Effects of orthodontic tooth extrusion produced by different techniques, on the periodontal tissues: a histological study in dogs.

OBJECTIVE: The aim of this study was to compare the periodontal tissue changes resulting from different methods of orthodontic tooth extrusion in dogs. MATERIALS AND METHODS: Notches were surgically prepared in the root surface at the bone crest level of the first premolars of mongrel dogs. After 37 days, extrusion of the first lower and upper premolars was randomly performed by 3 different methods: conventional orthodontic extrusion (OE); open flap debridement performed immediately before orthodontic extrusion (OF); and orthodontic extrusion associated with weekly fiberotomy and scaling (FS). For all groups, extrusion was performed for 21 days followed by one-month retention and sacrifice. Periodontal parameters, descriptive histology, and histomorphometric analyses were performed at the end of the experimental period. RESULTS: The median extrusion was 2.25 in the fiberotomy group, 2.0 mm in the open flap group and 1.0 mm in the orthodontic extrusion group with no significant differences between groups. The highest distance between reference notch and bone crest was observed in the fiberotomy group (p < 0.05). Histologically, radicular resorption repaired with cellular cementum was detected in all groups. CONCLUSIONS: Tooth extrusion was successfully achieved with all of the different methods of orthodontic tooth extrusion with no statistical significance between techniques. The fiberotomy approach was effective in avoiding coronal displacement of periodontal tissues. Fiberotomy associated with scaling should be indicated if the objective of the treatment is extrusion without periodontal tissue displacement.

Topical application of lectin Artin M improves wound healing in defects created in the palatal mucosa: an in vivo study in dogs.

Previous studies have shown that topical application of lectin Artin-M accelerates wound healing in the rat oral mucosa. The aim of this study was to evaluate, by means of histology and immunohistochemistry (IHC) the effects of Artin-M on wound healing in the palatal mucosa in dogs. Three full thickness wounds of 6 mm diameter were surgically created in the palatal mucosa of twenty dogs and randomly divided into three groups according to one of the treatment assigned: Group C-Control (coagulum); Group A-Artin-M gel; Group V-Vehicle (carboxymethylcellulose 3%). Each animal received all the three experimental treatments. Afterwards, four animals were killed at 2, 4, 7, 14 and 21 days post-surgery. Wounded areas were photographed and scored for macroscopic evaluation. Biopsies were harvested and used for descriptive histological analysis, proliferating cell nuclear antigen IHC and measurement of myeloperoxidase activity. The results demonstrated faster wound closure in group A in comparison to the other groups in all the periods evaluated. Histological analyses exhibited improved re-epithelialization and collagen fiber formation resulting in faster maturation of granulation tissue in group A compared to the other groups by day 14. Treatment with Artin-M gel significantly induced cell proliferation and increased volumetric density of fibroblasts at day 2 and 4 (p < 0.05). Neutrophil infiltration in group A was significantly higher than the other groups (p < 0.05) at the same time points. Collectively, our findings demonstrated that Artin-M may potentially favor wound healing on palatal mucosa lesions via recruitment of neutrophils and promotion of cell proliferation.

Effect of Subgingival Irrigation with Different Substances in the Treatment of Periodontal Disease. A Histometric Study in Rats.

The aim of this study was to evaluate the histometric effects of subgingival irrigation with different solutions as adjuvant for the treatment of periodontal disease in rats. Periodontal disease was induced by ligature in the first lower molars of 91 Wistar rats over the course of 28 days. After removal of the ligatures, the animals were subjected to scaling and root planing, followed by subgingival irrigation with different solutions (0.9% saline, 0.2% chlorhexidine, 0.1% and 0.5% sodium hypochlorite and 11% propolis extract). The animals were sacrificed 7 and 14 days after the treatment and tissue was processed for histometric analysis for evaluation of bone support and epithelial migration. The histometric analysis showed no statistically significant differences between the group treated with scaling and groups treated with subgingival irrigation (p > 0.05) regarding bone support and epithelial migration. Similarly, significant differences were not found among the different solutions used for subgingival irrigation. This study agrees with the position of the American Academy of Periodontology, which states that there is insufficient evidence to indicate the routine use of subgingival irrigation as adjuvant to periodontal treatment.

Connective tissue graft as a biological barrier for guided tissue regeneration in intrabony defects: a histological study in dogs.

BACKGROUND: The use of the autogenous periosteal graft as biological barrier has been proposed for periodontal regeneration. The aim of this study was to evaluate the histometric findings of the subepithelial connective tissue graft as barrier in intrabony defects compared to a bioabsorbable membrane. METHODS: Three-walled intrabony defects were created surgically in the mesial aspect of the right and left maxillary canines in five healthy mongrel dogs. The defects were chronified, and two types of barriers were randomly carried out for guided tissue regeneration in a split-mouth design: the test group with a subepithelial connective tissue graft and the control group with a bioabsorbable membrane. The specimens were processed for histometric analyses of the epithelium (E), connective tissue (CT), newly formed cementum (NC), new bone (NB), and total newly formed tissues (NFT). RESULTS: The test side showed smaller mean of NC (3.6 ± 1.2), NB (2.1 ± 0.7), and NFT (7.7 ± 0.8) than the control group (NC 7.3 ± 0.5; NB 5.3 ± 1.3; NFT 10.1 ± 2.2; P < 0.05). No statistically significant differences were verified for E (test 3.1 ± 2.0; control 2.8 ± 2.1; P > 0.05) and CT (test 2.5 ± 1.1; control 2.0 ± 0.5; P > 0.05) between groups. CONCLUSION: The bioabsorbable membrane was more effective in maintaining the space for periodontal regeneration than periosteal connective graft when used as barrier. CLINICAL RELEVANCE: The bioabsorbable membrane showed more favorable regenerative results in intrabony defects in dogs than the subepithelial connective tissue graft as biological barrier.

The efficacy of 2 different doses of dexamethasone to control postoperative swelling, trismus, and pain after third molar extractions.

This article addresses the effect of 2 different concentrations (4 and 12 mg) of dexamethasone to control pain, swelling, and trismus after third molar surgery. A clinical study was conducted with 27 male and female patients, all presenting with bilaterally displaced mandibular third molars. The treatment protocol required a surgical removal of each tooth in 2 separate operations. The patients were given a preoperative dose of dexamethasone-4 mg for one surgery, 12 mg for the other. The choice of which side would be operated on first and which dose of dexamethasone would be taken was performed randomly, under double-blind conditions. The trismus was assessed by measuring the interincisal distance. Pain intensity was measured both by the amount of painkillers (acetaminophen 750 mg) taken postsurgery and by the Visual Analogue Pain Scale. Data were collected 1 hour preoperative, then at 24 and 48 hours postoperative. A statistical analysis (student's t, Wilcoxon and Friedman tests) of the results showed no significant differences (α = 0.05) between the analyzed variables for the 2 doses of dexamethasone (4 and 12 mg).

Wound healing of dehiscence defects following different root conditioning modalities: an experimental study in dogs.

OBJECTIVE: The purpose of this study was to investigate the periodontal healing pattern of dehiscence-type defects following different chemical root conditioning modalities. MATERIALS AND METHODS: Buccal osseous dehiscence defects were created on six teeth of seven dogs. After dental plaque accumulation, defects were treated with sterile saline solution (control group) or one chemical conditioning modality: citric acid (CA group), ethylenediaminetetraacetic acid (EDTA group), tetracycline (TTC group), citric acid + tetracycline (CA + TTC group), or tetracycline + citric acid (TTC + CA group). After 3 months of healing, clinical parameters were evaluated, and the animals were killed. Histological sections were processed, and a computer-assisted histometric analysis was used to evaluate the formation of new cementum, new bone, and epithelial apical migration. RESULTS: All treatments yielded significant improvements in terms of probing depth decrease and clinical attachment level gain compared to baseline values; however, without significant differences among the groups (p > 0.05; one-way ANOVA). The highest amount of new cementum was noted in the EDTA group (3.72 ± 0.83 mm, 77.6 %), while the lowest amount of new bone was observed in the TTC group (0.7 ± 0.94 mm, 14.3 %). However, no statistically significant differences could be observed among the groups regarding epithelial apical migration, new cementum, and alveolar bone formation (p > 0.05). CONCLUSION: Chemical root surface conditioning did not promote any significant improvement in periodontal healing pattern of dehiscence-type defects in dogs. CLINICAL RELEVANCE: Chemical root surface conditioning after surgical debridement did not promote positive or negative effects on periodontal healing pattern of dehiscence-type defects.

Effects of ultrasonic, electric, and manual toothbrushes on subgingival plaque composition in orthodontically banded molars.

INTRODUCTION: Orthodontic appliances hinder mechanical plaque control. In this study, we evaluated the effect of self-performed supragingival plaque removal with ultrasonic, electric, and manual toothbrushes on subgingival plaque composition in orthodontically banded molars. METHODS: Twenty-one patients wearing fixed orthodontic appliances were assigned to this single-blind crossover study. Samples of subgingival plaque were collected from banded molars, before and after each toothbrush usage period, for quantification of 22 bacterial species by the checkerboard DNA-DNA hybridization method. For each crossover, patients used a toothbrush for 30 days, followed by a washout period of 14 days. RESULTS: The prevalence of Tannerella forsythia decreased significantly after a month of electric brush usage. In the manual brush group, the prevalences of Selenomonas noxia, Streptococcus sanguinis, and Prevotella melaninogenica also decreased significantly. However, there were no significant differences in the prevalences and levels of bacteria after usage of the ultrasonic brush. Intergroup comparisons showed no statistical differences among the 3 brushes for the microbiologic parameters. CONCLUSIONS: All 3 brushes generally reduced bacterial prevalences, and, although electric and manual toothbrushes showed some isolated significant variations, we found no superiority with any toothbrush type when used three times daily for 2 minutes on microbiologic parameters in orthodontically banded molars.

Orthodontic movement after periodontal regeneration of class II furcation: a pilot study in dogs.

PURPOSE: The effect of orthodontic movement on the periodontal tissues of maxillary second pre-molars, after regenerative treatment for class II furcations, was evaluated in four mongrel dogs. MATERIAL AND METHODS: Class II furcation lesions were created. After 75 days they were treated with bovine bone mineral matrix and guided tissue regeneration with absorbable membrane. After 2 months of daily plaque control, each of the dog's furcation pre-molars was randomly assigned to a test or control group. Orthodontic appliances were placed on both sides of the maxilla using third pre-molars and canines as anchorages. In the test group, bodily orthodontic movement of the second pre-molars was performed in the mesial direction for 3 months while control pre-molars remained unmoved. The dogs were sacrificed for histometric and histologic analyses. RESULTS: There were no statistically significant differences between the two groups in total bone and biomaterial areas or linear extension of periodontal regeneration on the radicular surfaces. In the test group, however, there was a tendency to a greater quantity of bone and a lesser quantity of biomaterial. CONCLUSION: The orthodontic movement was not pre-judicial to the results obtained with the regenerative periodontal treatment.