Morphological analysis of cementoenamel junction in premolars of Sri Lankans.

Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important reference point in clinical dentistry as well as in dental radiography. The present study is done to describe the distribution of the mineralized tissue at the cementoenamel junction in relation to various surfaces of the premolars. The study sample consisted of 89 permanent maxillary and mandibular premolars from both males and females extracted for orthodontic reasons. They were stained with carbol fuchsin and observed under a dissecting microscope to identify the following tissue interrelationships at the cementoenamel junction: cementum overlapping the enamel; edge-to-edge relationship between enamel and cementum; gap between the enamel and cementum and enamel overlapping the cementum. The cementum overlapping the enamel interrelationship was predominant in the buccal and lingual surfaces of both first and second maxillary premolars, while the edge-to-edge relationship and the presence of a gap between the enamel and the cementum relationship were abundant in distal and mesial sides. Enamel overlapping the cementum was recorded only in a very small proportion of the sample. A good understanding about the morphological variations at the cementoenamel junction area is very important and this area should be handled carefully during routine dental procedures such as dental bleaching, orthodontic treatment, placement of rubber dam and placement of dental materials.

Hand and handprint measurements in the estimation of stature in a Sri Lankan population / Mediciones de manos y huellas de manos en la estimación de la estatura en una población de Sri Lanka

SUMMARY: The present study was undertaken to generate sex-specific simple and multiple regression models for the estimation of stature using hand and handprint measurements in a Sri Lankan population. The sample comprises 51 males and 66 females in the age range of 20 to 26 years. The stature and eight measurements from each hand and its corresponding print of each subject were collected using standard anthropometric instruments and techniques. All hand and handprint measurements showed significantly positive correlation (p value < 0.05) with the stature in both sexes. Stature prediction accuracy for simple linear regression equations ranged from ±4.41-5.92 cm and ±4.0- 5.22 cm for the left and right hand measurements in males and females, respectively. The corresponding figures for the left and right handprint measurements were ±4.57-5.95cm and ±4.36-5.52 cm, respectively. The highest stature prediction accuracy was shown by the multiple regression models derived from hand measurements. The stature estimating formulae reported in this study using hand measurements have important application in the identification of unknown human remains, particularly when they are partial, mutilated or dismembered. Similarly, it is envisaged that formulae derived from the handprint measurements will be useful in crime scene investigations.

RESUMEN: El estudio se llevó a cabo para generar modelos de regresión simple y múltiple de acuerdo al sexo, para la estimación de la estatura utilizando medidas de manos y huellas de manos en una población de Sri Lanka. La muestra comprendió 51 hombres y 66 mujeres entre 20 a 26 años de edad. Se analizaron la estatura y ocho medidas de cada mano y su impresión correspondiente de cada sujeto utilizando instrumentos y técnicas antropométricas estándar. Todas las mediciones de manos y las huellas de manos indicaron una correlación significativamente positiva (valor de p <0.05) con la estatura en ambos sexos. La precisión de la predicción de la estatura para las ecuaciones de regresión lineal simple varió de ± 4,41 a 5,92 cm y ± 4,0 a 5,22 cm en las medidas de la mano izquierda y derecha en hombres y mujeres, respectivamente. Las cifras correspondientes para las medidas de la huella de la mano izquierda y derecha fueron ± 4,57-5,95 cm y ± 4,36-5,52 cm, respectivamente. La precisión de predicción de la estatura más alta se mostró mediante los modelos de regresión múltiple derivados de las mediciones manuales. Las fórmulas de estimación de la estatura reportadas en este estudio utilizando medidas manuales tienen una aplicación importante en la identificación de restos humanos desconocidos, particularmente cuando son parciales, o se encuentran mutilados o desmembrados. Además, se prevé que las fórmulas derivadas de las mediciones de huellas de manos serán útiles en las investigaciones criminales.

The Porphyromonas gingivalis inhibitory effects, antioxidant effects and the safety of a Sri Lankan traditional betel quid - an in vitro study.

BACKGROUND: The Sri Lankan traditional betel quid (TBQ) which had been extensively used in the country before its colonization is claimed to have antiperiodontopathic effects in the Sri Lankan folklore. However, there is no reported scientific evidence to support the claimed antiperiodontopathic effects mediated by this TBQ. The present study was carried out to investigate the protective effect of the Sri Lankan TBQ in the pathogenesis of periodontitis. METHODS: We investigate the ethyl acetate extract of the Sri Lankan TBQ for its antibacterial effects against the keystone periodontopathic bacterium, P. gingivalis and also its antioxidant potential, which is important to protect the periodontium from oxidative stress. Further, its safety was analyzed using the cytokinesis block micronucleus assay on human peripheral blood lymphocytes (PBLs). RESULTS: Ethyl acetate extract of this TBQ inhibited the growth of P. gingivalis with a minimum bactericidal concentration (MBC) of 125 µg/ml. It was found to be a rich source of polyphenols and displayed considerable DPPH and ABTS radical scavenging activities and a strong ferric reducing antioxidant power. This extract could protect the cultured human gingival fibroblasts from H2O2 induced oxidative stress. In addition, this TBQ extract was not genotoxic to human PBLs even at a concentration of 2.5 mg/ml. Moreover, it exhibited protective effects against bleomycin induced genotoxicity in PBLs. CONCLUSION: Ethyl acetate extract of the Sri Lankan TBQ is a source of natural antibacterial compounds against P. gingivalis. It is also a source of natural antioxidants which can protect human gingival fibroblasts from H2O2 induced oxidative stress. These properties of the TBQ may have contributed to its claimed antiperiodontopathic effects. Besides, it was found to be relatively non-toxic to human cells. Thus this TBQ extract has a huge potential to be developed as a novel adjunctive therapeutic lead against periodontitis.

Regional distribution of interglobular dentine in human teeth.

Interglobular dentine (IGD) is an area of poorly mineralized dentine matrix. It has been reported that there is an association between the retraction of odontoblast processes (OP) and the formation of IGD. A variation of the extent of OP has been described depending on the region of the tooth and age. This study aimed to find out the regional distribution of IGD in human teeth to observe any association between the extent of OP and the pattern of distribution of IGD. Ground sections were prepared from 52 extracted permanent teeth and the presence of IGD was observed in different regions of the crown and the root. The highest occurrence of IGD was found in the cervical and middle thirds followed by intercuspal, and coronal third in the crown. Statistical analysis of data depicted that the occurrence of IGD differed according to the region of the tooth. In roots, the highest occurrence of IGD was seen in the cervical third followed by the middle third. Previous reports have shown that OP extend up to the dentine-enamel junction in the coronal region and to the inner one-third of the cervical region. The varied pattern of distribution of IGD in the crown and root observed in our results corresponds to the above findings. Therefore, it is reasonable to surmise that there is an association between the distribution of IGD and the extent of OP. This allows us to confer that IGD tends to form in areas where OP do not extend to the dentine-enamel junction.

Involvement of GDNF and its receptors in the maturation of the periodontal Ruffini endings.

Our recent study revealed an intense immunoreaction for GDNF and its receptors in the Ruffini endings, primary mechanoreceptors in the periodontal ligament, of young rats. However, no information is available for the expression of GDNF and its receptors during their development. The present study aimed to reveal postnatal changes in the immuno-expression of GDNF, GFRalpha1 and RET in the periodontal Ruffini endings of the rat incisors by double immunofluorescent staining. At postnatal day 3 (PO 3d), no structure with GDNF-, GFRalpha1-, or RET-immunoreaction existed in the periodontal ligament. The PGP 9.5-positive nerve fibers without GDNF- and RET-immunoreaction displayed a dendritic fashion at PO 1w, with a GFRalpha1-reaction found around these nerves. At PO 2w, GDNF-positive terminal Schwann cells occurred near the thick and dendritic axons, a part of which showed a RET-reaction, with no reactive cells near the thin nerves. The terminal Schwann cells became positive for GFRalpha1, but lacked RET-immunoreaction. At PO 3w, when the formation of the periodontal Ruffini endings had proceeded, GDNF-positive terminal Schwann cells began to increase in number. This stage-specific immuno-expression pattern suggests that GDNF is a key molecule for the maturation and maintenance of the periodontal Ruffini endings.