Comparing fracture resistance on bovine incisors restored by tooth fragment reattachment versus direct composite restoration techniques.

BACKGROUND/AIM: Anterior teeth are prone to traumatic dental injuries (TDIs). Although a number of techniques ranging from original tooth fragment reattachment (TFR) to direct composite restoration (DCR) can be used to restore uncomplicated crown fractures, there is no consensus on which method is best. The purpose of this study was to investigate the fracture resistance of bovine incisors restored by two different techniques (TFR and DCR) in three different fracture models. MATERIALS AND METHODS: Sixty extracted bovine lower incisors were randomly divided into three groups (n = 20). Angle, oblique, or transverse sections of all the teeth in a group were prepared by using a disk. The cut surfaces were scanned, and the cross-sectional areas (CSA) of the enamel and dentin were measured. Half the teeth in each group were restored by DCR (n = 10) and the other half by TFR (n = 10). The forces required to fracture the restored teeth were then measured using a Universal testing machine, and the fracture modes were analyzed (cohesive, adhesive, or mixed). RESULTS: No statistically significant differences between the TFR and DCR restorations were detected for total and enamel CSAs in any of the restoration shapes (p > .067). The fracture forces required to break DCR angle and transverse restorations were significantly greater than for the corresponding shapes restored with TFR (p < .033). However, the difference in the forces needed to fracture oblique section restorations by DCR or TFR was not statistically significant (p = .239), despite a similar trend (143.4 ± 51 N and 120.9 ± 25 N, respectively). CONCLUSION: This study revealed that a greater force is required to fracture teeth restored by the DCR than by the TFR technique, especially for a transverse section. This demonstrates that restoring a fractured tooth provides a superior outcome compared to reattaching the fractured fragment.

Sex estimation using computed tomography of the mandible.

Sex estimation of skeletal parts is of great value even in the DNA era. When computed tomography (CT) facilities were introduced to forensic institutes, new possibilities for sex estimation emerged. The aim of this study was to develop a CT-based method for sex estimation using the mandible. Twenty-five CT-based measurements of the mandible were developed and carried out on 3D reconstructions (volume rendering) and cross sections of the lower jaw of 438 adult individuals (214 males and 224 females). Intraobserver and interobserver variances of the measurements were examined using intraclass correlation coefficient (ICC) analysis. Five discriminant functions were developed using different states of completeness of the mandible. The success rates of these equations were cross validated twice. The measurements were found to be highly reliable (for intraobserver 0.838 < ICC < 0.995 and for interobserver 0.71 < ICC < 0.996). For a complete mandible, the correct classification rate was 90.8%. For incomplete mandibles, the correct classification rates varied from 72.9 to 85.6%. Cross-validation tests yielded similar success rates, for the complete mandible 89% and for the incomplete mandible 67.5 to 89%. We concluded that CT techniques are appropriate for estimating sex based on the mandible size and shape characteristics. Suggested discriminant functions for sex estimation are given with data on the correct classification rates.

Expression of the homeostasis-related markers, maspin, heat shock proteins 70 & 90, glutathione S-transferase, aquaporin 5 and NF-kB in young and old labial and palatal salivary glands.

Intraoral salivary glands undergo remarkable age-related morphologic changes. This study investigated the expression of a panel of molecular markers known for cellular homeostatic activity, dependent on age and location of the salivary glands. Samples taken from healthy subjects were classified according to age ("young" <45 years, n=51, and "old" ≥60 years, n=45) and location (lip, n=47 and palate, n=49). They were immunohistochemically stained for mammary serine protease inhibitor (maspin), heat shock protein (HSP)70, HSP90, glutathione S-transferase (GST), aquaporine5 (AQP5), and nuclear factor kappa-B (NF-κB) for assessment of their expression in acini and ducts, and in cytoplasmic and nuclear compartments. Results were expressed as the mean percentage of positively stained component per age group, gland location and type of cell and cellular compartment. Statistical analysis was performed by two-way ANOVA and crosstabs. The expression of maspin was lower in the old group in both the palatal and labial glands (acini and ducts, cytoplasm and nuclei) compared to the young group (p<0.05). In both age groups, when compared to labial glands, palatal glands exhibited higher expression of HSP70 (p<0.05) and lower expression of AQP5 (p<0.001) and NF-κB (p=0.018). Collectively, the low expression of factors capable of preserving cellular homeostasis (i.e., maspin and AQP5) vis-à-vis a high expression of factors that are also related to cell survival (i.e., HSPs) that was demonstrated in the old palatal glands may point to their high vulnerability to undergo selective phenotypic changes.