[Conservative and simple rehabilitation to compensate posterior open bite: partial bonded restauration]. / Des solutions simples et conservatrices pour la compensation des infraclusions postérieures : les restaurations partielles collées.

Posterior open bite is a malocclusion characterized by the absence of vertical contacts between the occlusal surfaces of the posterior teeth of the opposing arches. It can be uni- or bilateral and involve one tooth or more. Several aetiologies of these posterior open bite have been described, including pathological eruptions, dento-maxillary dysmorphosis and temporo-mandibular dysfunctions. When considering a correction or compensation, there are several therapeutic options (orthodontic and/or surgical and/or prosthetic). Recent developments in adhesive dentistry (bonding biomaterials, ceramics and composites) have made possible the development of more conservative approach for restorative and prosthetic treatments. In order to understand the possible use of these restorations and the help it can provide in our treatment plan, we have selected three original clinical situations. Each one illustrated a posterior open bite aetiology and explained the rehabilitation strategies chosen (process of decision making and realization). Partial bonded restorations (direct composites, overlays, tabletops, veenerlays) can be considered to compensate open bite, in case of impossibility, failure or as a complement of orthodontic treatments. Additive equilibration is not described in the literature for the compensation of posterior open bite, despite the many functional advantages along a simple and conservative technique.

WITHDRAWN: Root canal posts for the restoration of root filled teeth.

BACKGROUND: The foundation for the reconstruction of endodontically-treated teeth can be provided by a metal or a non-metal post and core system but no guidelines exist for choosing one or the other in particular clinical cases. OBJECTIVES: To assess the effectiveness of different post and core systems for the restoration of endodontically-treated teeth. The primary objective of this review was to compare the clinical failure rates of the different types of posts. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2005, Issue 3), MEDLINE (from 1966 to September 2005), Scopus (from January 1985 to December 2004) and EMBASE (until December 2004). We looked through reference lists of articles and dental conference proceedings. We contacted researchers in the field and manufacturers. SELECTION CRITERIA: Randomised or quasi-randomised clinical trials (RCTs) comparing failures on endodontically-treated permanent teeth with different types of post. The outcomes were loss of retention, post fracture and root fracture. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the quality of trials and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Two trials involving 317 participants were included but only one of them, involving 200 participants, compared metal to non-metal posts. The other answered to the secondary objective. The risk of failure was greater with metal-cast posts (9/98) compared to carbon fibre posts (0/97) (risk ratio (RR) = 0.05 (95% confidence interval (CI) 0.00 to 0.90)) but the study was at high risk of bias. Thus fewer failures occurred when using non-metal posts but the evidence is unreliable. AUTHORS' CONCLUSIONS: Our systematic review could not specify which type of post and core system should be used when two or three dentine walls remain. More RCTs are needed to confirm whether fibre-reinforced post and core systems are superior and to clarify the influence of the remaining tooth structure on the treatment outcome of the different post and core systems available. Well-defined inclusion criteria focusing on the number of dentine walls (two or three) should be used.

Scanning electron microscopy analysis of experimental bone hacking trauma of the mandible.

The authors report on a macroscopic and microscopic study of human mandible bone lesions achieved by a single-blade knife and a hatchet. The aim of this work was to complete the previous data (scanning electron microscopy analysis of bone lesions made by a single-blade knife and a hatchet, on human femurs) and to compare the lesions of the femur with those of the mandible. The results indicate that the mandible is a more fragile bone, but the features observed on the mandible are quite similar to those previously observed on the femur. This work spells out the main scanning electron microscopy characteristics of sharp (bone cutting) and blunt (exerting a pressure on the bone) mechanisms on human bone. Weapon characteristics serve to explain all of these features.

Surface finish produced on three resin composites by new polishing systems.

This study evaluated the surface finish of three direct resin composites polished with three different systems. Disk-shaped specimens (n=16 per material; phi=8.0 mm x h=2.0 mm) were formed in a stainless steel mold by packing uncured material, either a hybrid composite (Z250, 3M ESPE) or two micro-hybrid composites (Point 4, Kerr; Esthet-X, Dentsply), and light-cured from the top and the bottom surfaces with a light-emitting diode (LED) curing unit (NRG, Dentsply). After storing the specimens in deionized water at 37 degrees C for seven days, one side of each specimen was finished through 1200-grit SiC abrasive (Buehler). Five specimens of each resin composite were randomly assigned to one of the three polishing systems (Identoflex, Kerr; Pogo, Dentsply; Sof-Lex, 3M ESPE). Manufacturers' instructions were followed during the polishing procedures. The average surface roughness (Ra) was determined by generating tracings across the polished surface of each disk using a scanning profilometer (Surfanalyzer System 5000, Federal Products Co). The results were analyzed by Kruskal-Wallis and Mann and Whitney tests (p < or = 0.05). The smoothest surfaces were produced with the celluloid strip (control group) on all the resin composites tested. The aluminum oxide disks (Sof-Lex) produced a statistically equivalent surface finish (Ra) on the three resin composites. The lowest mean roughness values were recorded with diamond micropolisher disks (PoGo) on the hybrid composite (Z250). Overall, the two new polishing systems, Identoflex and PoGo, created a comparable surface finish to that produced by the Sof-Lex system on all three resin composites.

Scanning electron microscopy analysis of experimental bone hacking trauma.

The authors report on their macro- and microscopy study of bone lesions made by a sharp force instrument (a single blade knife), and a sharp-blunt instrument classified as a chopping weapon (a hatchet). The aim of this work was to attempt to identify the instrument by analyzing the general class characteristics of the cuts. Each weapon was used on human bones. The results indicate that macroscopic analysis is more problematic. The microscopic analysis assessed that characteristics examined were effective in distinguishing sharp from sharp-blunt injury to the bone. The microscope facilitates analysis unachievable with macroscopic methods, some three-dimensional characteristics not visible to the naked eye being clearly defined with its use. Emphasis has been placed on the value of SEM as an anthropologist's tool in bone lesion injuries.

Microleakage of a pit-and-fissure sealant: effect of air-abrasion compared with classical enamel preparations.

PURPOSE: The aim of this study was to assess the microleakage of a pit-and-fissure sealant after classical enamel preparations (prophylaxis followed by acid etching alone and mechanical widening with bur) and after air abrasion. MATERIALS AND METHODS: Ninety noncarious freshly extracted third molars were randomly assigned to three groups of 30. In each group, the mesial halves of the fissures were treated with air abrasion and conditioned with acid etching for 15 s. In group 1, the distal halves were treated with acid etching alone. In group 2, the distal halves of the fissures were widened mechanically with a bur and etched for 15 s. In group 3, the distal halves were prepared with air abrasion alone. Then the sealant (Clinpro) was applied on the occlusal fissures of all teeth, according to the manufacturer's recommendations. The teeth were thermocycled and the samples placed in a 1% methylene blue dye solution. The teeth showing microleakage and the means of infiltration were assessed with an image analysis system. RESULTS: The microleakage of sealants prepared with air abrasion alone displayed significantly greater microleakage (80%) (p < 0.0001) than the ones placed after prophylaxis and etching (13.33%), bur and etching (20%), or air abrasion and etching (22.2%). The samples prepared with air abrasion alone also showed the highest mean microleakage (1.14 +/- 1.4 mm) when compared to samples receiving prophylaxis and acid etching (0.12 +/- 0.41), bur and acid etching (0.08 +/- 0.26), or air abrasion and acid etching (0.09 +/- 0.4) (p < 0.05). No significant difference was noted between the three types of enamel preparation when etching was performed. CONCLUSION: Air-abrasion treatment does not eliminate the need for etching the enamel surface before applying the sealant.

A survey of disinfection of irreversible hydrocolloid and silicone impressions in European Union dental schools: epidemiologic study.

PURPOSE: The objective of this cross-sectional study was to describe corresponding procedures for irreversible hydrocolloid and silicone impressions taught and used in European Union dental schools. MATERIALS AND METHODS: A self-administered questionnaire requesting information about rinsing and disinfection methods was sent to each of the 373 heads of prosthodontic, pedodontic, and orthodontic departments in the 131 European Union dental schools. Response rate was 94%. Statistical analysis included chi-square or Fisher exact tests, and ANOVA or Kruskall-Wallis tests. RESULTS: Of the responding departments, 92% systematically rinsed their impressions. Fifteen percent of the departments, mostly orthodontics, never disinfected irreversible hydrocolloid impressions, and 11% never disinfected silicone impressions. The immersion method was used by 65% for irreversible hydrocolloid impressions (73% for silicone), with a disinfection time of 10.3 +/- 6.3 minutes (11.8 +/- 7.4 for silicone). The disinfected impressions were not rinsed by 16% for irreversible hydrocolloid and 14% for silicone. Most departments used brand-name products. CONCLUSION: The same disinfection procedure for both irreversible hydrocolloid and silicone impressions was used by 78% of departments. There was great diversity, however, between departments in the procedure used for each impression material.

Comparative study of microleakage of a pit and fissure sealant placed after preparation by Er:YAG laser in permanent molars.

PURPOSE: The aim of this study was to assess the microleakage of a pit and fissure sealant on enamel treated with a laser, with and without etching. METHODS: Sixty non-carious extracted molars were randomly assigned to 2 groups. For both groups, in the mesial halves, the fissures were widened mechanically with a bur and etched for 15 seconds. In group 1, the distal half was prepared with a laser alone; in group 2, a laser was followed by etching. Then the sealant was applied on all teeth. RESULTS: Laser alone showed the highest number of specimens with microleakage (63%) (P < .02) and the highest mean of microleakage (0.76 mm vs 0.12 mm, 0.17 mm, and 0.18 mm; P < .01). CONCLUSIONS: No significant difference was noted between the 2 types of enamel preparation when etching was performed. Laser irradiation did not eliminate the need for etching the enamel surface before applying the sealant.

Orofacial trauma and rugby in France: epidemiological survey.

A stratified epidemiological survey was carried out among the best French rugby players to assess the prevalence of trauma to the lower or middle part of the face (TLMPF) and the frequency at which the mouthguards (MGs) were worn. The 1140 randomized players (elite 1, elite 2 and national 1 clubs) filled in the same form anonymously. The variables were first subjected to univariate analysis (Chi-square, anova). Secondly, they were included in a multivariate model (logistic regression). Some 29.57% of players had already been affected by a TLMPF. The risk increased for the oldest forward players. It also increased with the number of yearly competitions and number of hours of weekly training. Some 64.3% of players used a MG. The frequency at which it was worn increased with the number of yearly competitions, for those who had experinced a previous trauma and for the pack players who had been playing for a long time.

Age estimation from teeth in children and adolescents.

The aim of this cross-sectional study was to evaluate the dental formulas according to age because of possible changes during the last decades. From these dental formulas, the median age of emergence for the permanent teeth was deduced. The study population corresponded to the 1 to 15 year-old children who had consulted either a pediatric dentist or orthodontist in the city of Nice (France). Data were collected from the 5,848 patients' charts that included an orthopantomography. This permitted the observation of emerged teeth and agenesis. Bar charts were used to indicate the dental formula according to age. There was no significant difference in the emergence pattern of both controlateral maxillary and mandibular teeth. Only the anterior tooth emergence significantly differed according to the maxillary. The lower central incisor was the lone tooth with a median age earlier than others; the remaining teeth had an age equivalent to those of previously estimates.