Julio Cesar Joly

Clinical and Radiographic Evaluation Periodontal Intrabony Defects Treated With Guided Tissue Regeneration. A Pilot Study

BACKGROUND The aim of this clinical and radiographic study was to evaluate the effect of guided tissue regeneration using a bioabsorbable barrier in the treatment of intrabony defects in humans. METHODS Intrabony osseous defects (2 or 3 walls) around mandibular canines and premolars were treated in 10 systemically healthy patients with ages ranging from 35 to 56 years. Prior to the surgical phase, patients were enrolled in a strict maintenance program including oral hygiene instructions and scaling and root planing (presurgical PI and GI <10%). Patients were seen for professional prophylaxis during the duration of the study. Clinical measurements were performed with an electronic probe at baseline and at reentry 8 months following surgical therapy. Measurements included clinical attachment levels (CAL), gingival margin levels (GML), probing depths (PD), bone defect levels (BDL), and alveolar crest level (ACL). A split mouth design was used. Quadrants were randomly assigned for treatment by GTR (experimental) or open flap debridement alone control). Standardized radiographs were taken at baseline and at reentry. Digital images were analyzed by subtraction to assess changes in area (A) and optical density (OD). Data were evaluated using paired t test. RESULTS Statistically significant differences were found in both groups when comparing baseline and post-treatment values for CAL, GML, PD, and BDL (P <0.01). Greater reductions in BDL and gain in A and OD were observed in the GTR group when compared to control (P <0.01). Both therapies were effective in improving the clinical parameters assessed. CONCLUSION Clinical and radiographic findings from this study demonstrated more bone fill in sites treated with GTR. J Periodontol 2002;73:353-359.

Effect of Tumor Necrosis Factor-?? Gene Polymorphism on Peri-Implant Bone Loss Following Prosthetic Reconstruction

Purpose:The present study investigates the association between a specific polymorphism in the tumor necrosis factor (TNF)-&agr; gene, consisting of allele 2 of TNF-&agr;−308, and peri-implant bone loss following prosthetic reconstruction. Materials and Methods:This case-control study included 36 patients (20 women, 16 men; mean age 46 years) who had used implant-supported prostheses for a minimum of 6 months and a maximum of 31 months. The patients were nonsmoking, white Caucasian Brazilians, in good general health, and were not receiving medication. In the case group, patients exhibited 1 or more implants with a diagnosis of peri-implant bone loss following prosthetic reconstruction; control patients had 1 or more healthy implants. Results:Polymorphism in the TNF-&agr; gene, allele 2 of TNF-&agr;−308, was not associated with an increased risk for peri-implant bone loss following prosthetic reconstruction (P = 0.19; &khgr;2 = 1.71; df = 1), although 21.1% of the subjects carried allele in the control group 2, and 41.2% carried allele 2 in the case group. Conclusions:Polymorphism in allele 2 of the TNF-&agr;−308 gene is not associated with an increased risk for peri-implant bone loss following prosthetic reconstruction. However, further studies based on a greater number of patients are necessary.

Characteristics of implant surface and implant-abutment gap in two- and one-stage systems

The aim of this study was to evaluate under scanning electron microscopy the characteristics of the implant surface and the gap between the components of two- and one-stage systems. Three two-stage implants coated with RBM and three one-stage implants coated with TPS were selected. In the two-stage implants, the esthetic-cone abutments were adapted and screw tightened with 20 N/cm . In the one stage implants, solid abutments were adapted and torque tightened mechanical frictional with 30 N/cm. The specimens were mounted on stubs and analyzed under scanning electron microscopy. The gap in each implant was measured in four different points and repeated three times. The paired Student-t test was applied to detect the difference in the gap extension. The results showed that no significant differences (P > 0.05) were found regarding the gap extension between two- and one-stage systems and that the treatments produced different surface roughness.

Comparação entre fibroblastos gengivais e do ligamento periodontal de um mesmo indivíduo

O objetivo deste estudo foi comparar as caracteristicas morfologicas, o potencial proliferativo e a producao proteica de fibroblastos do ligamento periodontal (FLP) e de fibroblastos gengivais (FG). Os fibroblastos foram cultivados pela tecnica do explante a partir de fragmentos da gengiva e do ligamento periodontal de um mesmo individuo. As celulas foram isoladas e plaqueadas para analise por microscopia de contraste de fase e microscopia optica. O indice de proliferacao celular foi determinado por contagem automatica de celulas e pelo ensaio de incorporacao de bromodioxiuridina (BrdU). A producao de proteina total foi verificada por eletroforese em gel de poliacrilamida e o perfil enzimatico por analise zimografica. Os FLP sao maiores e mais alongados que os FG em condicoes de subconfluencia e confluencia celular. Os FLP demonstraram um potencial proliferativo significantemente maior que os FG. Os perfis proteico e enzimatico foram similares entre os FLP e FG. Os resultados demonstram que os FLP e FG sao diferentes na morfologia e na capacidade proliferativa, porem sao semelhantes na producao proteica.

Influence of transmucosal height on loss of prosthetic abutment torque after mechanical cycling

The aim of this study was to measure and record the universal transmucosal abutment height, and then evaluate whether it influenced loosening of the abutment screw by analyzing the torque and detorque values after mechanical cycling. Thirty-six implants, model CM Unitite, with internal conical connections (3.5 × 10 mm) and respective universal prosthetic abutments (n = 36, 3.25 × 6 mm), were divided into three groups (n = 12 each) with respective transmucosal heights of 0.8, 3.5, and 5.5 mm. Insertion torque of 20 Ncm was used in accordance with the manufacturers specifications. Afterward, the samples were submitted to fatigue tests consisting of 500,000 cycles at a frequency of 2Hz, a dynamic compressive load of 120N, and an angle of 30°. The detorque values were measured with a digital torque meter and tabulated to perform statistical analyses; a level of significance of 5% was adopted. The mean detorque values (SD) obtained were 22.83 (6.30), 22.5 (5.45), and 19.41 (4.69) Ncm for transmucosal abutments with heights of 0.8, 3.5, and 5.5 mm, respectively, and showed no statistically significant difference ( P = .262). The authors of this study concluded that the transmucosal height of prosthetic abutments submitted to mechanical fatigue did not influence the detorque values.

In Vitro Microbiological Analysis of Bacterial Seal in Hybrid Zirconia Abutment Tapered Connection.

Purpose: The aim of this study was to evaluate the bacterial seal at the implant–hybrid zirconia abutment interface and Morse taper–type connections through in vitro microbiological analysis. Materials and Methods: Sixteen implants and their respective abutments were divided into 3 groups: test (10 sets), positive control (3 sets), and negative control (3 sets). In the test group, 10 implants were contaminated with Escherichia coli using a sterile inoculating loop to the inner portion of the implants, followed by torque application to the abutment (30 N·cm). The positive controls were also contaminated, but no torque was applied to the abutment screw. The negative control consisted of uncontaminated sets. All specimens were immersed in test tubes containing 5 mL brain heart infusion (BHI) broth, maintained in a microbiological incubator for 14 days at 37°C under aerobic conditions, and monitored every 24 hours for evidence of bacterial growth. Results: During the 14 days of incubation, no significant increase in the number of cloudy culture media was observed in the test group (P = 0.448). No significant difference in broth turbidity ratio was observed (P > 0.05). Conclusion: Hybrid zirconia abutments can create an effective seal at the tapered abutment–implant interface with a 30-N·cm installation torque.