Cutting characteristics of dental diamond burs made with CVD technology

The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD) diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding type of substrate (enamel and dentin) and direction of handpiece motion. The morphological characteristics, width and depth of the cavities were analyzed and measured using scanning electron micrographs. Statistical analysis using the Kruskal-Wallis test (p < 0.05) revealed that the width and depth of the cavities were significantly greater when they were prepared on dentin. Wider cavities were prepared when the cylindrical CVD bur was used, and deeper cavities resulted from preparation with the spherical CVD bur. The direction of handpiece motion did not influence the size of the cavities, and the CVD burs produced precise and conservative cutting.

Densitometric analysis of the autogenous demineralized dentin matrix on the dental socket wound healing process in humans

The aim of this study was to evaluate the effects of the autogenous demineralized dentin matrix (ADDM) on the third molar socket wound healing process in humans, using the guided bone regeneration technique and a polytetrafluoroethylene barrier (PTFE). Twenty-seven dental sockets were divided into three groups: dental socket (Control), dental socket with PTFE barrier (PTFE), and dental socket with ADDM slices associated to PTFE banier (ADDM + PTFE). The dental sockets were submitted to radiographic bone densitometry analysis and statistical analysis on the 15th, 30th, 60th and 90th days using analysis of variance (ANOVA) and Tukey's test (p ≤ 0.05). The radiographic analysis of the ADDM + PTFE group showed greater homogeneity of bone radiopacity than the Control group and the PTFE group, during all the observation times. The dentin matrix gradually disappeared from the dental socket during the course of the repair process, suggesting its resorption during the bone remodeling process. It was concluded that the radiographic bone density of the dental sockets treated with ADDM was similar to that of the surrounding normal bone on the 90th day. The ADDM was biocompatible with the bone tissue of the surgical wounds of human dental sockets. The radiographic analysis revealed that the repair process was discreetly faster in the ADDM + PTFE group than in the Control and PTFE groups, although the difference was not statistically significant. In addition, the radiographic image of the ADDM + PTFE group suggested that its bone architecture was better than that of the Control and PFTE groups.

Investigation of photo-bleaching through transmittance method in pigmented solution: Understanding possible mechanisms and advantages for photo dental whitening

The dental bleaching is known for many years. Recently a technique employing light has open up new and exciting possibilities. Besides its vast application there are still many important points to be understood about teeth photon bleaching. In this work we present an in vitro experiment to explore the main mechanisms involved during the photon action in tooth whitening. Our results indicated that light at same wavelengths are great absorbed by pigments creating a local heating which considerably increase the bleaching rate. This results in a fast reaction without heating the whole dental structure. We discuss details of our experiment. Work supported by Fapesp and CNPq.

Influence of resin composite insertion technique in preparations with a high C-factor

Objective: To evaluate the marginal microleakage in enamel and dentin/cementum walls in preparations with a high C-factor, using 3 resin composite insertion techniques. The null hypothesis was that there is no difference among the 3 resin composite insertion techniques. Method and Materials: Standardized Class 5 cavities were prepared in the lingual and buccal aspects of 30 caries-free, extracted third molars. The prepared teeth were randomly assigned to 3 groups: (1) oblique incremental placement technique, (2) horizontal incremental placement technique, and (3) bulk insertion (single increment). The preparations were restored with a 1-bottle adhesive (Single Bond, 3M ESPE) and microhybrid resin composite (Z100, 3M ESPE). Specimens were isolated with nail varnish except for a 2-mm-wide rim around the restoration and thermocycled (1,000 thermal cycles, 5°C/55°C; 30-second dwell time). The specimens were immersed in an aqueous solution of 50 wt% silver nitrate for 24 hours, followed by 8 hours in a photo-developing solution and evaluated for microleakage using an ordinal scale of 0 to 4. The microleakage scores obtained from occlusal and gingival walls were analyzed with Wilcoxon and Kruskal-Wallis nonparametric tests. Results: The null hypothesis was accepted. The horizontal incremental placement technique, the oblique incremental technique, and bulk insertion resulted in statistically similar enamel and dentin microleakage scores. Conclusion: Neither the incremental techniques nor the bulk placement technique were capable of eliminating the marginal microleakage in preparations with a high C-factor.

Detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque samples from Brazilian preschool children by polymerase chain reaction

The purposes of this study were to detect S. mutans and S. sobrinus by polymerase chain reaction (PCR) amplification, and to relate their presence to the incidence of dental caries in 42 Brazilian preschool children. Dental plaque samples were collected from the cervical margin of all erupted teeth of 5-6 years old children with primary dentition, using a sterile explorer. Examination of the dmft (decayed, missing, filled teeth) index, performed following the World Health Organization (WHO) caries diagnostic criteria, showed a 2.71 score. Prevalence of S. mutans and S. sobrinus was respectively, of 85.7% and 14.3%; no dental plaque sample was either positive or negative for both bacterial species. Children harboring either S. mutans or S. sobrinus presented the same caries prevalence. PCR showed good discriminative ability for differentiation between these species, and suggested that it is a technique suitable for epidemiological studies on mutans streptococci.

Resin bonding to root canal dentin: Effect of the application of an experimental hydrophobic resin coating after an all-in-one adhesive

Aim: Based on the hypothesis the application of a low-viscosity hydrophobic resin coating improves the bond of all-in-one adhesive, the purpose of the study was to evaluate the bond strength of four adhesive systems to bovine root dentin using the push-out test method. Methods and Materials: The root canals of 32 bovine roots (16 mm) were prepared to a length of 12 mm using a FRC Postec Plus preparation drill. The specimens were allocated into four groups according to the adhesive system used: (Group 1) All-in-one Xeno III; (Group 2) All-in-one Xeno III+ScotchBond Multi-Purpose Plus Adhesive; (Group 3) Simplified Etch & Rinse One Step Plus; and (Group 4) Multi-Bottle Etch & Rinse All-Bond 2. A fiber-reinforced composite retention post was reproduced using an additional silicon impression and fabricated with DuoLink resin cement. The root specimens were treated with the selected adhesive systems, and the resin posts were luted in the canals with DuoLink resin cement. Each root specimen was cross sectioned into four samples (±1.8 mm in thickness), and the post sections were pushed-out to determine the bond strength to dentin. Results: Group 2 (2.9±1.2) was statistically higher than Group 1 (1.1±0.5) and Group 3 (1.1±0.5). Groups 1 and 3 showed no statistically significant difference while Group 4 (2.0±0.7) presented similar values (p>0.05) to Groups 1, 2, and 3 [(one-way analysis of variance (ANOVA)] and Tukey test, α=0.05). Conclusion: The hypothesis was accepted since the application of the additional layer of a low-viscosity bonding resin improved the bond of the all-in-one adhesive. Further studies must be conducted to evaluate the long-term bond.

Bone spreading technique a case report

Bone spreading technique (BST) is a horizontal augmentation with minimal trauma for simultaneous implant placement and an alternative to Summer's osteotome technique both for its clinical use and for the armamentarium. The foremost advantage of the crest dilation technique is a substantially less invasive method; the buccal wall expands after the medullary bone is compressed against the cortical bone. The lateral dilation and compaction of medullary bone improved primary stability. The vital difference is that the BST used in this case report avoided discomfort of the patient, thus eliminating the need for malleting.

Longitudinal bond strength evaluation using the deproteinized dentin technique

This study evaluated bond strength to dentin as a result of storage time for conventional adhesive systems (with or without collagen) that had been deproteinized with 10% sodium hypochlorite (NaOCl). For this study, 72 human molars were sectioned in a mesiodistal axial plane and embedded in acrylic resin; at that point, the vestibular and lingual surfaces were worn down with abrasive paper. Acid etching was performed for 15 seconds (using 37% phosphoric acid) and the specimens were divided into 12 groups (n = 6), depending on the adhesive system used, the dentin treatment performed, and the length of evaluation (24 hours or six months). A resin composite was inserted over the prepared area with the aid of a metal matrix. Following a mechanical shear test, fractured surfaces were analyzed by stereomicroscope and the data were submitted to ANOVA and Tukey's test. It was concluded that the dentin deproteinization treatment with 10% NaOCI improved the bond strength in five of the six groups. The bond strength after 24 hours was significantly higher than the bond strength measured after six months. Of the three adhesive systems tested in this study, DenTASTIC UNO demonstrated the lowest bond strength.

Microhardness of glass ionomer cements indicated for the ART technique according to surface protection treatment and storage time

The aim of this study was to assess the microhardness of 5 glass ionomer cements (GIC) - Vidrion R (V, SS White), Fuji IX (F, GC Corp.), Magic Glass ART (MG, Vigodent), Maxxion R (MR, FGM) and ChemFlex (CF, Dentsply) - in the presence or absence of a surface protection treatment, and after different storage periods. For each GIC, 36 test specimens were made, divided into 3 groups according to the surface protection treatment applied - no protection, varnish or nail varnish. The specimens were stored in distilled water for 24 h, 7 and 30 days and the microhardness tests were performed at these times. The data obtained were submitted to the ANOVA for repeated measures and Tukey tests (α = 5%). The results revealed that the mean microhardness values of the GICs were, in decreasing order, as follows: F > CF = MR > MG > V; that surface protection was significant for MR, at 24 h, without protection (64.2 ± 3.6a), protected with GIC varnish (59.6 ± 3.4b) and protected with nail varnish (62.7 ± 2.8ab); for F, at 7 days, without protection (97.8 ± 3.7ab), protected with varnish (95.9 ± 3.2b) and protected with nail varnish (100.8 ± 3.4a); and at 30 days, for F, without protection (98.8 ± 2.6b), protected with varnish (103.3 ± 4.4a) and protected with nail varnish (101 ± 4.1ab) and, for V, without protection (46 ± 1.3b), protected with varnish (49.6 ± 1.7ab) and protected with nail varnish (51.1 ± 2.6a). The increase in storage time produced an increase in microhardness. It was concluded that the different GICs, surface protection treatments and storage times could alter the microhardness values.

Radiographic study of ossification of the pterygospinous and pterygoalar ligaments by the Hirtz axial technique.

The correct radiographic identification of ossification of the pterygospinous and pterygoalar ligaments plays an important role in surgical procedures for the treatment of trigeminal neuralgia. Most of these procedures are performed through the foramen ovale, a site where these ligaments can be found to be partially or completely ossified. We studied the radiographic features of these ossified ligaments and their location in relation to the foramen ovale by the Hirtz axial technique. For this purpose, 93 dry skulls from the Discipline of Anatomy, São José dos Campos Dental School, UNESP, which presented partial or complete ossification of these ligaments, were radiographed. The pterygospinous ligament was detected on 27.97% of radiographs and was partially ossified in 19.36% of cases and completely ossified in 8.61%. The pterygoalar ligament was present in 62.35% of radiographs, being partially ossified in 49.44% and completely ossified in 12.91%. The pterygospinous ligaments was found to be partially and completely ossified on the same radiograph in 3.23% of cases, whereas the pterygoalar ligament appeared partially and completely ossified on the same radiograph in 6.45%. Furthermore, the pterygospinous ligament was thinner than the pterygoalar ligament and located more medially in relation to the foramen ovale. The pterygoalar ligament formed a large bone bar lateral to the foramen ovale, often obliterating the lumen of the latter. The Hirtz axial technique is an excellent tool for the observation of complete or partial ossification of the pterygospinous and pterygoalar ligaments in surgical procedures for the treatment of trigeminal neuralgia performed through the foramen ovale.

A CAD/CAM flapless surgical technique and immediate prosthesis: A clinical report

Background: This article describes a clinical report with a new system for guided surgical treatment and immediate load prosthesis in the flapless surgical technique. Case report: Based on a computed tomography (CT) of a 64 - year-old edentulous patient, the cross sections were reformatted and used to construct a virtual planning of the implants and a guide template in Dental Slice. Six dental implants were placed in the maxilla and mandible using a Slice Guide System. Following a 30-month in maxilla and 24-month in mandible healing period, the clinical and radiographic evaluation and computed tomography (CT) showed good clinical stability. The Slice Guide System proved satisfactory for the Flapless Surgical Technique in dental implants.

Effects evaluation of remaining resin removal (three modes) on enamel surface after bracket debonding

Introduction: An appropriate selection of instruments is essential to perform a correct debonding technique, by properly removing orthodontic brackets and the remaining resin. Objective: The aim of this study was to evaluate three methods of remaining resin removal on enamel surface after bracket debonding, by means of Scanning Electron Microscopy (SEM). Methods: Eighteen bovine incisors were selected and divided into three groups (A, B and C) of six teeth each. Before bracket bonding, epoxy resin casts were obtained by impression of the teeth with addition silicon, in order to register baseline enamel characteristics and representing the control group. The methods for remaining resin removal were: Group A - gross and medium granulation Soflex discs; Group B - carbide bur in low-speed; Group C - carbide bur in high-speed. Soflex polishing system fine and ultrafine granulation discs were used for Group A, rubber tips for Groups B and C, and polishing paste for all groups. After polishing, impression of teeth were taken and casts were analyzed by means of SEM. The baseline enamel characteristics (Control Group) were compared to the final aspect of enamel to determine the method that generated less enamel abrasion. Results and Conclusion: The remaining resin removal by carbide bur in low-rotation, and enamel polished with rubber tips followed by polishing paste produced the smaller damage to the enamel.

Ligature of external carotid artery as an optional technique in a patient with von Willebrand disease

The von Willebrand disease (vWD) is a hereditary coagulopathy. There is no gender predilection. Clinically characterized by mucocutaneous bleeding, especially nose bleeding, menorrhagia and bleeding after trauma. This article reports a case of a 52-year-old Caucasian male patient with vWD, who presented with extensive bleeding in the tongue after a lacerating injury caused by accidental biting, and describes some clinical, pathological and treatment aspects of vWD. After repeated attempts to suture the wound and replace clotting factors, a decision was made to perform the ligature of the external carotid artery ipsilateral to the injury. There was favorable resolution of the case, with a good aspect of the scar 2 months after ligation. This case reinforces that it is extremely important to make a thorough review of medical history of all patients, searching for possible bleeding disorders or previous family history.

Implant removal by means of an expansion of the alveolar bony crest: Report of a clinical technique

Aim: To describe the adaptation of the Edentulous Ridge Expansion (E.R.E.) technique for implant removal. Material and Methods: The E.R.E. technique for the removal of failed implants is described in detail. A clinical case is also reported. In a patient carrying a full arch removable prosthesis in the upper jaw, sustained by two bars, two out of five implants were found to be fractured. Bucco-lingual partial-thickness flaps were used to access the fractured implants. The implants were subsequently removed applying the E.R.E. technique. Two recipient sites were prepared in the same position, using bone expanders, and two new implants were installed. Results: After 4 months of healing, the implants were integrated and a new bar was fabricated, and the old prosthesis readapted. Conclusion: The ERE technique may be successfully applied for the removal of failed implants, and the immediate or delayed reinstallation of new implants. © 2012 John Wiley & Sons A/S.