The genetics of amelogenesis imperfecta: a review of the literature

A melogenesis imperfecta (AI) is a group of inherited defects of dental enamel formation that show both clinical and genetic heterogeneity. Enamel findings in AI are highly variable, ranging from deficient enamel formation to defects in the mineral and protein content. Enamel formation requires the expression of multiple genes that transcribes matrix proteins and proteinases needed to control the complex process of crystal growth and mineralization. The AI phenotypes depend on the specific gene involved, the location and type of mutation, and the corresponding putative change at the protein level. Different inheritance patterns such as X-linked, autosomal dominant and autosomal recessive types have been reported. Mutations in the amelogenin, enamelin, and kallikrein-4 genes have been demonstrated to result in different types of AI and a number of other genes critical to enamel formation have been identified and proposed as candidates for AI. The aim of this article was to present an evaluation of the literature regarding role of proteins and proteinases important to enamel formation and mutation associated with AI.     

Human peri-implant bone response to turned and oxidized titanium implants inserted and retrieved after 2 months

PURPOSE: The aim of this study was to evaluate the influence of oxidized surface on bone-to-implant contact percentage (BIC%) as well as the bone density within the threads area (BD%) in human bone after 2 months of unloaded healing. MATERIALS: Seven subjects (mean age 45.57 +/- 10.45 years) received 2 micro-implants each during conventional implant surgery in the posterior maxilla. The implants that presented turned and oxidized surfaces served as control and test, respectively. After the healing period, the implants and the surrounding tissue were removed and prepared for ground sectioning and analysis. RESULTS: Two turned implants were found to be clinically unstable at the time of retrieval. Histometric evaluation showed that the mean of BIC% was 17.40 +/- 14.16% and 32.19 +/- 15.68% to turned and oxidized surfaces, respectively. The BD% was 22.13 +/- 19.06% for turned surface and 50.40 +/- 18.35% for oxidized surface. CONCLUSION: The histologic data from this preliminary study suggest that the oxidized micro-implants surface presented better mean values of BIC% and BD% than turned micro-implants after a short healing time.     

Tooth loss and subluxation in the primary dentition: a twelve-year follow-up case report

The case of a five-year-old child is reported, who suffered dento-alveolar injury including subluxation of the right upper lateral incisor and avulsion of the upper central incisors and left upper lateral incisor and laceration in the mucosa. The case was followed for 12 years until complete root formation and alignment of the anterior permanent teeth.     

Peripheral osteoma of the mandible: case report and review of the literature.

BACKGROUND: Osteoma is a benign often asymptomatic neoplasm, consisting of well-differentiated mature bone. This paper reports a case of peripheral osteoma located in the anterior mandibular region and provides a review of the literature about this lesion in the jaws. PATIENT AND METHODS: A 43-year-old white woman presented with a swelling in the left mandible of 7 years duration. The English literature was reviewed over the past 76 years and data about location, histopathology and number of the peripheral osteomas, sex, and age of the patients were evaluated. RESULTS: Data analysis showed 69 well-documented cases of peripheral osteoma. Peripheral osteomas are more frequent in the mandible than the maxilla and the cancellous type was most frequent; males and females are equally affected in the mandible; the age range was 9-85 years. CONCLUSION: The peripheral type of osteoma is most common in the lower jaws, occurs at the surface of the cortical bone and is sessile or pedicled.     

Marginal leakage of polyacid-modified composite resin restorations in primary molars: an in vitro study

The purpose of this in vitro study was to compare the marginal leakage in primary molars restored with 2 polyacid-modified composite resins (Dyract AP - Dentsply and F2000 - 3M) and a composite resin (Filtek Z250 - 3M) as control. First and second primary molars were used for preparation of cavities on the proximal surfaces, with extension of the gingival margin to the cementoenamel junction. Restorations were accomplished after total etching and application of the respective adhesive system, and were divided into groups according to the restorative system and the number of adhesive layers used. The teeth were stored in distilled water for 7 days, followed by thermocycling with 500 cycles at 5oC - 55oC, with one minute in each bath. Thereafter, teeth were prepared for immersion in 0.5% methylene blue solution for four hours. The teeth were sectioned in mesiodistal direction for assessment of dye penetration. According to the results of the Kruskal-Wallis test, the three restorative materials employed did not completely avoid marginal leakage at the gingival margin of primary molars. The marginal leakage of PMCR F2000 (4.06 and 3.95) displayed to be higher than the marginal leakage observed for the materials Dyract AP (2.7 and 2.55) and Filtek Z250 (2.25 and 2.43). The number of adhesive layers did not influence the degree of leakage of the three materials.     

Analysis of the condyle/fossa relationship before and after prosthetic rehabilitation with maxillary complete denture and mandibular removable partial denture

STATEMENT OF PROBLEM: The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue. PURPOSE: This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs. MATERIAL AND METHODS: The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05). RESULTS: Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70). CONCLUSION: Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.     

In vitro assessment of the antimicrobial action and the mechanical ability of chlorhexidine gel as an endodontic irrigant

The objective of this study was to assess the chlorhexidine gluconate gel as an endodontic irrigant. First the ability of chlorhexidine gel to disinfect root canals contaminated in vitro with Enterococcus faecalis was investigated. A scanning electron microscope was also used to evaluate its cleansing ability compared with endodontic irrigants commonly used, such as sodium hypochlorite and chlorhexidine gluconate liquid. The results indicated that the chlorhexidine gel produced a cleaner root canal surface and had an antimicrobial ability comparable with that obtained with the other solutions tested. It was concluded that chlorhexidine gluconate in gel form has potential for use as an endodontic irrigant.     

Prevalence of 6 putative periodontal pathogens in subgingival plaque samples from Romanian adult periodontitis patients

Abstract The aim of the present study was to determine by standard cultivation procedures the detection frequencies of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum. Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Capnocytophaga species as well as various enteric rods in subgingival plaque samples form Romanian adult periodontitis patients. DNA probe analysis (Affirm^TM DP Microbial Identification Test) was also used, parallel to cultivation, to identify P. gingivalis. A. actinomycetemcomitans, and B. for- sythus, in deep (≥6 mm) and intermediate (4–5 mm) pockets in some of the subjects investigated. Paper points were used to sample 86 deep pockets in 36 patients and 27 intermediate pockets in 9 of the 36 patients. The x² test was used to test for significance of differences between results obtained by cultivation and DMA analysis in both intermediate and deep pockets. P. gingivalis was recovered in a high percentage of the patients (75,8%) and sites (63.6%) examined, followed by P. intermedia, F. nucleatum, and A. actinomycetemcomitans, respectively. Capnocytophaga species were present in almost all subjects. Enteric rods were recovered in 61.1% of the patients and 55.8% of the sites. Except for this high prevalence of enteric rods, the present group of patients had the periodontal species monitored in %s similar to those commonly perceived in the West. The Affirm M DP Test and cultivation showed poor correlation in detecting P. gingivalis. A. actinomycetemcomitans, and B. forsythus. The cultivation prevalence of P. gingivalis and P. intermedia in deep pockets was similar to their prevalence in intermediate ones. Overall, the prevalence of the periodontal pathogens investigated in the present Romanian periodontitis patients is similar to what has been revealed in matching Norwegian and other Western periodontitis patient populations. The high prevalence of enteric rods in the Romanian patients may have been an artifact resulting from prolonged transport of the samples in VMGA III.     

PATTERN OF DISOCCLUSION IN PATIENTS WITH COMPLETE CLEFT LIP AND PALATE

Objective:

to analyze the pattern of disocclusion during excursive mandibular movements and presence or absence of occlusal interferences and occlusal pathologies (gingival recession and abfraction).

Method:

examination of 120 individuals divided into two groups, as follows: Group 1-90 patients with complete cleft lip and palate (study group), subdivided into 30 patients with complete left unilateral cleft lip and palate, 30 patients with complete right unilateral cleft lip and palate and 30 patients with complete bilateral cleft lip and palate; Group 2-30 individuals without clefts (control group).

Results:

58.8% of patients in Group 1 presented unilateral or bilateral canine guidance, 26.6% presented unilateral or bilateral group function and 54.4% presented lateral movements through the posterior teeth. Regarding protrusive movements, 80% presented anterior guidance and 20% presented posterior guidance. In Group 2, 69.6% of individuals presented unilateral or bilateral canine guidance, 43.2% presented unilateral or bilateral group function and only 13.3% presented lateral movements through the posterior teeth; 3.4% presented protrusion through the posterior teeth.

Conclusions:

there was no difference in the pattern of disocclusion between subgroups of patients with clefts. Group 2 presented predominance of bilateral group function, whereas Group 1 presented a higher prevalence of posterior guidance during lateral movements. Protrusion occurred primarily through anterior guidance in Group 2 and through the posterior teeth in Group 1. There was high prevalence of occlusal interferences at the molar area for both groups, yet with no correlation with occlusal pathologies (recession and abfraction).     

Evaluation of the castability of a Co-Cr-Mo-W alloy varying the investing technique

The purpose of this study was to compare the castability of Co-Cr-Mo-W (Remanium 2000), Ni-Cr (Durabond) and Co-Cr-Mo (Vera PDI) alloys invested with either conventional (phosphate- and silica-based) or mixed investing techniques. A 10 X 10 mm square-shaped nylon net containing 100 open squares served as a template for construction of wax patterns, which were invested with phosphate-based investment (Termocast), silica-based investment (Refrafil) and mixed investing technique (2-mm layer phosphate investment plus filling with silica investment). Forty-five cast specimens (5 per experimental condition) were obtained and sandblasted with aluminum oxide. The number of completely reproduced cast segments was counted to obtain a percentage designated "castability value", which indicated the accuracy of the alloy to reproduce mold details. Statistical analysis using two-way ANOVA and Tukey's test showed that, comparing the alloys, Remanium 2000 had statistically similar castability (p>0.05) to Vera PDI and lower than Durabond (p<0.05). Considering the mixed technique results, Remanium 2000 yielded lower castability value (p<0.05) than Durabond and Vera PDI alloys, which showed similar results to each other (p>0.05). In conclusion, the castability of the Co-Cr-Mo-W alloy (Remanium 2000) was comparable to that of the Co-Cr alloy (Vera PDI) and worse than that of the Ni-Cr alloy (Durabond). Except for Remanium 2000, the mixed investing technique considerably improved the accuracy of the alloys to reproduce cast details, compared to the phosphate-based investment. The mixed investing technique appears as a viable alternative to improve castability of base metal alloys without decreasing the surface quality of the metallic pieces.