Trans-sinusal maxillary distraction for correction of midfacial hypoplasia: long-term clinical results

Maxillary distraction osteogenesis is indicated in severe angle class III malocclusions, and severe maxillary hypoplasia among some cleft patients and other craniofacial deformities. Twenty patients, aged 8-48 years (mean 17.8+/-10.5 SD) with maxillary and midfacial hypoplasia were treated. The follow-up period was 13-65 months (mean 35+/-16.3 SD). A trans-sinusal maxillary distractor was placed intraorally at each side of the maxilla. The distraction vector was predicted using specialist software, and was transferred to the patients using stereolithographic models and individual templates. A (high) Le Fort I type osteotomy was performed. The amount of activation varied from 8 to 17.5 mm (mean 13.1+/-2.9 SD). Soft and hard tissue formation resulted in complete healing across the distraction gaps. The distractors are almost completely submerged, and can be left in place as long as necessary to avoid relapse. Wit's appraisal was used to measure the stability of the long-term distraction results. Results up to 5 years after distraction showed considerable maxillary advancement with long-term stability. Ongoing growth of the facial skeleton must be considered when distraction osteogenesis is chosen in growing patients.     

Effects of systemic fluoride and in vitro fluoride treatment on enamel crystals

Systemically administered fluoride at a concentration of 75 ppm increases the surface roughness of developing enamel crystals in rats, which may be significant in advancing our understanding of the biological mechanism of fluorosis. Thus, the aim of this study was to investigate whether the increased surface roughness may be a result of surface restructuring by the direct action of fluoride at the crystal surface. We examined the fluoride dose-dependent roughening of enamel crystal surfaces in vivo, in the rat, and whether this roughening could be mimicked by the in vitro treatment of rat enamel crystals with neutral pH fluoride solutions. Our results showed that enamel crystal surface roughness increased after treatment with increasing fluoride ion concentrations, whether applied in vitro or administered systemically. This suggests a mechanism, alongside others, for the increased surface roughness of crystals in fluorotic enamel.     

Endosseous cylinder implants in severely atrophic mandibles.

A retrospective study was completed to assess the success rate of endosseous cylinder implants placed in mandibles that were 10 mm or less in maximum anterior height as measured from lateral cephalometric radiographs. Only implants that were located anteriorly between the mental foramina and loaded prosthetically for a minimum of 1 year were studied. Twenty-eight patients with a total of 130 Nobelpharma implants (forty-six 7 mm and eighty-four 10 mm) were included. The fixtures were evaluated following standard clinical criteria for success established for implants of this type. A total of 8 (two 7 mm and six 10 mm) of 130 implants failed, yielding an overall success rate of 94%. Major complications encountered included a complete mandibular fracture, a partial mandibular fracture, and a temporary bilateral mental nerve hypoesthesia.     

Amalgam and composite restorations: reasons for placement and replacement

A survey, in order to ascertain the reasons for placement and replacement of amalgam and composite restorations was made with the consent of the Italian Academy of Conservative Dentistry. 62 dentists answered the questionnaire, analysing their daily restorative work for two weeks: a total of 2,960 restorations were scored. The results show a prevalence of the primary caries over the replacements, and a prevalence of the secondary caries over the remaining reasons for replacement. Both data possibly mean the need for a more preventive approach to dental caries in Italy, even if the results fit fairly well into the values of the international research.     

Quality of marginal adaptation evaluation of posterior composites in clinical trials

The evaluation of margins of restorations in clinical trials relies on the subjective assessment of evaluators, with no instrument having been developed, let alone validated, to assist in the process. The purpose of the present study was to assess the quality of evaluations of marginal adaptation by analyzing the distribution of marginal steps rated according to clinical criteria. Replicas of 435 restorations, the marginal qualities of which had been evaluated according to modified USPHS criteria, were randomly selected from the Occlusin multi-center clinical trial program. The marginal step height in the most deteriorated area of each restoration was measured by means of a digital step-height instrument. An overlap between the steps in the restorations with A (Alfa; replacement unnecessary) and B (Bravo; replacement questionable) ratings was found to be in the range of 101 microm to 321 microm. When the steps with a height greater or less than one standard deviation of the mean were excluded, the overlap was reduced to a range of 168 micro m to 173 microm. This finding indicates a marginal height boundary between A and B ratings for marginal adaptation of 170 +/- 3 microm.