In vitro evaluation of the precision of working casts for implant-supported restoration with multiple abutments

Objective: The purpose of this study was to compare the accuracy of two working cast fabrication techniques using strain-gauge analysis. Methods: Two working cast fabrication methods were evaluated. Based on a master model, 20 working casts were fabricated by means of an indirect impression technique using polyether after splinting the square transfer copings with acrylic resin. Specimens were assigned to 2 groups (n=10): Group A (GA): type IV dental stone was poured around the abutment analogs in the conventional way; Group B (GB), the dental stone was poured in two stages. Spacers were used over the abutment analogs (rubber tubes) and type IV dental stone was poured around the abutment analogs in the conventional way. After the stone had hardened completely, the spacers were removed and more stone was inserted in the spaces created. Six strain-gauges (Excel Ltd.), positioned in a cast bar, which was dimensionally accurate (perfect fit) to the master model, recorded the microstrains generated by each specimen. Data were analyzed statistically by the variance analysis (ANOVA) and Tukey's test (α= 5%). Results: The microstrain values (με) were (mean±SD): GA: 263.7±109.07με, and GB: 193.73±78.83με. Conclusion: There was no statistical difference between the two methods studied.

Dental age in patients with Down syndrome

The aim of this research was to evaluate dental age in 102 patients with Down Syndrome, using panoramic radiographs. A software program developed by the Discipline of Radiology, School of Dentistry of São José dos Campos, São Paulo State University (UNESP), was used. A table of mineralization chronology of permanent teeth among Brazilians conceived by Nicodemo, Moraes and Medici Filho was used within the software. Statistical analysis of the results showed that 70.91% of the males land 61.21% of the females presented advanced dental age. Only 32.09% of the males and 39.79% of the females presented delayed dental age. Regarding the differences between the dental and chronological ages, two thirds of the males and females presented dental age with differences of up to 12 months, which means that they can be considered to be within normal standards, whereas only 18.87% of the males and 10.21% of the females presented dental age outside normal standards, with differences of over 24 months. In conclusion, the majority of the patients with Down Syndrome were considered to be within the normal standards of mineralization chronology.

Prevalence of dental trauma in patients with cerebral palsy

This study presents the findings of a record review that evaluated the prevalence of dental trauma in patients with cerebral palsy and evaluated its possible relationship with age, type of palsy, and epilepsy. The dental records of 2,200 patients with special needs admitted to the special care clinic of the School of Dentistry of Araçatuba/UNESP, Brazil, between 1998 and 2003 were reviewed. Of the records that were analyzed, 500 patients who had cerebral palsy were selected for this study. Information regarding age, gender, type of palsy and dental trauma was collected and statistically analyzed. It was observed that 10.6% of the subjects (n = 53) had sustained dental trauma. The number of traumatized teeth was 84. Enamel or enamel/dentin fractures were the most frequent types of traumatic injury (84.9%). The permanent maxillary central incisors were the most commonly affected teeth (50%). The frequency of traumatic injuries showed no significant correlation (p>.05) with the type of cerebral palsy or gender and they were more frequent in subjects between the ages of 0 and 12 years. Having epilepsy was not a statistically significant risk factor (p>.05) for dental trauma. © 2008 Special Care Dentistry.

Prevention of dental trauma during childhood: An overview

The aim of the present study was to evaluate the prevention of dental trauma in children aged 0 to 3 years, as it is studied in the literature. Since these traumatic injuries can cause damage and complications to the deciduous teeth, and even to the permanent teeth, the development of actions to reduce their occurrence is necessary because these injuries represent a considerable problem in dentistry. Although prevention is difficult in this age group, efforts should be directed at education, especially the development of educational programs involving qualified professional directly engaged in the routine of traumatic dental injuries. The actions to be adopted should be based on the understanding of etiological factors, on the different patterns of the mechanism of injury, and on the characteristics of each community. © 2009 Bentham Science Publishers Ltd.

Influence of the ICDAS e-learning program for occlusal caries detection on dental students

The aim of this study was to evaluate the influence of ICDAS training in a group of dental students for occlusal caries detection in permanent teeth. Premolars and molars (N=104) with occlusal surfaces varying from ICDAS scores 0 to 6 were cleaned, one occlusal site per tooth was selected, and a photograph taken to identify the site. Eight senior dental students examined the teeth twice with a one-week interval between examinations during each of two phases: before and after the ICDAS e-learning program. Teeth were histologically assessed for caries extension. Intraclass correlation coefficients for intra- and interexaminer repeatability were high, both before (0.75 and 0.72, respectively) and after e-learning (0.82 and 0.78, respectively). The ICDAS scores decreased significantly from before to after e-learning (p=0.0001). Correlation between ICDAS scores and histology scores was moderate (0.57 before e-learning and 0.61 after). Although the ROC curve shows an improvement in the use of the ICDAS scoring after e-learning, the difference was not significant (p=0.10). Specificity of the ICDAS scores significantly improved after e-learning (77 percent vs. 36 percent), and sensitivity was reduced slightly after e-learning (87 percent vs. 92 percent). The ICDAS e-learning program improved the performance of the diagnostic skills of the investigated students for the detection of occlusal caries lesions.

Response of human dental pulp to calcium hydroxide paste preceded by a corticosteroid/antibiotic dressing agent

Aim: To evaluate the treatment with corticosteroid/antibiotic dressing in pulpotomy with calcium hydroxide. Methods: Forty-six premolars were pulpotomized and randomly assigned into 3 groups. In Group I pulpal wound was directly capped with calcium hydroxide, and Group II and Group III received corticosteroid/antibiotic dressing for 10 min or 48 h, respectively, before pulp capping. Teeth were processed for histological analysis after 7, 30 or 60 days to determine inflammatory cell response, tissue disorganization, dentin bridge formation and presence of bacteria. Attributed scores were analyzed by Kruskal-Wallis and Mann-Whitney tests (α=0.05). Results: On the 7th day, all groups exhibited dilated and congested blood vessels in the tissue adjacent to pulpal wound. The inflammatory cell response was significantly greater in Group III (p<0.05). On the 30th day, in all groups, a thin dentin matrix layer was deposited adjacent to the pulpal wound and a continuous odontoblast-like cell layer underlying the dentin matrix was observed. On the 60th day, all groups presented a thick hard barrier characterized by an outer zone of dystrophic calcification and an inner zone of tubular dentin matrix underlined by a defined odontoblast-like cell layer. Conclusions: Within the limitations of present study, considering that the treatment was performed in healthy teeth, it may be concluded that the use of a corticosteroid/antibiotic dressing before remaining tissue protection with calcium hydroxide had no influence on pulp tissue healing.

Developmental Disturbance of an Unerupted permanent incisor due to trauma to its predecessor

Developmental disturbances of permanent teeth can result from trauma to primary teeth because of the proximity of the root of the primary teeth to their permanent successors. We describe the case of a 14-month-old boy who was referred to the baby clinic of the School of Dentistry, Universidad Estadual Paulista, Araçatuba, Brazil, after sustaining a severe trauma that led to intrusion of the right primary central incisor. Radiographic examination 4 years after the trauma showed a developing morphological change in the germ of the permanent successor. On eruption of the permanent central incisor, a crown malformation along with enamel hypoplasia was observed. We concludethat radiographic follow-up is indicated after trauma to monitor possible sequelae in the permanent successors even before their eruption. © 2011 Canadian Dental Association.

Prevalence of chewing side preference in the deciduous, mixed and permanent dentitions

Aim: This study evaluated the prevalence of the chewing side preference (CSP) in the deciduous, mixed and permanent dentitions. Materials and methods: Three-hundred subjects were divided in three groups (n = 100): Group 1 - children with deciduous dentition; group 2-children with mixed dentition; group 3 - subjects with permanent dentition. The CSP was determined using a direct method (visual observation) developed by McDonnell et al. (2004). Descriptive statistic was used to observe the prevalence of CSP. The Pearson's Chi-square was used to investigate signicant associations between gender, presence of CSP and preferred side (right/left). Results and conclusion: Eighty-seven percent of group 1 had a CSP. Eighty-two percent of group 2 had a CSP. Seventy-six percent of group 3 had a CSP. There was no statistically significant association between presence of CSP and gender in all groups. There was no statistically significant association between preferred side (right/left) and gender in all groups. Clinical significance: There is a higher prevalence of subjects in deciduous, mixed and permanent dentition that presented chewing side preference. The early diagnosis of the presence of chewing side preference can prevent the unilateral chewing pattern with prophylactic therapy applied to the first teeth (deciduous).

Evaluation of transverse changes in the dental arches according to growth pattern: a longitudinal study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The challenges of treating a fused tooth

This paper describes and discusses the multidisciplinary treatment involving a permanent maxillary lateral incisor fused to a supernumerary tooth, both presenting pulp necrosis and periapical lesion. A 15-year-old male patient sought treatment complaining of pain, swelling and mobility on the maxillary right lateral incisor. After clinical and radiographic examination, root canal preparation was performed according to the crown-down technique and a calcium hydroxide dressing was placed for 15 days. The patient returned and the definitive endodontic filling was done with thermomechanical compaction of gutta-percha and sealer. After 18 months, clinical and radiographic examinations were carried out and no pain or swelling was reported. Two years after endodontic treatment, the patient returned for periodontal and cosmetic treatments. Nine months later, a cone-beam computed tomography (CBCT) revealed that the previously detected periodontal defect and periapical lesion were persistent. Apical endodontic surgery was indicated. The supernumerary tooth was removed, the communicating distal surface was filled and the surgical site received bioactive glass and demineralized bovine organic bone. The pathological tissue was submitted to histopathological examination and the diagnosis was periapical cyst. One year after the apical endodontic surgery, CBCT showed bone formation at maxillary lateral incisor apical area. Two years after the surgery, the restoration was replaced due to aesthetic reasons and periapical radiograph showed success after 5 years of treatment. A correct diagnosis and establishment of an adequate treatment plan resulted in a successful management of the case.

Apexification with white MTA in an immature permanent tooth with dens invaginatus

Dens invaginatus, also known as dens in dente, is a developmental dental anomaly resulting in an invagination of the enamel organ into the dental papilla. These cases present technical difficulties to the root canal treatment. Apexification using an apical plug of mineral trioxide aggregate (MTA) has been indicated as an alternative to long-term intracanal use of calcium hydroxide in immature permanent teeth. It is considered as a simple and rapid technique. This paper reports a case of Oehlers' Type 1 dens invaginatus in an immature permanent maxillary right lateral incisor, which presented pulp necrosis secondary to dental trauma and was treated by apexification with white MTA apical plugging followed by conventional root canal therapy. The operative procedures are described and the technique is discussed. The physical and biological properties of MTA, associated with appropriate instrumentation and obturation techniques, make this material an excellent option in the endodontic therapy of immature permanent teeth with dens invaginatus.

Compressive strength of dental composites photo-activated with different light tips

The aim of this study was to evaluate the compressive strength of microhybrid (Filtek™ Z250) and nanofilled (Filtek™ Supreme XT) composite resins photo-activated with two different light guide tips, fiber optic and polymer, coupled with one LED. The power density was 653 mW cm -2 when using the fiber optic light tip and 596 mW cm-2 with the polymer. After storage in distilled water at 37 ± 2 °C for seven days, the samples were subjected to mechanical testing of compressive strength in an EMIC universal mechanical testing machine with a load cell of 5 kN and speed of 0.5 mm min-1. The statistical analysis was performed using ANOVA with a confidence interval of 95% and Tamhane's test. The results showed that the mean values of compressive strength were not influenced by the different light tips (p > 0.05). However, a statistical difference was observed (p < 0.001) between the microhybrid composite resin photo-activated with the fiber optic light tip and the nanofilled composite resin. Based on these results, it can be concluded that microhybrid composite resin photo-activated with the fiber optic light tip showed better results than nanofilled, regardless of the tip used, and the type of the light tip did not influence the compressive strength of either composite. Thus, the presented results suggest that both the fiber optic and polymer light guide tips provide adequate compressive strength to be used to make restorations. However, the fiber optic light tip associated with microhybrid composite resin may be an interesting option for restorations mainly in posterior teeth. © 2013 Astro Ltd.

Dental caries experience and Molar-Incisor Hypomineralization

Objective. This cross-sectional study assessed the prevalence and severity of the enamel defects, known as Molar-Incisor Hypomineralization (MIH) and its relationship to dental caries. Materials and methods. A sample of 1157 schoolchildren (population based), aged 6-12 years, of the Araraquara city-Brazil, was evaluated according to the European Academy of Paediatric Dentistry (EAPD) criteria by two trained examiners. The dental impact caused by MIH was evaluated with the Decayed, Missing and Filled Teeth (DMFT) index (WHO). Data were analyzed using ANOVA and Chi-square tests (p < 0.05). The socioeconomic status was collected using a questionnaire answered by parents. Results. The prevalence of MIH was 12.3%. Mild impairment was the most frequent diagnosis. DMFT of children with MIH was 0.89 (±1.18), which are higher than those of the unaffected group (0.43 ± 1.01). An association was found between dental caries only in the permanent dentition of children with MIH (p = 0.0001). Family income was considered low in 85% of the families of children with MIH in the public system, while in private school it was 18% (p < 0.05). Conclusion. The prevalence of MIH in Araraquara was associated with greater caries experience in the permanent dentition. © 2013 Informa Healthcare.

Análise da microestrutura do amálgama dental quando associado a diferentes materiais intermediários

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência de diferentes procedimentos restauradores na resistência á fratura de dentes com cavidade classe IV submetidos ao clareamento dental interno

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)