Sixty-nine adult mandibles (45 male, 24 female) of Thai dry skulls were assessed to determine the size, the orientation and the location of the mental foramen (MF) related to gender and side. The results showed that the usual direction of exit of the MF was in a posterosuperior direction. The most common location of the MF was bilaterally symmetrical and located on the same vertical line with the long axis of the lower second premolar. The mean distances from the MF to the symphysis menti (A), to the posterior border of the mandibular ramus (P), to the lower border of the mandible (mb) and to the buccal cusp tip of the second premolar (cm) were 28.83, 68.85, 14.88 and 24.27 mm, respectively. The mean distances from the alveolar bone crest across the MF to the lower border of the mandible (ab) was 29.97 mm. The mean distance from the buccal cusp tip of the second premolar through the long axis of the clinical crown to the lower border of the mandible (cb) was 39.18 mm. No measurements varied according to the sides (P > 0.05). In contrast, gender differences were significant in all measurements with the longer distances in males (P < 0.05). The mean ratios of A/(A + P), mb/ab and cm/cb in all subjects were 0.30, 0.50 and 0.62, respectively. The values of the three ratios were nearly equal in males and females. Our results may assist surgeons to localize important maxillofacial neurovascular bundles passing through the MF in avoiding complication from local anesthetic, surgical and other invasive procedures.

This study aims to investigate the anatomy of the greater palatine foramen (GPF), greater palatine canal (GPC) and pterygopalatine fossa (PPF) with special reference to the blockage of the maxillary nerve. A correlation between the length of GPC and PPF and the heights of the orbit and the maxilla was also studied using simple linear regression analysis. The morphology of the GPF, GPC and PPF as well as heights of the orbit and the maxilla were assessed in 105 Thai skulls. The thickness of the mucosa over the GPF was also measured from the dissection of 55 cadavers. The results showed that most GPF appeared as an oval foramen located at the palatal aspect of the upper third molar. The GPF was 16.2+/-1.3 mm lateral to the median sagittal plane of the hard palate, 2.1+/-1.3 mm anterior to the posterior border of the hard palate and 5.1+/-1.3 mm from the greatest concavity of the distolateral margin of the hard palate. The mean length of GPC and PPF was 29.7+/-4.2 mm. The mean angles of the GPC in relation to the hard palate and the vertical plane were 57.9+/-5.8 degrees and 6.7+/-5.2 degrees , respectively. In attempting to insert a needle to reach the foramen rotundum through the GPF, 31.7% passed into the orbit while 8.7% passed into the brain. The mean thickness of the mucosa over GPF was 6.7+/-2.3 mm. Two models for estimating the depth of needle injection in maxillary nerve block have been developed as follows: Length of GPC and PPF=19.038+0.314 (orbital height) and length of GPC and PPF=21.204+0.187 (maxillary height). The calculated length combined with the mucosal thickness was the estimated depth of needle injection. In conclusion, our results concerning the GPF, GPC and PPF will provide the useful reference for clinicians to anesthetize the maxillary nerve with a greater degree of success.

This study aims to investigate the shape, height, and location of the lingula in relation to surrounding structures for sagittal ramus osteotomy. Dried Thai mandibles were studied and compared with other races. From both sides of 92 mandibles, the shape of the lingula was classified into triangular, truncated, nodular, or assimilated types. Of 92 mandibles, 146 sides with at least a premolar and a molar on the same side were selected for distance measurement. Height of the lingula was measured from the lingular tip to the mandibular foramen. The location was determined by five distances from the lingular tip to: the anterior and the posterior borders of the mandibular ramus, the mandibular notch, the distal surface of the mandibular second molar, and the occlusal plane. The results showed that truncated lingulae were most frequently found (46.2%) and most appeared to be bilateral (71.7%). Triangular, nodular, and assimilated shapes presented in 29.9%, 19.6%, and 4.3%, respectively. The mean lingular height was 8.2 +/- 2.3 mm. The lingula was located at 20.6 +/- 3.5 mm from the anterior border of the mandibular ramus and 16.6 +/- 2.9 mm from the mandibular notch. In the majority of the mandibles studied, the lingula was located above the occlusal plane. In conclusion, the shape and metric characteristics of the lingula in relation to surrounding structures in Thais vary from other races. All parameters associated with the lingula should be considered for sagittal ramus osteotomy to avoid intraoperative complications.

The objectives of this study were to determine the prevalence, size, shape and location of the oral tori in 1,520 Thai dental patients and to investigate the relationship between the findings with age and gender. The prevalence rates were 60.5% for torus palatinus (TP) and 32.2% for torus mandibularis (TM). The concurrence of TP and TM was noted in 23.2% subjects. The peak incidence of TP and TM was in the third decade of life. TP affected more women than men (70.5 vs. 48.8%, P < 0.001). Most TP were found in spindle shape (56%), small size (52.1%) and located at premolar region (47.4%). The occurrence of TM was higher in men than in women (36.3 vs. 28.6%, P = 0.002). TM was found most common in small size (65.6%), as bilateral multiple nodes (59.3%) and usually located at the premolars (89.2%). The age and gender-related differences with the size of tori were noted. Subjects who had larger TP or TM were older than those who had smaller TP or TM (P < 0.001 and P = 0.001, respectively). Women were more likely to have larger TP whereas men tended to have larger TM. This study showed high prevalence rates of TP and TM in dental patients and the occurrences were related to gender.

Gelatinases have been shown to be regulated by many cytokines and growth factors, and have been implicated in the pathogenesis of certain autoimmune diseases via tissue destruction. High levels of several cytokines, including IFN-gamma and TNF-alpha, have been demonstrated in the salivary gland microenvironment of patients with Sjogren's syndrome (SS). How these cytokines may be contributing to the pathogenesis of this disease is not well understood. We hypothesized that IFN-gamma with or without (+/-) TNF-alpha could be playing a role in the pathogenesis of SS via the regulation of matrix metalloproteinase (MMP) levels. This study examined the role of IFN-gamma and (+) TNF-alpha in the regulation of the matrix metalloproteinases, MMP-2 (72 kD gelatinase A) and MMP-9 (92 kD gelatinase B). A human salivary gland cell line (HSG) has been used as a possible in vitro model to study the role of IFN-gamma + TNF-alpha in the pathogenesis of SS. The HSG cell line, in the presence of IFN +/- TNF-alpha, displays increased MMP-2 and MMP-9 gelatinolytic activity, protein and RNA levels. The increase in MMP activity was partially blocked with an antibody against the IFN-gamma receptor, and this was associated with a complete inhibition of the previously described IFN-gamma +/- TNF-alpha antiproliferative effect. However, incubation of IFN-gamma treated HSG cells with the synthetic MMP inhibitor BB94 did not alleviate this antiproliferative effect. In addition, we demonstrate that there are very high levels of MMP-9 in the saliva of patients with SS when compared to healthy control subjects. These data suggest that cytokines could be regulating MMP production by salivary epithelial cells and thus indicate a potential role for these cells in the pathogenesis of SS.