Connective tissue repair in circumferential periodontal defects in dogs following use of a biodegradable membrane

A biodegradable polylactic acid membrane was evaluated for its ability to enhance periodontal regeneration. In 8 Labrador dogs, circumferential defects were created around the maxillary 1st premolars. The defects were combination "1-wall vertical and horizontal". A membrane was adjusted to cover the defect on one side of the jaw, while the contralateral tooth served as control without membrane. After 3 months, healing was evaluated histologically. The results demonstrated that the amount of connective tissue repair with newly formed cementum approximated 50% of the defect height for both test and control groups. Thus, no advantage to the use of membrane was found, which is contradictory to the findings of our previous dog study using the same biodegradable membrane. The possible reasons for this difference in results are discussed relative to suggested mechanisms for membrane effects in periodontal regeneration.     

Evaluation of tongue coating indices

AIM: The purpose of this study was to determine inter-examiner reproducibility of two modified Winkel tongue coating indices and to study the relationship between each of these two indices and the amount of tongue coating as determined by wet weight of scrapings from the dorsum of the tongue. MATERIALS AND METHODS: Twenty-five participants were selected for the study from among dental students. The selection was made to assure that a wide range of degrees of tongue coating were represented. Two independent examiners scored the tongue coatings using the two modified Winkel tongue coating indices (mWTCI 1 + 2 and mWTCI 2). After completion of index recordings, tongue scrapings were performed by one of the examiners. RESULTS: Inter-examiner reproducibility of mWTCI 1 + 2 and mWTCI 2 using Pearson's coefficients of correlation amounted to r = 0.48 and 0.93 respectively. Overall, mWTCI 2 showed higher correlations to wet weight of tongue scrapings than mWTCI 1 + 2. CONCLUSION: The mWTCI 2 was found to be highly reproducible and also valid as related to wet weight of tongue scrapings. This index would seem suitable for further studies on tongue coatings; effect of tongue cleaning; and rate of reformation of coatings after cleaning.     

Periodontal repair in dogs Effect of heparin treatment of the root surface

Studies on periodontal repair to denuded root surfaces have suggested that initial clot adhesion to the root surface may be important for the nature of subsequent healing. To study this hypothesis, circumferential periodontal defects, approximately 5 mm in vertical dimensions, were surgically created and immediately treated around the mandibular premolars in 4 beagle dogs. Prior to wound closure, the root surfaces were treated with either the anticoagulant heparin or with saline. Tissue blocks were obtained at sacrifice 4 weeks after surgery. Histometric analysis showed that connective tissue repair to the root surface averaged 50% of the defect height for heparin-treated teeth as compared to 95% for saline-treated teeth. Junctional epithelium amounted to an average of 33% of the defect height in heparin-treated teeth in contrast to 5% following saline treatment. It can be concluded that heparin treatment of the root surface compromises connective tissue repair, confirming clot adhesion as one prerequisite for connective tissue repair of periodontal defects.     

Reproducibility of microbiological samples from periodontal pockets

Duplicate microbiological samples, were taken 1 week apart using the paper point technique from a total of 112 untreated periodontal pockets greater than 6 mm deep in 16 adult periodontal patients. Duplicate samples were also obtained from these sites 6 months following a therapy of oral hygiene instruction and supra- and subgingival debridement. The reproducibility of the total viable counts and the reproducibility of the proportions of various groups or species of microorganisms were studied from these duplicate samples. The results demonstrated an acceptable degree of reproducibility for the recovery of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis. For the total viable counts and for the other investigated bacterial groups, including Bacteroides intermedius, unacceptable levels of reproducibility were observed.     

Subjective criteria and probing attachment loss to evaluate the effects of plaque control and root debridement

11 adult patients with moderate to advanced periodontitis were treated with oral hygiene instruction and an initial, single episode of root debridement. Before therapy, 3 independent clinicians examined all patients and identified sites that in their opinion probably would not respond to the therapy and would continue to lose attachment. On 2 occasions, 3 and 12 months later, the clinicians re-examined and re-evaluated all patients and all sites. The results of therapy were also monitored by probing attachment level measurements performed every 3rd month. All 11 patients completed 24 months of follow-up, and 6 subjects were available until 36 months. Sites with probing attachment loss after 12, 24 and 36 months were identified using linear regression analysis and compared to the clinicians' prediction of probing attachment loss. The results demonstrated a limited agreement between probing attachment loss determined by linear regression and the clinicians' predictions of probing attachment loss. It appears that the traditional clinical signs and factors used to forecast and identify periodontal disease activity are only moderately associated with probing attachment loss. This suggests that attachment loss may be caused by several factors, at least following initial therapy. The progression of an inflammatory disease of microbial etiology may be only 1 of such causes. Further studies are needed to clarify the nature and cause of probing attachment loss.     

Treatment of periodontal furcation defects Coronally positioned flaps versus dura mater membranes in class II defects

Abstract Mandibular class II furcation defects in 19 subjects were treated using 2 different methods of wound closure. In 16 of the defects, the wound was closed with a coronally positioned surgical flap secured by crown-attached sutures. In 15 of the defects, a collagenous membrane (freeze-dried dura mater) was placed to cover the exposed defect, followed by suturing of the surgical flap at the level of the alveolar crest. After use of a coronally positioned flap, an average of 70% of the defect volume became filled with bone, with complete closure by bone fill for 9 of the 16 treated defects. After use of dura mater membrane, 38% of the defect volume was filled with bone, with complete bony closure for 3 of the 15 treated defects. The results following use of coronally positioned flaps support our previous findings and the potentials of this technique. The results following use of dura mater membranes, together with recently reported risk for spread of virus with dura implants, do not justify the use of dura mater for these regenerative purposes.     

Scores of plaque, bleeding, suppuration and probing depth to predict probing attachment loss 5 years of observation following nonsurgical periodontal therapy

The purpose of the present study was to determine the diagnostic value of clinical scores of supragingival plaque, bleeding, suppuration and probing depth to predict probing attachment loss in patients on maintenance following nonsurgical periodontal therapy. Non-molar teeth in 39 subjects were monitored and the above scores were repeatedly obtained throughout 5 years of observation following initial treatment. Probing attachment loss between 0-60 months was determined by a combination of linear regression analysis and end-point analysis. The results revealed that all the investigated scores were associated with probing attachment loss. This association was demonstrated by improved diagnostic predictability along with increased frequency or magnitude of the various scores. Also, the diagnostic predictability improved with increase in length of time for recording of the scores. The diagnostic predictability of either accumulated plaque scores and accumulated bleeding scores reached a maximum of about 30%. Residual probing depth greater than or equal to 7 mm reached a predictability of around 50% and increase in probing depth greater than or equal to 1.0 mm reached about 80% after 60 months. Thus, of the clinical scores investigated, increase in probing depth was found to be most valuable in predicting probing attachment loss.     

Effect of non-surgical periodontal therapy

Incisors, cuspids and premolars in 49 patients with advanced chronic periodontitis were treated with initial, non-surgical periodontal therapy. The results were monitored by probing attachment level measurements at 6 sites of each tooth every 3rd month during a period of 24 months. A series of 9 probing attachment level measurements for each site was subjected to linear regression analysis. The slope of the regression line, the projected probing attachment loss during the 24-month interval (delta y) and the probability level of the slope were calculated for each site. 2 groups of sites with probing attachment loss were identified: group 1: sites with delta y greater than 1.5 mm and p less than 0.05; group 2: sites with delta y greater than 1.0 mm and p less than 0.05. Group 1 included 120 sites (5%) and group 2 included 265 sites (10%) of the total of 2532 available sites. In both groups, probing attachment loss was more frequently noticed for sites with an initial probing depth less than or equal to 3.5 mm than for sites with initial probing depth greater than or equal to 7.0 mm. The finding that the majority of sites with probing, attachment loss was found amongst initially shallow or moderately deep lesions may indicate attachment loss due to trauma associated with therapy rather than loss as a result of a continuing, inflammatory disease process.     

Healing of horizontal circumferential periodontal defects following regenerative surgery in beagle dogs

Regenerative surgery of dog teeth with reduced periodontal support was undertaken to determine: if new connective tissue attachment could be predictably attained back to the level of the cemento-enamel junction; and to what extent the new attachment would be accompanied by bone regeneration, root resorption, and ankylosis. The alveolar bone around mandibular premolars was surgically reduced up to 6 mm from the cementoenamel junction. The denuded root surfaces were exposed to the oral environment during a period of 3 months without plaque control. Regenerative surgery was then carried out employing citric acid root conditioning and coronally positioned flaps. 6 months later, histologic evaluation of the midbuccal and midlingual areas of mesial and distal roots revealed new attachment over extended portions of the root surfaces. In 91 of 120 available surfaces, there was no epithelial downgrowth apical to the cemento-enamel junction. Bone regeneration varied from negligible amounts to complete reformation. However, root resorption and ankylosis were prevalent features. 2 different types of resorptions could be distinguished: those occurring near the cemento-enamel junction (cervical resorption), and those occurring more apically in areas of newly formed bone (ankylosis-associated resorption). Resorption of either or both types was noted for 92 of the 120 surfaces.