Trauma; preprostheticsurgery

Periodontal.healing two and four years after mpacted lower third molar surgery

Carl F. Kugelberg Institute for Postgraduate Dental Education, Jfnk6ping, and Department of Oral Surgery, University of G6teborg, Sweden

A comparativeretrospectivestudy C. E Kugelberg: Periodontal healing two and four years after impacted lower third molar surgery. Int. J. Oral Maxillofac. Surg. 1990; 19: 341-345. Abstract. The long-term effects on periodontal tissues of impacted lower 3rd molar surgery have been investigated in a retrospective study comprising 51 cases. The postoperative examinations took place 2 and 4 years after the surgical treatment and included both clinical and radiographic variables. Assessments were made regarding the oral hygiene status, gingival condition and periodontal tissue breakdown in terms of increased probing depths and intrabony defects. Comparing the results of the two examinations, no significant changes of the incidence of plaque and gingivitis were seen on the distal surface of the 2nd molar, nor any significant change concerning the probing depth. The proximal bone level distal to the second molar was recorded by radiographic examination with a cut-off periodontal probe as indicator. Two years postoperatively, 16.7% of the cases aged _26 years. At the 4-year re-examination, the corresponding figures were 4.2% and 44.4%, respectively. The improvement concerning the alveolar bone level was mainly seen in individuals under 25 years. Some factors affecting the periodontal healing after impacted lower 3rd molar surgery are discussed.

In a retrospective study by KUGELBERG et al. 11, it was shown that 2 years after impacted lower 3rd molar surgery in 215 cases, 43.3% of the patients exhibited probing depths exceeding 7 mm and 32.1% intrabony defects exceeding 4 mm on the distal surface of the adjacent second molar. It was also shown that when comparing the pre- and postoperative measurements of intrabony defects, there was an almost 50% reduction in the number of deep defects in individuals up to 25 years, while only a few per cent of those over 25 years demonstrated acceptable periodontal healing. Previous studies concerning the effect of surgical removal of impacted 3rd molars on the periodontal health of the adjacent 2nd molar have mainly used follow-up periods of up to 12 months 8'19'23'25. Only ASH et al? mentioned in their study that of the original 225 cases, 86 were followed for 2 years and 38 for 3 years after 3rd molar removals, but these cases did not indicate

any significant change in the pattern of results obtained after 1 year. Thus, there is still insufficient information about the long-term effects of 3rd molar removals on periodontal tissues of adjacent 2nd molars, and what impact the age of the patient at the time of surgery has on periodontal healing. We do not know whether periodontal healing in the 3rd molar area is terminated after 1 or 2 years. The periodontal repair or regeneration may be a continuing process over a longer period. The aim of the present study was to compare the periodontal condition of the adjacent 2nd molar 2 and 4 years after impacted lower 3rd molar surgery with special emphasis on age.

Material and methods The study comprised 51 subjects examined 2 and 4 years after impacted lower 3rd molar surgery, which was performed at the Department of Oral Surgery of the Institute for Postgraduate Dental Education, J6nk6ping. The

Key words: third molar; periodontal healing; intrabony defects. Accepted for publication 2t June 1990

51 subjects (23 males and 28 females; age range 17 to 53 years) were selected at random from 215 participants in a retrospective survey by KUGELBBgGet al.11, which evaluated the periodontal health of the adjacent 2nd molar 2 years after surgery. The sample is presented in Table 1. The distribution concerning degree of impaction, angulation and positional relationship to the adjacent 2nd molar was similar in both sexes. Details of the surgical procedure and the immediate postoperative care were presented in a previous study11. At the examination 2 years after the 3rd molar removals, the patients were informed of the condition of the distal surface of the 2nd molar adjacent to the extraction site. Instructions in oral hygiene measures were given when indicated. During the interval between the recalls 2 and 4 years, postoperatively, no further active treatment was performed to improve the condition of the distal surface. The re-examination took place 4 years after the lower 3rd molar surgery, and 2 years after the previous postoperative examination H. It included the same clinicaland radiographic variables as used earlier. The clinical examination was performed on the 1st and 2nd molars adjacent to the

342

Kugelberg

Table 1. Distribution of the 51 3rd molars according to the age of the patients Age group (years)

Selected sample n %

35

11 13 10 10 7

21.6 25.5 19.6 19.6 13.7

Total

51

100.0

Mean (years) SD

27.3 7.24

extraction site. Assessments were made regarding oral hygiene status, gingival condition and periodontal tissue breakdown, and comprised the following variables: 1. Plaque Index (PLI22). A PLI score of 0.1 corresponded to no or not visible plaque and a PLI score of 2-3 corresponded to visible plaque. 2. Gingival Index (GI15). A GI score of 0-1 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 mm from the free gingival margin to the bottom of the pocket. Only probing depths exceeding 3 mm were recorded. When presenting probing depth measurements, the results were grouped into pocket depths _7 ram. The radiographic recordings were performed under standardised conditions using a Philips Oralix ® 65 and long-cone technique plus Kodak UltraSpeed ® periapicat films 12. Two intra-oral periapical radiographs were taken to evaluate the alveolar bone level and the prevalence and depth of intrabony defects on the distal surface of the adjacent 2nd molar on the extraction site (Fig. I). A periodontal probe (Marquis) with the handle cut

off served as an indicator. The final positioning of the probe was not assessed until it 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. All measurements on the radiographs were performed by the examiner at the end of the study. The images were analysed with the aid of observation binoculars according to MATTSSON 18. Details of the precision and accuracy of the radiographic assessment of intrabony defects on the distal surface of the lower second molar have been presented in a methodological study ~2. The following variables were evaluated: 1. Proximal bone level (BL4). A transparent plastic ruler with 10 equidistant divisions was placed over the radiograph to estimate the bone level in tenths of the total length of the tooth. The measurements were recorded in increments of half a division and multiplied by 10. 2. lntrabony defect (IBD). The depth of the intrabony defects was obtained by measuring the distance between the cemento-enamel junction and the bottom of the pocket, as indicated by the probe, with the aid of a transparent plastic ruler graduated in mm.

Statistical methods

Each lower 3rd molar removal could be regarded as an independent observation H. 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 chisquare 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 fre-

quency data from 2 related samples, i.e. the changes in the 2 age-groups between 2 and 4 years postoperatively. All statistical tests performed were two-tailed and at the 5% significance level.

Results

The results are presented in Tables 2-4. The m a t e r i a l has b e e n divided into 2 age groups, < 2 5 years a n d > 26 years to c o m p a r e the y o u n g e r a n d older patients. Frequency distributions o f p l a q u e scores, gingival scores a n d p r o b i n g d e p t h s o n the distal surface o f the 2 n d m o l a r 2 a n d 4 years postoperatively are presented in Table 2. T h e r e were n o statistically significant changes in a n y o f the 3 clinical variables between the 2 examinations. B o t h age g r o u p s s h o w e d virtually the same recordings 2 a n d 4 years postoperatively. A t the 4-year re-examination, 2 5 . 0 % o f the cases < 2 5 years o f age still c h i n t e d a p r o b i n g d e p t h o f 7 m m or m o r e o n the distal surface o f the 2 n d m o l a r adjacent to the extraction site. D e e p e n e d pockets occurred twice as often (51.9%) in individuals > 26 years. T h e results o f the p r o x i m a l b o n e level m e a s u r e m e n t s are d i c h o t o m i s e d in Table 3. The 2 groups comprise the intervals 7 0 - 4 1 % a n d < 4 0 % o f the t o t a l length o f the t o o t h . T h e interval 7 0 - 4 1 % covers examples where the height o f the alveolar crest was n o r m a l or reduced b y 1/3 o f the r o o t length. In the interval < 4 0 % , the b o n e level was reduced by 1/2 o f the root length or more. There was n o statistically significant alteration in the height o f the alveolar crest o n the distal surface o f the 2nd m o l a r between the 2- a n d 4-year

Fig. 1. Periapical radiographs of the 2nd molar 2 years (1) and 4 years (2) after 3rd molar surgery with (A) and without (B) a periodontal probe as indicator of the intrabony defect. Patient: male, 26 years of age.

Periodontal healing and third molars Table 2. Plaque Index (PLI), Gingival Index (GI) and probing depth (PD) on the distal surface of the 2nd molar 2 and 4 years postoperatively in relation to age. (26 years: n = 27). 2 years PLI/GI PD (ram)

4 years

0-1 7

0-1 7

%

n

%

n

%

n

%

Age group _ 26 (years) PLI 22 GI 20 PD 12

81.5 74.1 44.4

5 7 15

18.5 25.9 55.6

23 22 13

85.2 81.5 48.1

4 5 14

14.8 18.5 51.9

2 vs 4 years (_26): PLI, GI _26 (2 years): PLI, < 25 vs > 26 (4 years): PLI,

and PD NS. and PD NS. GI and PD NS. GI and PD NS.

examinations for either age group. Nor was there any change in the height of the alveolar crest on the mesial surface of the 2nd molar between the 2 registrations. Most of the mesial surfaces showed normal bone levels, and none was reduced by more than 1/3 of the root length. However, there was a statistically significant difference between the 2 age groups regarding the height of the alveolar crest on the distal surface of the 2nd molar at both examinations

(p < 0.05). Intra-individual changes in proximal bone levels between the examinations showed significant improvement in individuals 26 years, 22.2% of the cases showed a reduction of the alveolar crest on the distal surface of

the 2nd molar by 1/2 of the root length or more at the 4-year examination. Recordings of intrabony defects are presented in Table 3. The data are grouped into 2 classes according to the depth of the intrabony defects: < 3 and _>4 mm. A bone loss of < 3 mm was considered as an acceptable postoperative IBD. There was no statistically significant difference in the distribution of subjects between the classes at the 2and 4-year examinations, in either of the age groups. There was, however, a significant improvement in the intra-individual intrabony defects between the examinations in subjects _

Periodontal healing two and four years after impacted lower third molar surgery. A comparative retrospective study.

The long-term effects on periodontal tissues of impacted lower 3rd molar surgery have been investigated in a retrospective study comprising 51 cases. ...
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