Clinical and microbiologic effects of subgingival controlled-release delivery of chlorhexidine chip in the treatment of periodontitis: a multicenter study

BACKGROUND: The main therapeutic approach for periodontal diseases is mechanical treatment of root surfaces via scaling and root planing (SRP). Multicenter clinical trials have demonstrated that the adjunctive use of a chlorhexidine (CHX) chip is effective in improving clinical results compared to SRP alone. However, some recent studies failed to confirm these clinical results, and conflicting results were reported regarding the effects of the CHX chip on subgingival microflora. The aim of this study was to provide further data on the clinical and microbiologic effects of CHX chips when used as an adjunct to SRP. METHODS: A total of 116 systemically healthy individuals with moderate to advanced periodontitis, aged 33 to 65 years, were recruited from the Departments of Periodontology of four Italian universities. For each subject, two experimental sites were chosen that had probing depths (PD) > or =5 mm and bleeding on probing (BOP) and were located in two symmetric quadrants. These two sites were randomized at the split-mouth level, with one receiving SRP treatment alone and the other receiving treatment with SRP plus one CHX chip (SRP + CHX). PD, relative attachment level (RAL), and BOP were evaluated at baseline, prior to any treatment, and after 3 and 6 months. Supragingival plaque and the modified gingival index were evaluated at baseline and after 15 days and 1, 3, and 6 months. Subgingival microbiologic samples were harvested at baseline and after 15 days and 1, 3, and 6 months, cultured for total bacterial counts (TBCs), and investigated by polymerase chain reaction analysis for the identification of eight putative periodontopathogens. RESULTS: When all of the pockets were considered, the PD and RAL were significantly less at 3 and 6 months compared to the baseline scores (P <0.01) for both treatments. Moreover, the PD was reduced in the SRP + CHX treatment group compared to the SRP treatment group at 3 and 6 months, whereas the RAL was similar for both treatments at 3 months and was reduced in the SRP + CHX treatment group at 6 months. The differences in PD reductions between the treatments were 0.30 and 0.55 mm at 3 and 6 months, respectively (P <0.01); for the RAL gain, the differences were 0.28 and 0.64 mm, respectively (P <0.001). The TBCs decreased significantly with both treatments. A similar, although less evident, pattern was noted when only the pockets with an initial PD > or =7 mm were considered. The percentage of sites positive for BOP was similar between the treatments at each time point. At 15 days and 1 month, the TBC for the SRP + CHX treatment group was significantly lower than for the SRP treatment group (P <0.01 and P <0.05, respectively). Over time, both treatments generally reduced the percentages of sites positive for the eight putative periodontopathic bacteria, although greater reductions were seen often for the SRP + CHX treatment group. CONCLUSIONS: The adjunctive use of the CHX chip resulted in a significant PD reduction and a clinical attachment gain compared to SRP alone. These results were concomitant with a significant benefit of SRP + CHX treatment on the subgingival microbiota.     

Long-term results of mandibular reconstruction with autogenous bone grafts and oral implants after tumor resection

Objectives: (a) To evaluate retrospectively the clinical outcome of non‐vascularized bone grafts used for the reconstruction of mandibular defects following tumor resection; (b) to evaluate the clinical outcome of implants and implant‐supported prostheses placed in the reconstructed areas; and (c) to evaluate patients' satisfaction regarding function and esthetics after oral rehabilitation. Material and methods: In a 9‐year period (1995–2003), 29 patients affected by mandibular tumors involving to tooth bearing areas were treated by means of tumor resection and immediate or delayed reconstruction with autogenous non‐revascularized calvarial or iliac bone grafts. Among these patients, 16 patients were selected for dental rehabilitation of the lost dentition with implant‐supported 3fixed prosthese333s. For to 7 months later, the patients received 60 oral implants for the prosthetic rehabilitation of the reconstructed edentulous areas. Results: No total failure of the graft was observed, while partial loss of the graft was observed in one patient. The mean follow‐up of patients after the start of prosthetic loading of implants treated was 94 months (range: 36–132 months). Two patients dropped out of the follow‐up after 3 and 4 years of observation, respectively. Two implants were removed due to loss of osseointegration, while two implants, although still integrated, presented peri‐implant bone resorption values higher than those proposed by Albrektsson et al. for successful implants. Cumulative survival and success rates of implants were 96.7% and 93.3%, respectively. Conclusion: Results from this study demonstrated that bone defects following resection of mandibular tumors can be predictably reconstructed with autogenous bone grafts taken from the calvarium or the anterior iliac crest. It has also been shown that the long‐term survival and success rates of implants placed in the reconstructed areas (96.7% and 93.3%, respectively) may guarantee an excellent prognosis of implant‐supported prostheses.     

A preliminary protocol for multi-professional centers for the determination of signs and symptoms of temporomandibular disorders

The objective of the present study was to test a protocol for the quantification of the frequency and severity of signs and symptoms of temporomandibular disorders (TMD) according to patient perception during two phases of investigation. The protocol was developed based on the signs and symptoms most frequently reported in the literature and on the circumstances in which they produce discomfort. Eighty-four patients diagnosed with TMD by functional examination of the masticatory system responded to the protocol questions and indicated the severity of signs and symptoms using an eleven point numerical scale (Phase 1). Forty-two patients were fitted with an occlusal splint (treated group) and the remaining participants did not use a splint (control group). The protocol questions were asked after 50 days of treatment (Phase 2). Based on the results of nonparametric statistical analysis, the incidence of signs and symptoms was high in Phase 1 and significant, with no difference between the groups, whereas the treated and control groups differed in Phase 2. A comparison between Phases 1 and 2 showed that only the treated group presented a reduction in the severity of signs and symptoms. The study showed that using this protocol, it is possible to define the frequency and severity of symptoms as well as the effect of the treatment. The advantage of this protocol is that it would complement the data obtained using clinical examination with information provided by the patient in a measurable manner.     

Prevalence and distribution of developmental enamel defects in the primary dentition of pre-school children

Developmental defects of the enamel (D.D.E.) are changes in the deciduous dentition that have been little studied in Brazil, although they lead to aesthetic problems, dental sensitivity and may be predictors of dental caries. The objective of this study was to estimate the prevalence and distribution of D.D.E. in the deciduous dentition of pre-school children in the municipality of Itajaí, Santa Catarina, in 2003. A cross-sectional study was carried out with a sample of 431 children aged 3 to 5 enrolled in public day care centres. All of the teeth were examined and the enamel defects were assessed according to the Modified DDE Index (FDI, 1992). The prevalence of D.D.E. was 24.4% (CI 95% 20.3-28.5). Diffuse opacities were the most common defects found (17.9%), followed by hypoplasia (11.1%) and demarcated opacities (6.1%). The most affected teeth were the second molars (44.4%), followed by the first molars (23.5%). Defects were observed more frequently in the upper arch (58.2%). Assessing enamel hypoplasia separately, a prevalence of 15.1% (CI 95% 11.7-18.5) was observed, with the most affected teeth being the canines (33.6%) and second molars (33.6%). One quarter of the pre-school children presented enamel defects, with diffuse opacities being the most prevalent ones.     

Marginal Leakage of a New Adhesive Restorative System: A Preliminary In Vivo Investigation

The efficacy of newly developed adhesive restorative materials is commonly described by in vitro test results such as bond strength and microleakage data. Due to the inconsistency often found between in vitro testing and in vivo performance, the purpose of the present investigation was to restore teeth scheduled for extraction in vivo with an experimental restorative bonding system and to evaluate the microleakage of the restorations by common laboratory techniques following extraction after 3 months of clinical service. Two restorations were placed in each of seven anterior teeth, one in the middle of the labial enamel portion and the other labially extending over the cementoenamel junction (CEJ). Six of the seven fillings completely surrounded by enamel showed no microleakage. However, two of the restorations crossing the CEJ revealed microleakage originating from the cervical margins. In spite of the small number of fillings assessed, the experimental enamel-dentin adhesive compound tested is preliminarily considered a promising new system.     

Surface analysis and effects on interfacial bone microhardness of collagen-coated titanium implants: a rabbit model

PURPOSE: The aim of this study was to evaluate the surface chemistry and the microhardness at the implant-bone interface using a recently developed collagen-coated titanium implant in a short-term rabbit model. MATERIALS AND METHODS: Surface chemistry was evaluated by x-ray photoelectron spectroscopy (XPS), while in vivo studies involved 4-week implants mid-diaphysis in the lateral femurs of adult male rabbits. After conventional embedding and evaluation of histologic sections, the resinembedded blocks containing the implanted screws were used to measure bone hardness by means of an indentation test. RESULTS: Decomposition of the C1s peak obtained by XPS analysis confirmed that surface-immobilized collagen retained all the molecular features of the control, nonimmobilized reference. As to microhardness measurement, newly formed bone at the collagen-coated-implant/bone interface was significantly harder than bone at the interface of the uncoated control implant and bone. DISCUSSION: These results suggested that collagen coating significantly improves bone maturation and mineralization at the interface in comparison with uncoated commercially pure titanium. Surface modification of titanium implants by collagen coating has recently been discussed as a promising approach to the biochemical modification of implant surfaces. The present results support previous histologic findings and demonstrated that the biomolecular layer linked over the titanium implant can increase the bone healing rate, at least in this animal model. CONCLUSIONS: The present microhardness measurement at the bone-implant interface showed that collagen coating can significantly improve bone maturation and mineralization at the interface in comparison with uncoated commercially pure titanium, confirming and substantiating previous findings by histomorphometric measurements from the same model.     

Microtensile bond strength tests: scanning electron microscopy evaluation of sample integrity before testing

The failure of a certain number of microtensile specimens during their preparation and before loading is a common and undesirable occurrence. This study was aimed at observing, under a scanning electron microscope, enamel and dentin microtensile specimens, in order to find structural faults that might be responsible for their premature failure. In a sample of 80 sticks, none of the specimens was found to be free of defects. These may consist of microcracks in enamel, most often at the periphery of the stick, or in dentin at the level of hybrid layer. Gaps were often seen at the interfaces between the substrates. Voids were sometimes visible within the resin composite thickness. Enamel specimens tended to exhibit more defects than dentin specimens. It is fair to suspect that, because of the brittleness of the tissue, enamel microtensile specimens are intrinsically more prone to failure, thus yielding bond strengths which are not significantly higher than those measured on dentin specimens. This leads one to question the reliability of the microtensile method for testing adhesion on enamel. It seems sensible to develop a method for a quantitative assessment of specimens integrity before loading as a possible predictor for their performance under load.     

Composite-to-composite microtensile bond strength in the repair of a microfilled hybrid resin: effect of surface treatment and oxygen inhibition

PURPOSE: To compare the 24-h microtensile bond strength of a microfilled hybrid composite to the same material after mechanical and/or chemical treatment and assess the effect of oxygen inhibition on the composite-composite bond. MATERIALS AND METHODS: Forty composite cylinders of Gradia Direct Anterior (GC) were prepared and stored 24 h prior to the following surface treatments: 50-microm aluminum oxide air abrasion and 37% phosphoric acid etching (group 1); hydrochloric acid and 6.9% hydrofluoric acid etching (group 2); diamond bur roughening and 37% phosphoric acid etching (group 3); diamond bur roughening (group 4). In all groups, Prime & Bond NT (Dentsply De Trey) was applied and light cured in air or under a nitrogen atmosphere, prior to layering a buildup of the repairing resin composite. Microtensile bond strength measurements were performed. Data were statistically analyzed with two-way ANOVA and Tukey's test (alpha = 0.05). RESULTS: The curing atmosphere did not significantly influence the interfacial strength (p < 0.05). Surface treatment significantly affected the composite-composite bond (p > 0.05). Air abrasion, regardless of curing atmosphere, resulted in the strongest bond (p < 0.05). The other treatments were comparable. CONCLUSION: Air abrasion and the application of a bonding agent offer satisfactory bond strengths for composite repair. The oxygen inhibition layer on a light-cured adhesive is not crucial to the success of the 24-h composite-composite bond.