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OBJECTIVES: To investigate the relationship between crown/root size and root/canal morphology of maxillary premolars. METHODS: One hundred and thirty-three first (P1) and 110 second (P2) maxillary premolars were used. Mesiodistal and buccolingual diameters and root heights of P1 and P2 were recorded to the nearest 0.01 mm. The number of single and multi-rooted premolars was recorded based on the Turner's classification. Root canal morphology was studied using a clearing technique with Vertucci's classification. Pearson's correlation coefficient was used to analyze the relationship between tooth size and root/canal morphology. RESULTS: Two-rooted P1 was found in 33.9% of male and 22.5% of female. P2 showed a single root in 85.4% of male and 82.6% of female. In case of P1, the number of root canals (P<0.05) and apical foramina (P<0.01) was significantly different between male and female. P1 crown dimensions were larger in double-rooted teeth than in single-rooted ones. Significant differences were observed in buccolingual (P<0.05) and crown area (P<0.05) in females. Root height was smaller in double-rooted than in single-rooted P1. A similar trend was observed for P2 with a larger crown size in teeth with two apical foramina compared with those with a single foramen. CONCLUSIONS: Two-rooted P1 with two or more apical foramina are more commonly seen in males than in females. For P1, the correlation of number of roots and apical foramina was stronger with buccolingual diameter than with mesiodistal diameter in both genders. P1 and P2 with large crown dimensions tend to have multiple roots and apical foramina.

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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.

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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.

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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.

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