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.

Supraorbital nerve exits: positional variations and localization relative to surgical landmarks.

Significant variations exist in the occurrence, form, and position of supraorbital nerve exits through the frontal bone. Detailed knowledge of the positional variations of supraorbital exits is important to ensure safe and successful regional anesthesia, and to avoid iatrogenic nerve injuries during surgery of the orbitofacial region. Supraorbital nerve exits from 116 sides of 58 dry intact adult skulls (37 male and 21 female) in a Sri Lankan population were examined to determine the morphological features and the precise position in relation to the facial midline, temporal crest of frontal bone, and frontozygomatic suture. A majority of supraorbital nerve exits existed as notches (73.8%) and the rest as foramina (26.2%). Accessory exits were seen in 18.9% skulls. Of the skulls examined, 55.1% displayed bilateral supraorbital notches, 8.6% had bilateral supraorbital foramina, and 36.3% had a notch on one side and a foramen on the contralateral side. In males, the supraorbital nerve exit was located 23.64±3.49 mm laterally from the facial midline, 27.86±2.76 mm medially from the temporal crest of the frontal bone, 28.66±2.56 mm from the frontozygomatic suture, and 2.12±1.07 mm above the supraorbital margin in the case of a foramen, and in females 22.69±3.28 mm laterally from the facial midline, 26.32±3.02 medially from temporal crest of frontal bone, 27.29±3.05 from the frontozygomatic suture, and 2.99±1.49 mm above the supraorbital margin when it existed as a foramen. The observations made in this study will be useful when planning a supraorbital nerve block and surgery in the supraorbital region.

Morphometric Analysis of the Infraorbital Foramen: The Clinical Relevance.

The present study was conducted to ascertain the shape, size, presence of accessory foramina, direction, and the precise position of the infraorbital foramen (IOF) in relation to the inferior orbital margin (IOM), anterior nasal spine (ANS), nasion (Na), maxillary teeth, and supraorbital foramen/notch (SOF/N) in adult skulls in a Sri Lankan population. Fifty-four skulls (42 males and 12 females) were analyzed. The IOF was oval in shape (38.6% and 36.3% on the right and left side, resp.) in a majority of skulls. The direction of the IOF was mostly medially downward (48.6%). Accessory foramina were found in 7.4% of the skulls. The infraorbital foramina were located at a mean distance of 6.52 ± 2.03 mm and 7.30 ± 1.57 mm, vertically below the IOM on the right and left side, respectively; 33.81 ± 2.68 mm and 34.23 ± 2.56 mm from the ANS on the right and left side, respectively; and 42.37 ± 3.52 mm and 42.52 ± 3.28 mm from the Na on the right and left side, respectively. In relation to the upper teeth the majority of IOF (37.5% and 55.9% on the right and left side, resp.) were located in the same vertical axis as the tip of the buccal cusp of the maxillary second premolar tooth.

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.

Morphology of the cemento-enamel junction in premolar teeth.

The present study attempted to describe the distribution of the mineralized tissues that compose the cemento-enamel junction, with respect to both the different types of permanent premolars of males and females and the various surfaces of individual teeth. The cervical region of ground sections of 67 premolars that had been extracted for orthodontic reasons were analyzed using transmitted light microscopy to identify which of the following tissue interrelationships was present at the cemento-enamel junction: cementum overlapping enamel; enamel overlapping cementum; edge-to-edge relationship between cementum and enamel; or the presence of gaps between the enamel and cementum with exposed dentin. An edge-to-edge interrelation between root cementum and enamel was predominant (55.1%). In approximately one-third of the sample, gaps between cementum and enamel with exposed dentin were observed. Cementum overlapping enamel was less prevalent than previously reported, and enamel overlapping cementum was seen in a very small proportion of the sample. In any one tooth, the distribution of mineralized tissues at the cemento-enamel junction was irregular and unpredictable. The frequency of gaps between enamel and cementum with exposure of dentin was higher than previously reported, which suggests that this region is fragile and strongly predisposed to pathological changes. Hence, this region should be protected and carefully managed during routine clinical procedures such as dental bleaching, orthodontic treatment, and placement of restorative materials.

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.

Age-related changes in crown and root length in Sri Lankan Sinhalese.

Exploration of the relationship between tooth dimensions, body size, and age is important in paleontology, forensic odontology and aesthetic dentistry. It is reasonable to speculate that tooth length is associated with stature since teeth contribute to facial height. This study aimed to determine whether there was an association between tooth length and stature and age in a sample of Sri Lankan Sinhalese. Extracted teeth of adults, whose age, sex and standing height were known, were used for measurements. The total tooth length (TTL), crown length (CL) and root length (RL) of permanent maxillary central (68) and lateral (67) incisors were measured using a caliper. Statistical analyses were performed with the software MINITAB version 14.0 (Minitab Inc, USA). Mean age and standing height were 47.81 yr and 152.15 cm, respectively. There was no significant correlation between stature and tooth lengths of incisors. However, age was found to have a significant correlation with RL, (r = 0.26, P < 0.05) and CL (r = -0.28, P < 0.05). Absence of an association between tooth length and stature indicated that the genetic linkage between tooth size and stature was weak, suggesting that determination of stature from tooth lengths is unwarranted. The association between tooth length and age indicates the importance of root length in age determination.

Morphological changes in oral mucosae and their connective tissue cores regarding oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a chronic disease of the oral cavity characterized by an inflammatory reaction followed by severe fibro-elastic changes. The aim of the present study was to investigate the three-dimensional morphological changes in the connective tissue cores (CTCs) of the oral mucosa in OSF. The sample consisted of buccal mucosal biopsies from ten human subjects ranging in age from 40-45 years; five of them were clinically diagnosed as having moderate to severe OSF, and the remaining five served as unaffected controls. Half of each biopsy was formalin-fixed and paraffin-embedded for light microscopy, while the other half was fixed in a Karnovsky's solution, treated with HCl to exfoliate the epithelium, and processed for examination under a scanning electron microscope (SEM). Oral submucous fibrosis biopsies exhibited heavily packed aldehyde fuchsin-positive fibers (i.e. elastic fibers) in the submucosa under the light microscope. Broad bundles of collagen fibers were seen in a concentrated manner in the deeper layers. Scanning electron microscopy of the buccal mucosa in OSF showed the finger-shaped CTCs to be attenuated beneath the epithelium at the initial stages of the disease. Patchy degenerative areas lacking the CTCs were observed in advanced cases. These degenerative areas increased gradually with the progression of the disease. Highly fibrosed cases showed severe degeneration of the CTCs, resulting in a smoothening of the connective tissue surface in the buccal mucosa.