Effects of Preheating and Sonic Delivery Techniques on the Internal Adaptation of Bulk-fill Resin Composites.

OBJECTIVE: To compare the effects of conventional (hand-placed), sonic, or preheated insertion techniques on the internal adaptation of bulk-fill resin composites. METHODS AND MATERIALS: A total of 150 freshly extracted human third molars were used to prepare standardized cylindrical occlusal cavities. Teeth were divided into five main groups according to the resin composites: 1 incremental (Clearfil Majesty Posterior [CMP]) and four paste-like bulk-fill (SonicFill 2 [SF2], VisCalor bulk [VCB], Filtek One bulk-fill restorative [FBR], and Tetric EvoCeram bulk-fill [TEB]). Each main group was divided into three subgroups according to the placement technique: conventional, preheating, and sonic delivery (n=10). In the conventional placement technique, cavities were filled manually. In the sonic insertion technique, a specific handpiece (SonicFill Handpiece; Kerr Corporation) was used. In the preheating technique, a heating device (Caps Warmer, Voco, Cuxhaven, Germany) was used to warm the resin composites before placement. Internal voids (%) of the completed restorations were calculated with microcomputed tomography. Data was analyzed with two-way analysis of variacne followed by Tukey's multiple comparisons test (α=0.05). RESULTS: All resin composites showed fewer internal gaps with preheating compared with the conventional placement (p<0.05). For all resin composites other than SF2, preheating provided fewer internal gaps than that of the sonic placement (p<0.05). Sonic placement led to fewer internal gaps compared with the conventional placement, but only for SF2 and FBR (p<0.05). For the conventional placement, the lowest gap percentage was observed with the incremental resin composite (CMP, p<0.05). Among all groups, the lowest gap percentages were observed for preheated VCB followed by sonically inserted SF2 (p<0.05). CONCLUSION: The best internal adaptation was observed in sonically inserted SF2 and preheated VCB, which were the manufacturers' recommended insertion techniques. Preheating considerably improved the internal adaptation of all resin composites, except for that of SF2.

Analysis of pulp chamber of primary maxillary second molars using 3D micro-CT system: an in vitro study.

AIM: The aim of this study was to determine the positional relationship between the crown contour and the pulp chamber as well as the morphological characteristics of the pulp chamber using micro-CT in order to plan, in restorations of deciduous maxillary second molars, reconstructions with a volumetric rendering programme. STUDY DESIGN: In total 16 deciduous maxillary second molar teeth (8 from boys, 8 from girls) were used. The positional relationship between crown contour and pulp chamber was three-dimensionally observed by micro-CT. Differences in sex, dentin thickness and pulp volumes were evaluated using chi-square and paired t-tests. Differences were considered significant when P < 0.05. RESULTS: Dentin thickness was found to be 2.8 mm ± 0.2, mesiobuccally 3.15 mm ± 0.2 distobuccally 3.8 ± 0.3, which was statistically significant (p ≤ 0.05). The pulp volume for boys was 77 mm³ ± 4, for girls 64 mm³ ± 5, with a statistical significance (p ≤ 0.05). CONCLUSIONS: General differences could play a role when planning a treatment for a child; however for both genders it should be noted that mesiobuccal pulp horn is most likely to get exposed during cavity preparation.

Determining treatibility of primary teeth with pulpal exposure.

OBJECTIVES: To determine rates of pulpal exposure during caries removal with an excavator or a bur, to assess success rates of vital pulp therapies in both cases, to analyze pulpal bleeding as an indicator of primary teeth treatability. STUDY DESIGN: Of the 352 primary mandibular molars with deep carious lesions, 141 with pulp exposed during the removal of caries were grouped according to type of instrument causing pulpal exposure and existence of bleeding at the exposure site. Teeth suitable for direct pulp capping or formocresol pulpotomy were treated and followed up for two years. RESULTS: The difference between the rates of pulpal exposure with an excavator (52.5%) or a bur (47.5%) was insignificant. The treatment success rate of teeth with pulp exposed by an excavator (15.8%) was significantly lower than teeth with pulp exposed by a bur (48.8%), regardless of whether bleeding existed at the exposure site or not; however when bleeding existed, this difference was insignificant (15.8% and 40.6%, respectively). CONCLUSIONS: Pulpal exposure possibility during caries removal caused by an excavator and a bur was similar the treatment success rate was lower when the exposure was caused by an excavator the existence of pulpal bleeding resulted in mistakes in diagnoses.

Investigation of pneumatized articular eminence in orthodontic malocclusions.

OBJECTIVES: To investigate the prevalence and characteristics of pneumatized articular tubercule (PAT) or eminence in an orthodontic patient population and to examine the possible correlations between different orthodontic malocclusions and pneumatized articular eminence types. SETTING AND SAMPLE POPULATION: Department of Orthodontics, Faculty of Dentistry, Ankara University, Turkey. MATERIAL AND METHODS: Pre-treatment panoramic radiographs were evaluated retrospectively from files of 1405 children and adolescents (459 boys and 946 girls) having various types of malocclusions. Diagnosis of PAT on the radiographs was recorded only if unequivocal pneumatization of the articular eminence could be seen or if the defect was located in the articular eminence posterior to the zygomaticotemporal suture, as a well-defined unilocular- or multilocular radiolucency. PAT was classified as unilocular or multilocular and unilateral or bilateral. Chi-square test was performed to evaluate age, gender, localization, type of malocclusion and prevalence differences. RESULTS: Sixty-six pneumatized articular eminences were found in 48 patients, representing a prevalence of 3.42%. The results of chi-square test showed no statistically significant differences considering age (p = 0.516), gender (p = 0.719), type of malocclusion (p = 0.155) and localization (p = 0.738). CONCLUSIONS: A relatively high rate of pneumatized articular eminence was observed among patients with orthodontic malocclusions (3.42%) when compared to the general population studies. Knowledge about these structures is helpful for the interpretation of cephalometric and panoramic radiographs and provides valuable information especially prior to temporomandibular joint surgery to avoid intra-operative reconstruction and complications.

Radiographic evaluation of third molar development in relation to chronological age among Turkish children and youth.

A sharp increase in forensic age estimation of living persons has been observed in recent years. However, ethnic populations residing in different countries have been insufficiently analyzed. According to 2004 data compiled by the Essen-based Turkey Research Center, there are 3.8 million Turkish people living abroad, and 3.2 million of them reside in European Union countries. Despite the high number of Turks living abroad, little is known about third-molar development for forensic application in this population. Hence, it was considered worthwhile to determine the developmental stages of the third molar in a group of Turkish population, to assess chronological age estimation based on the developmental stages, and to compare third molar development according to sex, age and location. Orthopantomograms of 1134 Turkish patients, ages 4-20 years were examined and third-molar developmental stages were evaluated based on Demirjian's classifications. Orthopantomograms were scored by two different observers, and Wilcoxon matched-pairs signed-ranks test used to test intra- and inter-observer reliability revealed a strong agreement between both intra- and inter-observer measurements. Linear regression analysis was performed to correlate third-molar development and chronological age, and further statistical analysis was performed to determine the relation between sex, age and location. Results showed a strong linear correlation between age and molar development (males: r(2)=0.57; females: r(2)=0.56). Mineralizations of left and right third molars were compared using Wilcoxon tests, and no statistical differences were found. No significant differences were found in third-molar development between males and females. Mandibular third molar crypt formation was observed in 2.4% of patients at age seven and maxillary third molar crypt formation was observed in 1.3% of patients at age seven. A strong correlation was found between third-molar development and chronological age. Among the Turkish population, third molar crypt formation is observable at as early as 7 years in both the mandible and maxilla. Agenesis can be determined conclusively if no radiolucent bud is present by age 14.

Radiographic evaluation of pneumatized articular eminence in a group of Turkish children.

OBJECTIVES: The purpose of this study was to determine the prevalence and characteristics of patients with pneumatized articular eminence (PAT) in a group of Turkish children in order to make a contribution to pneumatization phenomenon in childhood. METHODS: 1049 panoramic radiographs were retrospectively evaluated. PAT was defined as non-expansile, non-destructive cyst-like radiolucency in the zygomatic process of the temporal bone, which appears similar to the mastoid air cells. It was classified as unilocular or multilocular on the radiograph. Statistical comparison of gender, age and localization was performed using a chi-square test (P<0.05). RESULTS: Twenty-four pneumatized articular eminences were found in 17 patients, representing a prevalence of 1.62%. Patients with pneumatized articular eminence had a mean age of 11.2 (SD 3.13) years with a range of 7-16 years. Eight cases (47.1%) occurred in girls and nine cases (52.9%) occurred in boys. The results of statistical tests showed no statistically significant differences among the groups with respect to gender, age and localization (P<0.05). CONCLUSIONS: Pneumatization of accessory air cells begins before puberty, contrary to the general opinion and statements. Knowledge about these structures is helpful for the interpretation of imaging such as panoramic radiographs and provides valuable information to understand the spread and differential diagnosis of pathological entities in this region.