Spontaneous bone regeneration after surgical extraction of a horizontally impacted mandibular third molar: a retrospective panoramic radiograph analysis / 대한악안면성형재건외과학회지

BACKGROUND: The mandibular third molar (M3) is typically the last permanent tooth to erupt because of insufficient space and thick soft tissues covering its surface. Problems such as alveolar bone loss, development of a periodontal pocket, exposure of cementum, gingival recession, and dental caries can be found in the adjacent second molars (M2) following M3 extraction. The specific aims of the study were to assess the amount and rate of bone regeneration on the distal surface of M2 and to evaluate the aspects of bone regeneration in terms of varying degree of impaction. METHODS: Four series of panoramic radiographic images were obtained from the selected cases, including images from the first visit, immediately after extraction, 6 weeks, and 6 months after extraction. ImageJ software® (NIH, USA) was used to measure linear distance from the region of interest to the distal root of the adjacent M2. Radiographic infrabony defect (RID) values were calculated from the measured radiographic bone height and cementoenamel junction with distortion compensation. Repeated measures of analysis of variance and one-way analysis of variance were conducted to analyze the statistical significant difference between RID and time, and a Spearman correlation test was conducted to assess the relationship between Pederson’s difficulty index (DI) and RID. RESULTS: A large RID (> 6 mm) can be reduced gradually and consistently over time. More than half of the samples recovered nearly to their normal healthy condition (RID ≤ 3 mm) by the 6-month follow-up. DI affected the first 6 weeks of post-extraction period and only showed a significant positive correlation with respect to the difference between baseline and final RID. CONCLUSIONS: Additional treatments on M2 for a minimum of 6 months after an M3 extraction could be recommended. Although DI may affect bone regeneration during the early healing period, further study is required to elucidate any possible factors associated with the healing process. The DI does not cause any long-term adverse effects on bone regeneration after surgical extraction.

Prevalence And Distribution of Vertical Osseous Defects In Patients Being Treated For Chronic Periodontitis.

Background: The aim of the study was to determine the prevalence and distribution of vertical osseous defects in patients who underwent open flap debridement. Methods: A total of 83 subjects were examined for prevalence of vertical defects using direct observation during periodontal surgery. All patients required periodontal surgery in one or more segments. The diagnosis of periodontitis was made after clinical and radiographic examination. Periodontal surgery was performed on each patient and full thickness mucoperiosteal flaps were elevated to gain access to root and osseous structures. The vertical osseous defects were explored surgically using mouth mirror, explorer and a periodontal probe. Results: A total of 141 vertical osseous defects were detected in the 677 teeth assessed during surgical exposure. Of these 81 vertical defects were found in the maxilla and 60 vertical defects were found in the mandible. Craters accounted for almost 44% of the total defects. The posterior maxilla had the highest percentage of teeth with vertical defects (26.23%) while the mandibular anterior segment had the lowest percentage of vertical defects. Conclusion: The posterior maxilla had the highest percentage of vertical osseous defects which can be explained by the fact that greater thickness of supporting bone allows formation of a greater number of infrabony defects. Craters were found to be the most common defect.

Radiographic evaluation of infra-bony defects treated by bone graft procedures / 대한치주과학회지

PURPOSE: A number of techniques and materials have been used for periodontal regeneration and bone graft procedures with guided tissue regeneration(GTR) have been suggested as alternatives to osseous surgery in the management of local infra-bony defects. However, the long-term stability and treatment outcome following bone graft procedure of infra-bony defects is poorly documented. The purpose of this study was to assess radiographic change in infra-bony defects over 2 years after bone graft procedures with various graft materials. MATERIAL AND METHODS: Patients attending the department of periodontics of Kyungpook National University Hospital were studied. Patients showed clinical and radiographic evidence of infra-bony defect(s). 44 sites of 34 patients aged 31 to 69 (mean age 48.3) were treated by bone graft procedure with a bone graft material. Baseline and 2-year follow-up radiographs were collected and evaluated for this study. Radiographic assessment includes a bone fill, bone crest change, defect resolution, and % of defect resolution. Pre- and post-treatment differences between variables (maxilla and mandible, defect depth, defect angle, bone graft materials) using the paired t-test were examined. RESULT: We observed 1.15+/-1.95 mm of bone fill, 0.40+/-1.19 mm of crestal resorption, 1.55+/-1.77 mm of defect resolution, and 40+/-44% of percentage of defect resolution. Deeper initial defect depth, narrower initial defect angle showed significantly greater bone fill, defect resolution, and % of defect resolution. But no significant difference was observed in graft sites and graft materials. CONCLUSION: If good oral hygiene maintenance and periodic recall check of patients is assured, bone graft procedure using various graft materials is one of the appropriate treatment modality for regenerative therapy of infra-bony defects.

Clinical comparison of resorbable and nonresorbable Barrier in guided tissue regeneration of human intrabony defects / 대한치주과학회지

The purpose of this study was to compare the clinical results of guided tissue regeneration(GTR) using a resorbable barrier manufactured from an copolymer of polylactic acid (PLA) and polylactic-glycolic acid(PLGA) with those of nonresorbable ePTFE bdmer. Thirty two patients(25 to 59 years old) with one radiographically evident intrabony lesion of probing depth > or =6mm participated in a Gmonth controlled clinical trial. The subjects were randomly divided into three independent groups. The fist group(n=8) received a ePTFE barrier. The second group (n=12) received a resorbable PLA/PLGA barrier. The third group (n=12) received a resorbable PLA/PLGA barrier combined with an alloplastic bone graft. Plaque index (PI), gingival index(GI), probing depth(PD) , gingival recession, clinical attachment level(CAL), and tooth mobility were recorded prior to surgery and at 3,6 months postsurgery. Statistical tests used to analyze these data included independent t-test, paired t-test, one-way ANOVA. The results were as follows : 1. Probing depth was significantly reduced in all groups at 3,6 months postsurgery and there were not significant differences between groups. 2. Clinical attachment level was significantly increased in all groups at 3, 6 months postsurgery and there were not significant differences between groups. 3. There were not signifiicant differences in probing depth, clinical attachment level, gingival recession, tooth mobility between second group (PLA/PLGA barrier) and third group (PLA/RLGA barrier combined with alloplastic bone graft) 4. Tooth mobility was not significantly increased in all groups at 3,6 months postsurgery and there were not significant differences between groups. In conclusion, PLA/PLGA resorbable barrier has similar clinical potential to ePTFE barrier in GTR procedure of intrabony pockets under the present protocol.

The effects of composit grafts of allogenic decalcified freeze Dried bone and calcium sulfate on the healing of 1-wall intrabony defects in dogs / 대한치주과학회지

The present study evaluates the effects of calcium sulfate and DFDB on alveolar bone regeneration and cementum formation and connective tissue adhesion in intrabony angulated 1 wall defects of dogs. Four millimeter-deep angulated one-wall intrabony defects were surgically created in the mesial & distal aspects of premolars and with flap operaion alone(control group), with calcium sulfate(experimental group 1), with composit graft of 50% calcium sulfate and 50% DFDB(experimental group 2), with DFDB alone(experimental group 3). Histologic analysis following 8 weeks of healing revealed the following results: 1. The lengths of connective tissue adhesion was 1.05+/-0.48mm in the control, 1.30+/-0.67mm in the test group I, 0.97+/-0.22mm in the test group II and 0.93+/-0.15mm in the test group III. There was no statistical significance between control and all experimental groups. 2. Changes in alveolar bone level was 0.97+/-0.27mm in the control group, 1.45+/-0.42mm in the test group I, 2.00+/-0.33mm in the test group II , 1.88+/-0.34mm in the test group III. There was no statistically significant difference between control and experimental group I. There was a statistically significant difference between the control and experimental group II,III.(p<0.05). There was no statistically significant difference between all experimental group. 3. Cementum formation was 1.13+/-0.17mm in the control, 1.78+/-0.31mm in the test group I, 2.17+/-0.38mm in the test group II, 2.15+/-0.47mm in the test group III with statistically significant differences between control group and all experimental group(P<0.05). There was no statistically significant differences between all experimental group. These results suggest that the use of composit graft of 50% calcium sulfate and 50% DFDB and DFDB alone in angulated 1 wall intrabony defects has little effects on connective tissue adhesion, but has significant effects on new bone and new cementum formations.