Variation In Eruption Research Articles

‘Inversion’ of Impacted Mandibular Third Molar in Ascending Ramus of the Mandible – Report of Rarest Case

‘Wisdom tooth’ or ‘Third molars’ are very interesting tooth not only for oral and maxillofacial surgeons but also for all other specialists of medicine and dentistry. Mandibular third molars are the most often affected tooth and show variations in eruption, size, shape, development, positions and associated with anomalies. The purpose of this article is to present a rarest case of inverted unilateral impacted mandibular left third molar in the ascending ramus of the mandible and was associated with a cystic lesion which is rarely encountered in clinical practice during impaction procedures. Reporting of such interesting and uncommon presentations of dental structures is highly essential to provide utmost care to the patient as well as to make guidelines and protocols for their management.

Accuracy of estimating age from eruption levels of mandibular teeth

Little is documented on the accu-racy of estimating age from alveolar eruption (AE) or partial eruption (PE). The aim of this study was to compare the accuracy of age estimation from eruption levels. Methods tested were Gleiser and Hunt (1955), Garn et al. (1958), Ando et al. (1965), Haavikko (1970) and clinical eruption from Smith et al. (1998). The sample was 946 panoramic dental radiographs from children aged 3-16 years. Left mandibular teeth (excluding third molar) were assessed for eruption level (AE and PE) and root quarters. Methods, teeth and eruption levels were deemed to be accurate if the average difference between estimated and chronological ages was not significant to zero using a t-test (P>0.05). Results show that early erupting permanent teeth were fairly good at estimating age, although there was considerable age variation in eruption. Haavikko incisors and molars at AE and Haavikko and Smith central incisor and second molar at PE estimated age accurately. Root stage of erupting teeth estimated age more accurately than eruption level using Haavikko. These findings suggest that erupting permanent mandibular teeth can be helpful in estimating age.

Polymorphism in the Eruption Sequence of Primary Dentition: A Cross-sectional Study

Primary teeth have shown wide variations in their eruption time among different population. Population specific eruption ages are provided as mean with standard deviations or median ages with its percentile range. This alone will be insufficient for prediction of tooth eruption sequence because they provide no information on the frequency of sequence variation within the pairs of teeth. Norms of polymorphic variation in the eruption sequence can be more useful. This study aims at providing norms for the sequence polymorphism in primary teeth among the children of Mysore population. A cross-sectional study was designed with 1392 children, recruited from December 2015 to June 2016 by simple random sampling method. Tooth was recorded as present or absent. Across the entire possible intra quadrant tooth pair, cases of present-present, absent-absent, present-absent and absent-present and were counted and computed as percentages. Sequence polymorphisms were more common in 82-84 pairs of teeth. Significant polymorphic reverse sequence was observed in 52-54 (9%), 82-84 (35%) in males and 82-84 (18%) in females. There was no polymorphism in maxillary arch in females. The present study provides the baseline data values for sequence variation in primary teeth eruption. To the best of investigators knowledge, there are no previous studies describing the sequence polymorphism in primary teeth in Indian population. The results of this study helps in assessment of eruption sequence problems in paediatric dentistry and in evaluation and prediction of tooth eruption sequence in individual child.

Neuro-fuzzy Classification of Submarine Lava Flow Morphology

This paper presents a novel approach to semi-automated classification of volcanic morphology on the seafloor using high-resolution multibeam sonar bathymetry and side-scan sonar backscatter imagery. The classification methodology combines a fuzzy inference system and neural network theory in an adaptive neuro-fuzzy inference system (ANFIS) and is capable of rapidly classifying submarine lava morphology based on bathymetry-derived surface geometry and backscatter-derived attributes of acoustics and texture. The system has been applied to a study area on a seafloor spreading ridge, the Galapagos Spreading Center (GSC), in order to quantify the distribution and relative abundance of lava flow types, which can be used to indicate variations in eruption and emplacement dynamics. A detailed assessment shows the classification has an overall accuracy of almost 90 percent with a kappa coefficient of 0.84. The neuro-fuzzy method described here is shown to be an efficient and reliable tool for classification of submarine lava morphology.

A review of published sources for age at death in cattle

A survey of the literature for information relevant to estimating age at death in cattle has added detailed data on the age at which particular stages of dental development have been observed, based on sources where direct observations were certainly made. The information is of general interest for archaeozoology and, moreover, has enabled refinements to be made to existing methods for ageing cattle dentition using tooth eruption and wear (Jones and Sadler 2012). The survey presents summaries of published work on longevity in cattle, and on variation in eruption and wear.

How does tooth eruption relate to vertical mandibular growth displacement?

Our objectives were to investigate the eruptive patterns of the mandibular teeth and assess their associations with mandibular growth displacements. Cephalograms for a mixed-longitudinal sample of 124 French-Canadian girls were evaluated between 10 and 15 years of age. Vertical mandibular displacement and mandibular eruption were evaluated by using cranial and mandibular superimpositions, respectively. Multilevel modeling procedures were used to estimate each subject's growth change over time. Stepwise multiple regressions were used to determine the amount and relative magnitudes of variations in mandibular eruption explained by mandibular growth displacement, controlling for vertical maxillary tooth movements. Cubic polynomial models explained between 91% and 98% of the variations in eruption and vertical growth displacement. All curves showed acceleration of eruption until approximately 12 years of age, after which eruption decelerated. The eruption of the mandibular teeth demonstrated greater relative variability than did vertical mandibular growth displacements. Independent of the overall movements of the maxillary molars, inferior mandibular growth displacement explained approximately 54% of the variation in mandibular molar eruption between 10.5 and 14.5 years of age. Inferior mandibular growth displacement and dental eruption followed similar patterns of change during adolescence. Based on their associations and the differences in variability identified, mandibular eruption appears to compensate for or adapt to growth displacements.

The variation in eruption of permanent teeth and loss of deciduous teeth in Western Australian children

The variation in eruption of permanent teeth and loss of deciduous teeth in Western Australian children