32 12
72.7 30.8
12 27.3 27 69.2 (p < 0.001)
Preop. IBD
-< 3 mm > 4 mm
62 18
98.4 60.0
1 1.6 12 40.0 (p < 0,001)
31 13
91.2 26.5
3 8.8 36 73.5 (p < 0.001)
Sagittal inclin.
_<50 ° > 50°
52 28
98.1 70,0
1 1.9 12 30.0 (p<0,001)
33 11
71.7 29.7
13 28.3 26 70.3 (p<0.001)
Contact area
small large
61 19
95.3 65.5
3 4.7 l0 34.5 (p < 0.001)
35 9
76.1 24.3
11 23.9 28 75.7 (13< 0.001)
Root resorp,
no yes
79 1
87.8 33.3
1l 2
12.2 66.7 (NS)
43 !
61.4 7.7
27 38.6 12 92.3 (p < 0.0l)
Pathol. follicle
no yes
60 20
85.7 87.0
10 3
14.3 13.0 (NS)
39 5
65.0 21.7
21 35.0 18 78.3 (p < 0.01)
Smoking habits
no yes
57 23
89.1 79.3
7 6
10.9 20.7 (NS)
40 4
60.6 23.5
26 39.4 13 76.5 (p < 0.0 5)
Oral contracept,
no yes
28 14
93.3 87.5
2 2
6.7 12.5 (NS)
28 5
77.8 55.6
8 4
50.0 44.9 (NS)
22.2 44.4 (NS)
significant ( p < 0 . 0 0 1 ) in the older group. Individuals aged _<20 years, with deep preoperative i n t r a b o n y defects, exhibited deep p o s t o p e r a t i v e defects in 4 0 % o f the cases. T h e corres p o n d i n g figure in the g r o u p aged _> 30 years was 73.5%. T h e r e were also statistically significant differences in the n u m b e r with deep i n t r a b o n y defects in b o t h age groups with regard to inclin a t i o n o f the 3rd m o l a r a n d positional relationship between the 2 n d a n d 3rd molars (p < 0.00l). R o o t r e s o r p t i o n o n the distal surface o f the 2 n d m o l a r was more i m p o r t a n t in the older age group, d e m o n s t r a t i n g a prevalence o f 16.9%. Deep p o s t o p e r a t i v e defects, in cases with resorption, were registered in 66.7% a m o n g 20-year-olds (NS) a n d in 92.3% a m o n g 30-year-olds ( p < 0 . 0 1 ) . Pathologically widened follicles were o f m i n o r i m p o r t a n c e in the y o u n g e r age group, while those >_ 30 years w i t h widened follicles exhibited deep i n t r a b o n y defects in 78.3% (p < 0.01). S m o k i n g habits a n d use o f oral contraceptives a n d their relation to p o s t operative i n t r a b o n y defects are also presented in Table 5. Deep p o s t o p e r a t i v e defects a m o n g smokers aged _> 30 years were registered in 76.5%, c o m p a r e d with 39.4% a m o n g n o n - s m o k e r s in the same age g r o u p (p < 0.05). N o significant difference was seen b e t w e e n smokers a n d n o n - s m o k e r s in the age g r o u p _<20 years. N o r was there a n y difference between females using a n d not using oral contraceptives in a n y o f the age groups. Discussion
A l t h o u g h several investigators h a v e s h o w n t h a t i m p a c t e d lower 3rd m o lars ~'2'9'm as well as i m p a c t e d lower 3rd m o l a r surgery 3'7'u'13'~8'21'28m a y result in i n t r a b o n y defects, little i n f o r m a t i o n is available o n the effects o f age o n period o n t a l healing 3'12'~3 or, m o r e precisely, the effects o f the p e r i o d o f time t h a t a n i m p a c t e d lower t h i r d m o l a r is in close proximity to the adjacent second m o l a r root. In a previous retrospective study 13, there was a significant difference between p e r i o d o n t a l healing 2 years after i m p a c f i o n surgery in individuals _<_<25 years c o m p a r e d with individuals > 2 6 years. This difference was even m o r e a p p a r e n t at a r e - e x a m i n a t i o n 4 years postoperatively 12. However, these retrospective studies m a y have resulted in inaccurate estimates o f the true inci-
Periodontal healing and third molars
Fig. 3. Periapical radiographs of the 2nd molar region before (1A) and 1 year after (2A) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect. Patient: male, 20 years of age.
Fig. 4. Periapical radiographs of the 2nd molar region before (1A) and 1 year after (2A) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect. Patient: male, 31 years of age.
Fig. 5. Periapical radiographs of the 2nd molar region before (l) and 1 year after (2) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect on the distal (A) and buccaI (C) surfaces. Patient: male, 31 years of age.
23
dence of postoperative intrabony defects. Thus, the present prospective investigation was undertaken in order to see what impact age and some anatomical and pathophysiological variables had on periodontal healing after impacted lower 3rd molar surgery. The decisive role of careful plaque control in the prevention and treatment of periodontal disease, but also after periodontal regenerative surgery 16,24,29is well documented. When planning a prospective clinical trial to study the importance of a surgical treatment modality on periodontal tissues, a maintenance programme ought to be instituted to achieve an optimal standard of plaque control. The oral hygiene standard and gingival condition improved considerably during the postoperative period in both age groups, and the prevalence of deep periodontal pockets was highly reduced. The oral hygiene programme seemed to have a very strong influence on the postoperative prevalence of deep pockets. The enhanced plaque control during the initial phase of healing in the present study, however, did not seem to affect the prevalence of intrabony defects, as 29.5% of the 176 cases exhibited intrabony defects _>4 mm 1 year postoperatively in the present study, compared with 32.1% in the retrospective study 13. In a multivariate approach by KUGELBERGet al.15, relating periodontal healing after impacted lower 3rd molar surgery to demographic, anatomical, and pathophysiological factors, these regression models explained 45% of the variance in terms of the size of the remaining postoperative intrabony defect and 62% of the variance in terms of periodontal healing after impacted lower 3rd molar surgery. Factors explaining this include: the extent of the intrabony defects preoperatively and the age of the patient at the time of surgery or, more likely, the length of time before surgery (Figs. 3 and 4). Other factors, which were entered into the equation at the 5% significance level, were root resorption of the adjacent second molar and the presence of a pathologically widened follicle (Fig. 5). The presence of alveolitis sicca dolorosa as an explanatory factor was never included in the equation and did not make any contribution to the explanation of postoperative intrabony defects. In the present study, the age of the patient at the time of surgery was found to be of utmost importance as regards the prevalence of postoperative intrabony defects. In the younger age group, pre-
24
Kugelberg et al.
operative presence o f visible plaque, bleeding on probing and probing depths _>7 m m on the distal surface o f the 2nd molar did not seem to affect the healing process. In the older group, however, cases with high plaque scores and deep periodontal pockets demonstrated significantly more deep intrabony defects than cases with no preoperative plaque and deep pockets. R o o t resorption in the contact area between the 2nd and 3rd molar was of importance in both age groups, while a pathologically widened follicle was only important in the older age group. The prevalence of deep intrabony defects preoperatively did not affect the healing of the periodontal tissues among the younger patients as m u c h as it did among the older group. It was also evident that large sagittal inclination o f the third molar and close proximity to the adjacent second m o l a r were more important in jeopardizing the periodontal health on the distal surface in the older age group than in the younger. The use of oral contraceptives a m o n g females did not seem to affect the healing process in any of the age groups. The detrimental effects of smoking on periodontal health has recently been reviewed by PALMER22 and RIVERA-HIDALGO23. In the present study, there was a significant difference between smokers and nonsmokers in the age group > 3 0 years. This finding is in agreement with the findings of other authors 4'5's, who have found that alveolar bone height was significantly reduced in smokers c o m p a r e d with non-smokers. Further, a regression analysis suggested that periodontal breakdown judged from loss of alveolar bone over time was more accelerated in smokers than non-smokers 4. This study has demonstrated that periodontal healing after impacted lower 3rd molar surgery was impaired in individuals over 30 years. Optimization o f the surgical technique and maintenance of enhanced plaque control postoperatively did not compensate for the negative effect emanated from an impacted 3rd molar in long-standing close proximity to the root of the adjacent 2nd molar preoperatively. In conclusion, early removal of impacted lower 3rd molars with large angulation and close positional relationship to the adjacent 2nd molars proved to have a beneficial effect on the periodontal health of the patients. Acknowledgements - The authors would like
to thank Dr. Rolf Karlsson for assistance with the statistical analyses. This study has been
supported by J6nk6ping County Council and the Gothenburg Dental Society.
References I. APP GR, STEPHENSRJ. Periodontal considerations and the impacted tooth. Dent Clin North Am 1979: 23: 359-67. 2. ASHM. Third molars as periodontal problems. Dent Clin North Am 1964: 18: 51-61. 3. ASH M, COSTIGH ER, HAYWARD R. A study of periodontal hazards of third molars. J Periodontol 1962: 33: 20919. 4. BERGSTR(SM J, ELIASSON S. Cigarette smoking and alveolar bone height in subjects with a high standard of oral hygiene. J Clin Periodonto11987: 14: 466-9. 5. BERGSTROMJ, FLODERUS-MYRHEDB. Cotwin control study of the relationship between smoking and some periodontal disease factors. Community Dent Oral Epidemic1. 1983: 11: 113-16. 6. BJ6RNH, HOLMBERGK. Radiographic determination of periodontal bone destruction in epidemiological research. Odontol Rev 1966: 17: 232-50. 7. CHIN QUEETA, GOSSELIND, MILLAREP, STAMMJW. Surgical removal of the fully impacted mandibular third molar. The influence of flap design and alveolar bone height on the periodontal status of the second molar. J Periodontol 1985: 56: 625-30. 8. FELDMANRS, BRAVACOSJS, ROSECL. Association between smoking different tobacco products and periodontal disease indexes. J Periodonto! 1983: 54: 481-7. 9. FIELDING AF, DOUGLASSAF, WHITLEY RD. Reasons for early removal of impacted third molars. Clin Prevent Dentistry 1981: 3: 19-23. 10. GROVESBJ, MOOREJR. The periodontal implications of flap design in lower third molarextractions. Dent Pratt Dent Rec 1970: 20: 297-304. 11. GR(SNDAHLHG, LEKHOLMO. Influence of mandibular third molars on related supporting tissues. Int J Oral Surg 1973: 2: 137-42. 12. KUGELBERGCF. Periodontal healing two and four years after impacted lower third molar surgery. A comparative retrospective study. Int J Oral Maxillofac Surg 1990: 19: 341-45. 13. KUGELBERGCF, AHLSTR(SMU, ERICSONS, HUGOSONA. Periodontal healing after impacted lower third molar surgery. A retrospective study. Int J Oral Surg 1985: 14: 29~40. 14. KUGELBERGCF, AHLSTR~MU, ERICSONS, HUGOSONA. Periodontal healing after impacted lower third molar surgery. Precision and accuracy of radiographic assessment of intrabony defects. Int J Oral Maxillofac Surg 1986: 15: 675-86. 15. KUGELBERGCF, AHLSTROMU, ERICSONS, HUGOSONA, THILANDERH. The influence of anatomical, pathophysiological and
other factors on periodontal healing after impacted lower third molar surgery. A multiple regression analysis. J Clin Periodontol 1991: 18: 37-43. 16. LINImE J, NYMANS. The effect of plaque control and surgical pocket elimination on the establishment and maintenance of periodontal health. A longitudinal study of periodontal therapy in cases of advanced disease. J Clin Periodontol 1975; 2: 67-79. 17. LtE H, SILNESSJ. Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontol Scand 1963: 21: 533-51. 18. MARMARYy, BRAYERL, TZUKERTA, F~LLER L. Alveolar bone repair following extraction of impacted mandibular third molars. Oral Surg 1986: 60: 324-6. 19. MATTSSON O, A magnifying viewer for photofluorographic films. Acta Radiol 1953: 39: 412-14. 20. NORDENRAM/~,GRAVES. Alveolitis sicca dolorosa after removal of impacted mandibular third molars. Int J Oral Surg 1983: 12:226-31. 21. OSBORNEWH, SNYDERAJ, TEMPELTR. Attachment levels and crevicular depth at the distal of mandibular second molars following removal of adjacent third molars. J Periodontol 1982: $3: 93-5. 22. PALMERRM. Tobacco smoking and oral health. Br Dent J 1988: 258-60. 23. RIYERA-HIDALGOF. Smoking and periodontal disease. A review of the literature. J Periodontol 1986: 57: 617-24. 24. ROSLINGB. Plaque control. A determining factor in the treatment of periodontal disease. Thesis. Gothenborg, Sweden, !976. 25. SILNESSJ, LtE H. Periodontal disease in pregnancy. I1 Correlation between oral hygiene and periodontal condition. Acta Odontol Scand 1964: 22: 121-35. 26. STEPHENS RJ, APP GR, FOREMANDW Periodontal evaluation of two mucoperiosteal flaps used in removing impacted mandibular third molars. J Oral Maxillofac Surg 1983: 41: 719-24. 27. SZMYDL. Mucoperiosteal flap. Dent Clin North Am 1971: 15: 299-318. 28. SZMYDL, HESTERWR. Crevicular depth of the second molar in impacted third molar surgery. J Oral Surg 1963: 21: 185-9. 29. WESTFELTE, NYMANS, LINDHEJ, SOCRANSKY S. Use of chlorhexidine as a plaque control measure following surgical treatment of periodontal disease. J Clin Periodontol 1983: 10: 22-36. 30. WOOLFRH, MALQUISTJP, WRIGHTWH. Third molar extractions: periodontal implications of two flap designs. Gen Dent 1978: 26: 52-6. Address: Carl E Kugelberg The Institute for Postgraduate Dental Education Box 1030 S-551 11 Jtnkb'ping Sweden
Carl F, Kugelberg, UIf Ahlstr~m, Sune Ericson, Anders Hugoson, Sven Kvint institute for Postgraduate Dental Education, J6nk6ping, and Department of Oral Surgery, University of Gfteborg, G6teborg, Sweden
A prospectivestudy C. E Kugelberg, U. Ahlstrdm, S. Ericson, A. Hugoson, S. Kvint: Periodontal healing after impacted lower third molar surgery in adolescents and adults. A prospective study. Int. J. Oral Maxillofac. Surg. 1991; 20: 18-24. Abstract. The effects of impacted lower 3rd molar surgery on periodontal tissues in the adjacent 2nd molar area have been investigated in a prospective study comprising 176 cases from 2 age groups: _<20 years (n = 93) and -> 30 years (n = 83), respectively. The preoperative and 1-year postoperative examinations included both clinical and radiographic variables. All patients were subjected to a standardized surgical procedure and optimal plaque control pre-, intra- and postoperatively. Early removal of impacted lower 3rd molars with large angulation and close positional relationship to the adjacent 2nd molar proved to have a beneficial effect on periodontal health.
Third molar removals may result in intrabony defects on the distal surface of the 2nd molar 3,7,11,18,21,28. In a retrospective study KUGELBERGet alJ 3 demonstrated that, 2 years after impacted lower 3rd molar surgery, 32.1% of the cases showed intrabony defects _>4 mm deep on the distal surface of the adjacent 2nd molar. In individuals _<25 years of age almost 50% of the intrabony defects _>4 mm deep at surgery showed periodontal healing 2 years postoperatively, while in only a few per cent of those 26 years or older was healing acceptable. Similar results were achieved by AsH et al. 3 and MARMARY et al. 18. They found that failures in the bone healing process after lower 3rd molar surgery occurred in 3% of individuals aged 20-29 years compared with 21% of those aged 30-50 years. The importance of age was emphasised by KUGELBERG 12 in a further retrospective study, where the long-term effects of impacted lower 3rd molar surgery on periodontal tissues were investigated. At the reexamination 4 years postoperatively, the intrabony defects of nearly 50% of the subjects _<25 years old had improved since the examination 2 years after surgery. In subjects >_26 years
old improvement was only seen in 15% of the cases. Four years after 3rd molar removal, 4.2% of the subjects aged _<25 years showed intrabony defects exceeding 4 mm, compared with 44.4% in the group aged >26 years. It can be inferred from clinical experience that morbidity of the periodontal tissues following impacted lower 3'rd molar surgery may be reduced if they are removed at an early age. In a multiple regression analysis KUGELBERG et al. 15 found that, apart from the extent of preoperative damage to the tissues surrounding the adjacent 2nd molar, the age of the patient at the time of surgery was the most important variable in explaining the variance in postoperative intrabony defects. The aims of this investigation were: 1) to perform a prospective clinical study which compares the periodontal healing after impacted lower 3rd molar surgery under optimal oral hygiene conditions between two different age groups; and 2) to study the importance of some anatomical and pathophysiological variables on the periodontal healing, such as the sagittal inclination of the impacted 3rd molar and its positional relationship to the
Key words: third molar; periodontal healing; intrabony defects. Accepted for publication 3 September 1990
adjacent 2nd molar, the presence of a pathologically widened follicle and resorption of the 2nd molar root.
Material and methods The study comprised 118 patients referred for removal of 176 mandibular 3rd molars (M3). A restricted randomisation was made in order to obtain 2 samples equal in size from 2 age groups: <20 years (n=57) and ->30 years (n=61), respectively. Of a total of 176 3rd molars, 93 molars were from individuals < 20 years and 83 were from individuals ->30 years (Table 1). No significant difference existed in the distribution of males and females in the 2 age groups. The distributions
Table 1. Distribution of the 176 lower 3rd molars according to the age groups and sex of the patients Age group _<20 years Males Females Total Mean (years) SD Range (years)
Age group _>30 years
n
%
n
%
47 46 93
50.5 49.5 100.0
38 45 83
45.8 54.2 100.0
19.3 0.95 16-20
36.7 5.16 30-54
Age groups <20 vs age group _>30 (total): NS.
Periodontal healing and third molars concerning degree of impaction, sagittal inclination and positional relationship to the adjacent 2nd molar were also similar in both age groups. The following inclusion criteria were used: I. Patient willing to participate. 2. Preoperative history proving good general health. 3. Pre- and postoperative examinations, including both clinical and radiographic variables. Clinical examination Prior to 3rd molar removal the patients were examined and a general medical history was taken, including smoking habits, menstrual cycle and use o f oral contraceptives. Anamnestic information concerning previous difficulties or infections in the 3rd molar region was also recorded. The clinical examination was carried out on all 4 tooth surfaces of the 1st and 2nd molars adjacent to the extraction site. Assessments were made regarding the oral hygiene standard, gingival condition and periodontal tissue breakdown in terms of increased probing depths and intrabony defects. Baseline examination comprised the following variables: 1. Plaque Index 25 (PLI). A PLI score of 0-1 corresponded to no or not visible plaque and a PLI score of ~ 3 corresponded to visible plaque. 2. Gingival Index 17 (GI). A GI score of ~ 1 corresponded to healthy gingiva or slight inflammation and a GI score of 2-3 represented moderate changes in texture and colour and/or bleeding on probing. 3. Probing depth (PD). Probing depths were measured with a periodontal probe (Marquis*). Measurements were made to the nearest m m from the free gingival margin to the bottom of the pocket, distance AC in Fig. 1. Only probing depths exceeding 3 mm were recorded. When presenting probing depth measurements, the results have been grouped into pocket depths _>6 mm and _>7 mm. The re-examination took place 1 y e a r a f t e r surgical treatment and included the same clinical and radiographic variables as were used preoperatively.
quis) with the handle cut off served as an indicator. The final positioning of the probe was not assessed until the probe had been moved along the entire distal surface to reach the deepest part. During radiography, the indicator was placed in firm osseous contact. The intra-oral X-ray films were taken first with, and then without, the indicator (Fig.
2). All the measurements on the radiographs were performed at the end of the study. The radiographic material was studied on a horizontal illuminator with diffuse white light, which was masked according to the area of the mounted radiographs. The images were analysed with the aid of observation binoculars according to MATTSSONtg. The following variables were evaluated: 1. Proximal bone level 6 (BL). A transparent plastic ruler with 10 equidistant divisions was placed over the radiograph to estimate the bone level in 10ths of the total length of the tooth. The measurements were recorded in increments of half a division and multiplied by 10. 2. Intrabony defect (IBD). The depth of the intrabony defect was obtained by measuring the distance between the cemento-enamel junction and the bottom of the pocket, as indicated by the probe (distance BD in Fig. 1), with the aid of a transparent plastic ruler graduated in mm. Assessments were also made regarding the sagittal inclination of the 3rd molar, its state
of eruption and contact relationship to the adjacent 2nd molar, pathologically widened follicle M3 and root resorption M2 distal. Preoperative treatment On the operation day, prior to surgery, the 1st and 2nd molars on the extraction site were polished with a rubber cup and an abrasive paste. After the tooth cleaning the patients rinsed their mouths with a solution of 0.2% chlorhexidine digluconate (Hibitane ® Dental 0.2%, ICI). Surgical procedure The 3rd molar removals in women were carried out around the 14th day of the menstrual cycle2°. The patients were treated under aseptic conditions using local anaesthesia (3.6 ml Xylocaine ® adrenaline 20 mg/ml, ASTRA; adrenaline 12.5 #g/ml). A standardised surgical technique was used with a single incision for reflection of an envelope flap as described by SZMYD27. Ostectomy and sectioning were performed with a low-speed rotary instrument under constant irrigation with sterile saline. After removal of the tooth, the extraction socket was carefully cleansed, including removal o f follicular remnants and granulation tissue, and thorough saline lavage. The • time taken for the surgical procedure was measured in minutes from the first incision to the first suture. Postoperative treatment
A
Radiographic examination The radiographic recordings were performed under standardised conditions. Details of the radiographic technique have been previously published t4. To assess the anatomy and position of the 3rd molars the preofferative radiographic examination included a panoramic radiograph, a posteroanterior radiograph with the mouth open and at least 2 intra-oral X-ray films. Additionally, 2 intra-oral periapical radiographs were taken to evaluate the bone level and the prevalence and depth o f intrabony defects on the distal surface of the adjacent 2nd molar (M2). A periodontal probe (Mar-
19
o7
,,
ij
D
During the 1st postoperative week all patients rinsed their mouths with a solution of 0.2% chlorhexidine digluconate twice a day for 1 min each time. After 1 week the patients returned to the department for a check-up and removal of sutures. At this session the patients were instructed to brush their teeth with a gel of 1% chlorhexidine digluconate (Hibitane ® Dental 1%, ICI) twice daily for 3 months. In cases o f alveolitis sicca dolorosa (ASD), i.e. disintegration of the blood clot in the extraction socket yielding offensive odour and severe neuralgic pain, the standardised treatment was thorough saline lavage and application o f a gauze ribbon soaked in Whitehead's varnish. For patients who were to have 2 lower 3rd molars removed, the 2nd operation was performed at the same time as the 3-month re-examination of the oral hygiene status. The preoperative tooth cleaning and all operations were performed by the same surgeon (S.K.), who also removed the sutures and checked up on oral hygiene 1 week and 3 months postoperatively. Statistical methods
Fig. 1. Landmarks used for clinical and radiographic measurements. (A) indicates the free gingival margin, (B) the cemento-enamel junction, (C) the bottom o f the pocket, and (D) the alveolar crest.
The calculation of sample size was based on the assumption that the frequency of intrabony defects _<3 mm is roughly 70% in the population 13. A difference of 25% between the 2 groups was considered sufficient to be
20
Kugelberg et al.
of clinical interest. It was calculated that approximately 80 valid cases were required per group if the level of significance was set at 0.05 and the power at 80%. Each lower 3rd molar removal could be regarded as a single observation13. An analysis of variance, concerning probing depths and intrabony defects, showed that there was no dependence between 2 operations in the same patient. For related samples where measurements were made on an ordinal scale, the sign test was used for statistical analysis. When the data consisted of frequencies in discrete categories, the chi-square test was used to determine the significance of differences between 2 independent samples. The McNemar test for the significance of changes was used for analysing frequency data from 2 related samples, i.e. the changes in the 2 age groups between baseline and 1 year postoperatively. All statistical tests performed were two-tailed and at the 5% significance level, Results
At the preoperative examination, 69 subjects (74.2%) in the group aged _<20 years and 68 (81.9%) of those aged _>30 years were and had always been asymptomatic. In the younger age group, 19 (20.4%) described inconvenience, in terms of tension, pain or swelling during the eruption phase, and 5 (5.4%) mentioned problems with food impaction in the 3rd molar area. The corresponding figures in the older age group were I1 (13.3%) and 4 (4.8%),
respectively. Preoperative treatment of pericoronitis was performed in 1 of the 20-year-olds and in 2 of the 30-yearolds. The operating time for individuals _<20 years of age varied from 3-26 min (mean: 12.8 min). The corresponding range for those > 30 years of age was 5-41 min (mean: 17.3 min). Of the 176 surgical removals of lower 3rd molars, 13 subjects (7.4%) were treated on 2 or 3 further occasions because of alveolitis sicca dolorosa (ASD); 4 of these (4.3%) were _<20 years old and 9 (10.8%) _>30 years old.
Plaque Index, Gingival Index and probing depth
Frequency distributions of preoperative and 1-year postoperative plaque scores, gingival scores and probing depths on the distal surface of the 2nd molar are presented in Table 2. PI. The improved oral hygiene achieved on the day of surgery was maintained during the first 3 months after the operation. At the 3-month examination the percentage of distal tooth surfaces with no or not visible plaque (score 0-1) had increased in both age groups. In the group aged -<20 years 5.1% showed visible plaque (score 2-3), compared with 13.7% in those aged > 30 years. At the re-examination
1 year postoperatively, the distal surfaces of the 2nd molar in both age groups had maintained the improved oral hygiene status achieved on the day of surgery compared with the baseline examination (p<0.001). Thus, 16.1% of the cases _<20 years and 36.1% of the cases > 30 years presented visible plaque on this surface. When comparing the sexes, males > 30 years had significantly more visible plaque 1 year postoperatively than females > 3 0 years (p < 0.001) and males and females in the age group < 20 years. GL At the re-examination 1 year postoperatively, the percentage of bleeding gingival sites (scores 2-3) on the distal surface of the 2nd molar had decreased from 51.6% to 35.5% in the age group _<20 years and from 59.0% to 34.9% in the age group > 30 years. The improvement was statistically significant in the younger as well as the older age group: p<0.05 and p<0.01, respectively. There was no significant difference in gingival condition between males and females in either of the age groups. Probing depth. The distribution of probing depths on the distal surface of the 2nd molar is presented in 2 groups: _<6 and > 7 ram, respectively. At the baseline examination, the probing depth on the distal surface was equal to or exceeded 7 mm in 21.5% of the cases aged <20 years and in 45.8% of the cases aged > 30 years. At the examination 1 year postoperatively, the number of cases with probing depths _>7 mm on the distal surface had significantly decreased in both age groups (p < 0.001). None in the age group _<20 years and only 4.8% of the cases aged _>30 years demonstrated pockets deeper than 7 mm at the re-examination. There was no significant difference in 1-year postoperative probing depth between males and females in either of the age groups. Proximal bone level and intrabony defects
Fig. 2. Periapical radiographs of the 2nd molar region before (1) and 1 year after (2) 3rd molar surgery with (A) and without (B) a periodontal probe as indicator of the intrabony defect. Patient: female, 20 years of age.
Frequency distributions of proximal bone level and intrabony defects on the distal surface of the 2nd molar preoperatively and 1 year postoperatively are presented in Table 3. Proximal bone level. The results of the proximal bone level measurements are presented in 2 groups, comprising the intervals 70-41% and _<40% of the total length of the tooth (Table 3). The interval 70-41% covers examples where
Periodontal healing and third molars
21
sented in 2 groups: _<3 mm and _>4 mm, respectively. In the age group _<20 years, intrabony defects _>4 mm were registered preoperatively in 32.3% and 1 year postoperatively in 14.0% of the PLI/GI 0-1 2-3 0-1 2-3 cases (p < 0.001). The corresponding figPD (mm) <6 >_7 <6 >7 ures in the age group _>30 years were n % n % n % n % 59.0% and 47.0%, respectively (NS). About 70% of those _>4 mm intrabony Preoperative PLI 56 60.2 37 39.8 31 37.3 52 62.7 defects were found among men and GI 45 48.4 48 51.6 34 41.0 49 59.0 30% among women both preoperatively PD 73 78.5 20 21.5 45 54.2 38 45.8 and 1 year postoperatively. The change in number of cases with Postoperative PLI 78 83.9 15 16.1 53 63.9 30 36.1 intrabony defects between the baseline GI 60 64.5 33 35.5 54 65.1 29 34.9 examination and the re-examination 1 PD 93 100.0 79 95.2 4 4.8 year postoperatively is presented in Table 4. In the age group -<20 years, PLI: preop, vs postop. (<20): p<0.001. irrespective of the size of the preoperapreop, vs postop. (>30): p<0.001. <20 vs >30: preop, and postop, p<0.01. tive intrabony defects, 46.2% showed GI: preop, vs postop. (<20): p<0.05). a decrease in depth, 45.2% remained preop, vs postop. (>30): p<0.0l. unchanged and 8.6% increased in depth _<20 vs > 30: preop, and postop. NS. during the follow-up period. The correPD: preop, vs postop. (_<20): p<0.001. sponding figures in the group aged _>30 preop, vs postop. (>30): p<0.001. years were 34.9%, 41.0% and 24.1%, <20 vs >30: preop, p<0.01, postop. NS. respectively. The decrease of cases with intrabony defects > 4 mm was signifishowed a reduction of the alveolar crest cant in the younger age group the height of the alveolar crest was norby 1/2 of the root length or more, com(p<0.001), but not in the older age real or reduced by 1/3 of the root length. group. There was also a difference beIn the interval <40%, the bone level pared with 37.3% of those aged ->30 tween the age groups in the size of the was reduced by 1/2 of the root length years. The height of the alveolar crest on preoperative intrabony defects. In the or more. At the preoperative examithe mesial surface of the 2nd molar did younger group, 90.0% with preoperanationlof the distal surface, 18.3% of not change between the 2 examinations. tive defects _>4 mm showed improvethe'cases < 2 0 years and 41.0% of those _~30 years of age were registered within One year after surgery, all of the mesial ment at the re-examination 1 year postoperatively, while the corresponding figthe ::inferval -<40%. Men had signifi- surfaces in the age group _<20 years showed a normal bone level. In the age ure in the older group was 49.0% cantly lower preoperative bone height group > 30 years, 97.6% showed a nor(p < 0.001). No case was impaired in the than women in both the younger and mal bone level while 2.4% were reduced younger group, while 16.3% of the cases older age groups: p < 0.05 and p < 0.01, with deep preoperative defects in the respectively. At the re-examination 1 by 1/3 of the root length. Intrabony defects. In Table 3, the dis- older group had deteriorated 1 year year postoperatively, significant imafter the 3rd molar removal. provement was only seen in the younger tribution of intrabony defects On the The relationship between the size of age group (p < 0.001), where 2.2% still distal surface of the 2nd molar is prethe intrabony defects and some preoperative, anatomical and pathophysiTable 3. Bone level (BL), shown as 70-41% and _<40% of the total length of the tooth, and ological variables in the 2nd and 3rd intrabony defects (IBD) on the distal surface of the 2nd molar preoperatively and 1 year molar area is presented in Table 5. The postoperatively in relation to age presence of visible plaque and bleeding Age group < 20 years Age group > 30 years and probing were of minor importance in the age group -<20 years. Among BL (%) 70-4l _<40 70-41 _<40 IBD (mm) _<3 >4 <3 >4 the cases _>30 years, 57.7% with high plaque scores showed postoperative inn % n % n % n % trabony defects _>4 ram, compared with Preoperative 29.0% in cases with low scores BL 76 81.7 17 18.3 49 59.0 34 41.0 (19<0.05). In cases with preoperative IBD 63 67.7 30 32.3 34 41.0 49 59.0 ¢ probing depths on the distal surface of Postoperative the 2nd molars > 7 mm, 21.1% of those BL 91 97.8 2 2.2 52 62.7 31 37.3 aged -<20 years and 69.2% aged ->30 IBD 80 86.0 13 14.0 44 53.0 39 47.0 years showed deep intrabony defects 1 BL: preop, vs postop. (<20): p<0.001. year postoperatively. The difference bepreop, vs postop. (>30): NS. tween the number of patients with pre<20 vs >30 preop, p<0.01, postop, p<0.001. operative probing depths of -<6 mm IBD: preop, vs postop. (<20): p<0.001. and those with -> 7 mm who developed preop, vs postop. (>30): NS. deep intrabony defects was statistically <20 vs >30: preop, p<0.001, postop, p<0.001.
Table 2. Plaque Index (PLI), Gingival Index (GI) and probing depth (PD) on the distal surface of the 2nd molar preoperatively and I year postoperatively in the age groups -<20 years and > 30 years, respectively Age group ___20 years Age group _>30 years
22
Kugelberg et al.
Table 4. Change in intrabony defects (IBD) on the distal surface of the 2nd molar between the baseline examination and re-examination t year postoperatively in relation to the size of the preoperative intrabony defect. Improved
Unchanged
n
%
n
%
n
%
Age group _<20 years 0-1 1 2-3 15 >4 27 Total 43
4.8 35.7 90.0 46.2
14 25 3 42
66.7 59.5 10.0 45.2
6 2
28.5 4.8
8
8.6
21 42 30 93
Age group >- 30 years 0-I 2-3 5 >4 24 Total 29
19.2 49.0 34.9
3 14 17 34
37.5 53.9 34.7 41.0
5 7 8 20
62.5 26,9 16,3 24.1
8 26 49 83
IBD (ram)
Deteriorated
Total n
IBD: preop, vs postop. (_<20): p<0.001. preop, vs postop. (>_30): NS. _<20 vs >30 (~1): NS. <20 vs >_30 (2-3): p<0.05. _<20 vs >_30 (_<4): p<0.001.
Table 5. Intrabony defects (IBD) on the distal surface of the 2nd molar in relation to Preoperative Plaque Index distal 2nd molar, Preoperative Gingival Index distal 2nd molar, Preoperative probing depth distal 2nd molar, Preoperative intrabony defect distal 2nd molar, Sagittal inclination 3rd molar, Contact area between 2nd and 3rd molar, Resorption distal root of 2nd molar, Pathological follicle 3rd molar, Smoking habits and Use of oral contraceptives Age group _>30 years
Age group _<20 years IBD (mm)
<3
24
_<3
>_4
n
%
n
%
n
%
n
%
Plaque Index
0 1 2-3
47 33
83.9 89.2
9 4
16.1 10.8 (NS)
22 22
71.0 42.3
9 29.0 30 57.7 (V < 0.05)
Gingival Index
0-1 2-3
38 42
84.4 87.5
7 6
t5.6 12.5 (NS)
17 27
50.0 55.1
17 22
Probing depth
_<6 mm >- 7 mm
65 15
87.8 78.9
9 4
12.2 21.1 (NS)
32 12
72.7 30.8
12 27.3 27 69.2 (p < 0.001)
Preop. IBD
-< 3 mm > 4 mm
62 18
98.4 60.0
1 1.6 12 40.0 (p < 0,001)
31 13
91.2 26.5
3 8.8 36 73.5 (p < 0.001)
Sagittal inclin.
_<50 ° > 50°
52 28
98.1 70,0
1 1.9 12 30.0 (p<0,001)
33 11
71.7 29.7
13 28.3 26 70.3 (p<0.001)
Contact area
small large
61 19
95.3 65.5
3 4.7 l0 34.5 (p < 0.001)
35 9
76.1 24.3
11 23.9 28 75.7 (13< 0.001)
Root resorp,
no yes
79 1
87.8 33.3
1l 2
12.2 66.7 (NS)
43 !
61.4 7.7
27 38.6 12 92.3 (p < 0.0l)
Pathol. follicle
no yes
60 20
85.7 87.0
10 3
14.3 13.0 (NS)
39 5
65.0 21.7
21 35.0 18 78.3 (p < 0.01)
Smoking habits
no yes
57 23
89.1 79.3
7 6
10.9 20.7 (NS)
40 4
60.6 23.5
26 39.4 13 76.5 (p < 0.0 5)
Oral contracept,
no yes
28 14
93.3 87.5
2 2
6.7 12.5 (NS)
28 5
77.8 55.6
8 4
50.0 44.9 (NS)
22.2 44.4 (NS)
significant ( p < 0 . 0 0 1 ) in the older group. Individuals aged _<20 years, with deep preoperative i n t r a b o n y defects, exhibited deep p o s t o p e r a t i v e defects in 4 0 % o f the cases. T h e corres p o n d i n g figure in the g r o u p aged _> 30 years was 73.5%. T h e r e were also statistically significant differences in the n u m b e r with deep i n t r a b o n y defects in b o t h age groups with regard to inclin a t i o n o f the 3rd m o l a r a n d positional relationship between the 2 n d a n d 3rd molars (p < 0.00l). R o o t r e s o r p t i o n o n the distal surface o f the 2 n d m o l a r was more i m p o r t a n t in the older age group, d e m o n s t r a t i n g a prevalence o f 16.9%. Deep p o s t o p e r a t i v e defects, in cases with resorption, were registered in 66.7% a m o n g 20-year-olds (NS) a n d in 92.3% a m o n g 30-year-olds ( p < 0 . 0 1 ) . Pathologically widened follicles were o f m i n o r i m p o r t a n c e in the y o u n g e r age group, while those >_ 30 years w i t h widened follicles exhibited deep i n t r a b o n y defects in 78.3% (p < 0.01). S m o k i n g habits a n d use o f oral contraceptives a n d their relation to p o s t operative i n t r a b o n y defects are also presented in Table 5. Deep p o s t o p e r a t i v e defects a m o n g smokers aged _> 30 years were registered in 76.5%, c o m p a r e d with 39.4% a m o n g n o n - s m o k e r s in the same age g r o u p (p < 0.05). N o significant difference was seen b e t w e e n smokers a n d n o n - s m o k e r s in the age g r o u p _<20 years. N o r was there a n y difference between females using a n d not using oral contraceptives in a n y o f the age groups. Discussion
A l t h o u g h several investigators h a v e s h o w n t h a t i m p a c t e d lower 3rd m o lars ~'2'9'm as well as i m p a c t e d lower 3rd m o l a r surgery 3'7'u'13'~8'21'28m a y result in i n t r a b o n y defects, little i n f o r m a t i o n is available o n the effects o f age o n period o n t a l healing 3'12'~3 or, m o r e precisely, the effects o f the p e r i o d o f time t h a t a n i m p a c t e d lower t h i r d m o l a r is in close proximity to the adjacent second m o l a r root. In a previous retrospective study 13, there was a significant difference between p e r i o d o n t a l healing 2 years after i m p a c f i o n surgery in individuals _<_<25 years c o m p a r e d with individuals > 2 6 years. This difference was even m o r e a p p a r e n t at a r e - e x a m i n a t i o n 4 years postoperatively 12. However, these retrospective studies m a y have resulted in inaccurate estimates o f the true inci-
Periodontal healing and third molars
Fig. 3. Periapical radiographs of the 2nd molar region before (1A) and 1 year after (2A) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect. Patient: male, 20 years of age.
Fig. 4. Periapical radiographs of the 2nd molar region before (1A) and 1 year after (2A) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect. Patient: male, 31 years of age.
Fig. 5. Periapical radiographs of the 2nd molar region before (l) and 1 year after (2) 3rd molar surgery. A periodontal probe was used as indicator of the intrabony defect on the distal (A) and buccaI (C) surfaces. Patient: male, 31 years of age.
23
dence of postoperative intrabony defects. Thus, the present prospective investigation was undertaken in order to see what impact age and some anatomical and pathophysiological variables had on periodontal healing after impacted lower 3rd molar surgery. The decisive role of careful plaque control in the prevention and treatment of periodontal disease, but also after periodontal regenerative surgery 16,24,29is well documented. When planning a prospective clinical trial to study the importance of a surgical treatment modality on periodontal tissues, a maintenance programme ought to be instituted to achieve an optimal standard of plaque control. The oral hygiene standard and gingival condition improved considerably during the postoperative period in both age groups, and the prevalence of deep periodontal pockets was highly reduced. The oral hygiene programme seemed to have a very strong influence on the postoperative prevalence of deep pockets. The enhanced plaque control during the initial phase of healing in the present study, however, did not seem to affect the prevalence of intrabony defects, as 29.5% of the 176 cases exhibited intrabony defects _>4 mm 1 year postoperatively in the present study, compared with 32.1% in the retrospective study 13. In a multivariate approach by KUGELBERGet al.15, relating periodontal healing after impacted lower 3rd molar surgery to demographic, anatomical, and pathophysiological factors, these regression models explained 45% of the variance in terms of the size of the remaining postoperative intrabony defect and 62% of the variance in terms of periodontal healing after impacted lower 3rd molar surgery. Factors explaining this include: the extent of the intrabony defects preoperatively and the age of the patient at the time of surgery or, more likely, the length of time before surgery (Figs. 3 and 4). Other factors, which were entered into the equation at the 5% significance level, were root resorption of the adjacent second molar and the presence of a pathologically widened follicle (Fig. 5). The presence of alveolitis sicca dolorosa as an explanatory factor was never included in the equation and did not make any contribution to the explanation of postoperative intrabony defects. In the present study, the age of the patient at the time of surgery was found to be of utmost importance as regards the prevalence of postoperative intrabony defects. In the younger age group, pre-
24
Kugelberg et al.
operative presence o f visible plaque, bleeding on probing and probing depths _>7 m m on the distal surface o f the 2nd molar did not seem to affect the healing process. In the older group, however, cases with high plaque scores and deep periodontal pockets demonstrated significantly more deep intrabony defects than cases with no preoperative plaque and deep pockets. R o o t resorption in the contact area between the 2nd and 3rd molar was of importance in both age groups, while a pathologically widened follicle was only important in the older age group. The prevalence of deep intrabony defects preoperatively did not affect the healing of the periodontal tissues among the younger patients as m u c h as it did among the older group. It was also evident that large sagittal inclination o f the third molar and close proximity to the adjacent second m o l a r were more important in jeopardizing the periodontal health on the distal surface in the older age group than in the younger. The use of oral contraceptives a m o n g females did not seem to affect the healing process in any of the age groups. The detrimental effects of smoking on periodontal health has recently been reviewed by PALMER22 and RIVERA-HIDALGO23. In the present study, there was a significant difference between smokers and nonsmokers in the age group > 3 0 years. This finding is in agreement with the findings of other authors 4'5's, who have found that alveolar bone height was significantly reduced in smokers c o m p a r e d with non-smokers. Further, a regression analysis suggested that periodontal breakdown judged from loss of alveolar bone over time was more accelerated in smokers than non-smokers 4. This study has demonstrated that periodontal healing after impacted lower 3rd molar surgery was impaired in individuals over 30 years. Optimization o f the surgical technique and maintenance of enhanced plaque control postoperatively did not compensate for the negative effect emanated from an impacted 3rd molar in long-standing close proximity to the root of the adjacent 2nd molar preoperatively. In conclusion, early removal of impacted lower 3rd molars with large angulation and close positional relationship to the adjacent 2nd molars proved to have a beneficial effect on the periodontal health of the patients. Acknowledgements - The authors would like
to thank Dr. Rolf Karlsson for assistance with the statistical analyses. This study has been
supported by J6nk6ping County Council and the Gothenburg Dental Society.
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other factors on periodontal healing after impacted lower third molar surgery. A multiple regression analysis. J Clin Periodontol 1991: 18: 37-43. 16. LINImE J, NYMANS. The effect of plaque control and surgical pocket elimination on the establishment and maintenance of periodontal health. A longitudinal study of periodontal therapy in cases of advanced disease. J Clin Periodontol 1975; 2: 67-79. 17. LtE H, SILNESSJ. Periodontal disease in pregnancy. I. Prevalence and severity. Acta Odontol Scand 1963: 21: 533-51. 18. MARMARYy, BRAYERL, TZUKERTA, F~LLER L. Alveolar bone repair following extraction of impacted mandibular third molars. Oral Surg 1986: 60: 324-6. 19. MATTSSON O, A magnifying viewer for photofluorographic films. Acta Radiol 1953: 39: 412-14. 20. NORDENRAM/~,GRAVES. Alveolitis sicca dolorosa after removal of impacted mandibular third molars. Int J Oral Surg 1983: 12:226-31. 21. OSBORNEWH, SNYDERAJ, TEMPELTR. Attachment levels and crevicular depth at the distal of mandibular second molars following removal of adjacent third molars. J Periodontol 1982: $3: 93-5. 22. PALMERRM. Tobacco smoking and oral health. Br Dent J 1988: 258-60. 23. RIYERA-HIDALGOF. Smoking and periodontal disease. A review of the literature. J Periodontol 1986: 57: 617-24. 24. ROSLINGB. Plaque control. A determining factor in the treatment of periodontal disease. Thesis. Gothenborg, Sweden, !976. 25. SILNESSJ, LtE H. Periodontal disease in pregnancy. I1 Correlation between oral hygiene and periodontal condition. Acta Odontol Scand 1964: 22: 121-35. 26. STEPHENS RJ, APP GR, FOREMANDW Periodontal evaluation of two mucoperiosteal flaps used in removing impacted mandibular third molars. J Oral Maxillofac Surg 1983: 41: 719-24. 27. SZMYDL. Mucoperiosteal flap. Dent Clin North Am 1971: 15: 299-318. 28. SZMYDL, HESTERWR. Crevicular depth of the second molar in impacted third molar surgery. J Oral Surg 1963: 21: 185-9. 29. WESTFELTE, NYMANS, LINDHEJ, SOCRANSKY S. Use of chlorhexidine as a plaque control measure following surgical treatment of periodontal disease. J Clin Periodontol 1983: 10: 22-36. 30. WOOLFRH, MALQUISTJP, WRIGHTWH. Third molar extractions: periodontal implications of two flap designs. Gen Dent 1978: 26: 52-6. Address: Carl E Kugelberg The Institute for Postgraduate Dental Education Box 1030 S-551 11 Jtnkb'ping Sweden