Search results for "Mandibular first molar"
showing 10 items of 37 documents
When less means more: evolutionary and developmental hypotheses in rodent molars.
2012
10 pages; International audience; Tooth number in rodents is an example of reduction in evolution. All rodents have a toothless diastema lacking canine and most premolars present in most other mammals. Whereas some rodent lineages retained one premolar (p4), many others lost it during evolution. Recently, an 'inhibitory cascade' developmental model (IC) has been used to predict how the first molar (m1) influences the number and relative sizes of the following distal molars (m2 and m3). The model does not, however, consider the presence of premolars, and here we examine whether the premolar could influence and constrain molar proportions during development and evolution. By investigating a l…
Inferior alveolar nerve trajectory, mental foramen location and incidence of mental nerve anterior loop
2017
Background: Injury of the inferior alveolar nerve (IAN) is a serious intraoperative complication that may occur during routine surgical procedures, such as dental implant placement or extraction of impacted teeth. Thus, the purpose of this study was to analyze the trajectory of the mandibular canal (MC), the location of the mental foramen (MF) and the presence and extension of an anterior loop of the mental nerve (AL). Study Design: In this cross-sectional study, a total of 348 CBCTs were analyzed. Distances from MC to the surface of the basal, medial and lateral cortical of the mandible were measured at the level of the second molar, first molar and second premolar. Location of the MF rela…
Distance of the alveolar antral artery from the alveolar crest. Related factors and surgical considerations in sinus floor elevation
2016
Background In a variable proportion of maxillary sinuses alveolar antral artery is located close to the residual ridge, increasing the chances for haemorrhagic complications during sinus floor elevation procedures. Material and Methods Retrospective observational study of CBCT explorations performed for implant-treatment planning. The upper first molar area was selected for this study. The relative uncertainty (standard deviation of the measurement divided by its mean and expressed as a percentage from 0% to 100%) was chosen for determining the observational errors. For modeling the chances of AAA detection, the generalized additive models (GAM) approach was chosen. Results A total of 240 m…
Three-dimensional analysis of the physiological foramen geometry of maxillary and mandibular molars by means of micro-CT.
2017
The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide (to a high number, oval) diameters of the physiological foramen were 0.24, 0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal (MB), distobuccal (DB) and …
Bolton ratios in Portuguese subjects among different malocclusion groups
2018
Background Several methods have been described to estimate inter-arch tooth size relationship, such as Bolton's ratios. The aims of this study were to verify the validity of Bolton indexes in a sample of untreated Portuguese subjects based on Angle classification and to evaluate the gender difference. Material and Methods 168 pre-treatment dental casts of orthodontics Portuguese subjects (59 males and 109 females) with different occlusions were used, which were selected randomly from 541 consecutively treated orthodontic patients. The mesiodistal widths from first molar to first molar were measured on each pre-treatment cast to the nearest 0.01 mm using digital caliper, and Bolton's anterio…
Variation in Lingual Nerve Course: A Human Cadaveric Study.
2016
The lingual nerve is a terminal branch of the mandibular nerve. It is varied in its course and in its relationship to the mandibular alveolar crest, submandibular duct and also the related muscles in the floor of the mouth. This study aims to understand the course of the lingual nerve from the molar area until its insertion into the tongue muscle. This cadaveric research involved the study of 14 hemi-mandibles and consisted of two parts: (i) obtaining morphometrical measurements of the lingual nerve to three landmarks on the alveolar ridge, and (b) understanding non-metrical or morphological appearance of its terminal branches inserting in the ventral surface of the tongue. The mean distanc…
Bone quality in the midpalate for temporary anchorage devices.
2009
Objective The aim of the present study was to quantitatively assess the bone quality of the palatal bone from an implantologic standpoint. Material and methods The material consisted of palatal tissue blocks of autopsy material from 22 subjects (19 male, three female), between 18 and 63 years of age. The specimens comprised the anterior part of median palate (APMP) from about 7 mm behind the incisive foramen (first premolar regions), the middle part of median palate (MPMP, second premolar region), and the posterior part of the median palate (PPMP, first molar region). They were prepared in the transversal plane using ground-thin-section technology. The midpalatal areas of the different part…
Root Canal Morphology and Configuration of 179 Maxillary First Molars by Means of Micro-computed Tomography: An Ex Vivo Study
2015
Introduction The objective of this study was to propose a root canal configuration description method and to investigate the root canal system morphology of the maxillary first molar by means of micro-computed tomographic imaging. Methods The root canal configuration, foramina, and accessory canal frequency of 179 maxillary first molars were investigated by means of micro-computed tomographic imaging and 3-dimensional software imaging. The root canal configuration and main foramina number are described from coronal to apical with a 4-digit system. Results The most frequent root canal configurations were 1-1-1/1 (45.8%), 2-2-2/2 (25.1%) and 2-2-1/1 (10.1%) in mesiobuccal roots and 1-1-1/1 in…
Retrospective study of the bone morphology in the posterior mandibular region. Evaluation of the prevalence and the degree of lingual concavity and t…
2016
Background In order to choose the appropriate implant size and to prevent complications, an oral surgeon must know the size and shape of the mandible. In the posterior mandibular region, a lingual undercut is often found and could represent a difficulty hard to manage if a lingual or buccal perforation occur. A large series of computed tomography (CT) images of the mandibular first molar was evaluated and the bone morphology, the prevalence and the degree of the lingual concavity in the first molar region were studied. Material and Methods One hundred and fifty-one computed tomography (CT) examinations of patients were retrospectively evaluated to determine anatomical variations in bone mor…
Maxillary Sinus Anatomy: A Cadaveric Study With Clinical Implications
2009
This study measured maxillary sinus volume, evaluated the location of the semilunar hiatus in correlation to the nasal floor, and the incidence, location, and height of antral septa and discusses their clinical implications. Maxillary sinus volume was quantified in 65 cadavers (130 sinuses) by water application through the semilunar hiatus and measuring the used amount. The location of the semilunar hiatus was identified as distance from the nasal floor. The septa were counted, evaluated, and the size measured from the antral floor. The medium maxillary sinus volume was 12.5 mL (range, 5-22 mL). The medium location of the semilunar hiatus was 25.6 mm above the nasal floor (range, 18-35 mm).…