Progression of periodontitis in a sample of regular and irregular compliers under maintenance therapy: a 3-year follow-up study

Background: To our knowledge, prospective studies (matched for sex, smoking, and diabetes) that investigated the influence of compliance in the progression of periodontitis and tooth loss in periodontal maintenance therapy (PMT) programs were not previously reported. Methods: A total of 58 regular complier (RC) and 58 erratic complier (EC) individuals were recruited from a prospective cohort with 238 patients under PMT and matched by sex, diabetes, and smoking habits. A full‐mouth periodontal examination that included bleeding on probing (BOP), probing depths (PDs), clinical attachment levels, and number of teeth were determined at all PMT visits during a 3‐year interval. The influence of variables of interest was tested through multivariate logistic regression. Results: The progression of periodontitis and tooth loss was significantly lower among RC compared to EC patients. A higher progression of periodontitis was observed among EC patients who smoked. The final logistic model for the progression of periodontitis in the RC group included smoking (odds ratio [OR]: 4.2) and >30% of sites with BOP (OR: 2.8), and the final logistic model for the progression of periodontitis in the EC group included smoking (OR: 7.3), >30% of sites with BOP (OR: 3.2), PDs of 4 to 6 mm in 10% of sites (OR: 3.5), diabetes (OR: 1.9), and number of lost teeth (OR: 3.1). Conclusions: RC patients presented a lower progression of periodontitis and tooth loss compared to EC patients. This result highlighted the influence of the pattern of compliance in maintaining a good periodontal status. Moreover, important risk variables such as smoking and diabetes influenced the periodontal status and should be considered when determining the risk profile and interval time for PMT visits.     

Effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin

This study evaluated the effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin. Bovine roots were endodontically treated, and 10 roots were used for each adhesive application mode: PB (Prime&Bond 2.1), PB + SC (Self-cure activator), PB + SBM (Scotchbond Multi-purpose adhesive system), BB (Brush&Bond), BB + CAT (chemical catalyst), and BB + SBM. The translucent Light-Post and Aestheti-Post were cemented. The roots/cemented posts were transversally sectioned to originate three thirds (cervical, middle, and apical). The push-out test was performed, and the failure mode of fractured specimens was analyzed. There was no difference between the fiber posts. For PB and BB, the use of hydrophobic adhesive resin SBM increased post bond strength. The use of SC and CAT catalyst did not affect the push-out bond strength values. The apical third presented the lowest bond strengths.     

Mechanical properties of visible light-cured resins reinforced with hydroxyapatite for dental restoration.

OBJECTIVES: The purpose of this study was to measure and analyze the mechanical properties of several composite materials designed for dental restoration. METHODS: The materials were composed of a visible light-curing monomer mixture (either Bis-GMA+TEGDMA or Bis-GMA+HEMA) as a matrix and hydroxyapatite (either microscopic or nanoscopic particles) as a reinforcing filler. The surface of the hydroxyapatite particles was modified by using a coupling agent (citric, malic, acrylic or methacrylic acid). Five specimens of 14 different composites were prepared for each mechanical test: flexural strength, Young's modulus and Vickers hardness. Mean values and standard deviations were calculated, and ANOVA and Student Newman Keuls multiple comparison tests were applied (P < 0.05). RESULTS: The addition of 50-60 wt% of hydroxyapatite particles to the unfilled monomer mixtures led to the increase of both Young's modulus and surface hardness of the material, while the flexural strength decreased. In general, when microscopic instead of nanoscopic hydroxyapatite was used as a reinforcing filler, mechanical properties were favored. The mechanical properties were also improved by adding citric, acrylic or methacrylic acid as a coupling agent. CONCLUSIONS: An adequate surface modification of the hydroxyapatite particles conferred enhanced mechanical properties to the final dental composite. Microscopic-hydroxyapatite particles are preferred to nanoscopic ones.     

Condensation silicones: do new materials really presents better dimensional stability?

The aim of this study was evaluate the dimensional stability of some condensation silicones. The following materials were studied: Coltex/Coltoflax - Coltène, Speedex - Coltène, and Optosil Comfort/Xantopren VL Plus - Kulzer. They were evaluated by dimensional analysis and gas chromatography (GC) performed at the following times: T0, T1, T2, T3, T4, and T5 (immediately after setting, thirty minutes, two hours, twenty four hours, seventy two hours, and seven days after setting, respectively). The dimensional changes were measured directly in the molds using a Mitutoyo microscope. The Coltex fine/Coltoflax and Optosil Comfort/Xantopren VL Plus materials presented dimensional stability for up to thirty minutes after molding, while the Speedex material remained stable for up to two hours after molding. The gas chromatography experiment demonstrated that these materials release ethanol even after clinical setting.     

The specific panoramic radiographic signs and their relation with inferior alveolar nerve injuries after mandibular third molar surgery

The aim of the authors was to describe the classic specific panoramic signs (indicating a close spatial relationship between dental canal and third molar's root) on panoramic radiographic images and determine their role in the risk assessment, predicting inferior alveolar nerve (IAN) paresthesia after lower third molar removal. The authors represented an informative case, where the IAN was visible during the surgery. The exact knowledge of classic panoramic radiographic signs should help the determination of "high risk" cases predicting IAN paresthesia after mandibular third molar removal. The authors keep panoramic radiography rather a routine than the most superior diagnostic tool in third molar surgery.     

Bonding properties of universal adhesives to root canals prepared with different rotary instruments

Statement of problem

Preparation of coronal dentin by using a diamond rotary instrument usually results in higher bond strength values than preparation with tungsten carbide burs, but information is lacking about the influence of rotary instruments on root canals before the bonding of fiber posts.

The effect of the surface morphology of Ti-implants on the proliferation activity of fibroblasts and osteoblasts

It is known that surface morphology greatly influences the osseointegration of dental implants. The goal of the experiments conducted by the authors was to study in vitro the effect of various surface modifications on the activity of bone and connective tissue cells. In the experiments they introduced NIH3T3 fibroblast and MCH3T3 osteoblast cells were cultured the surface of ten titanium disks with various morphology in 24-multiwell plates. The cells were let grow on the surface of the disks for two days in a culture medium. One group of the disks underwent scanning electronmicroscopy and the changes in the number and form of cells on the surfaces were studied under various magnifications. From the surface of the second group the cells were lysed and were counted in a Bürker's chamber. After counting the cells they were lysed in a lysis buffer and their protein concentrations were measured with the help of a spectrophotometer. The authors found that only a morphological study of the cells is possible under SEM, they could not detect a quantitative difference in the number or activity of the cells. Upon counting the cells and determining their protein concentration the best result were yielded by the surface roughened by aluminium oxide. In growing fibroblasts the titanium oxide treated surfaces provided good results, while in the case of the osteoblasts the laser treated disks were more successful.