ABSTRACT
The etiology of mandibular prognathism has been attributed to various genetic inheritance patterns and some environmental factors. The variation in inheritance patterns can be partly due to the use of different statistical approaches in the respective studies. The objective of this study was to investigate the role of genetic influences in the etiology of this trait. We performed segregation analysis on 37 families of patients currently being treated for mandibular prognathism. Mandibular prognathism was treated as a qualitative trait, with cephalometric radiographs, dental models, and photographs used to verify diagnosis. Segregation analysis of a prognathic mandible in the entire dataset supported a transmissible Mendelian major effect, with a dominant mode of inheritance determined to be the most parsimonious.
Subject(s)
Malocclusion, Angle Class III/genetics , Mandible/abnormalities , Prognathism/genetics , Adult , Cephalometry , Chromosome Segregation , Family Health , Female , Genes, Dominant , Humans , Libya , Likelihood Functions , Male , Middle Aged , Models, Genetic , Quantitative Trait, HeritableABSTRACT
There is no definitive method for the arrangement of artificial teeth in complete denture construction. A new method is introduced whereby the maxillary posterior teeth have been set in approximate positions mediolaterally similar to their natural predecessors. The procedure is based on a constant relationship derived from the natural dentition. Its clinical application proved to be suitable for the arrangement of artificial teeth for complete dentures with minimal errors.
Subject(s)
Denture Design/methods , Denture, Complete, Upper , Tooth, Artificial , Adult , Aged , Bicuspid , Dental Arch/pathology , Dental Occlusion, Balanced , Female , Humans , Jaw, Edentulous/pathology , Male , Middle Aged , MolarABSTRACT
The relationship between the position of the buccal cusps of the natural upper posterior teeth and the distance between the lateral arms of the Gothic arch tracing or the distance between the upper canine teeth has been found to be constant to within +/- 2 mm. This may be of value when setting up artificial teeth for denture patients, enabling them to be positioned close to the natural predecessors.
Subject(s)
Denture Design , Denture, Complete , Adult , Female , Humans , Jaw Relation Record , MaleABSTRACT
A study was carried out to determine the accuracy of different methods of measuring condylar inclination from graphical recordings of condylar paths. Thirty subjects made protrusive mandibular movements while condylar inclination was recorded on a graph paper card. A mandibular facebow and intraoral central bearing plate facilitated the procedure. The first method proved to be too variable to be of value in measuring condylar angles. The spline curve fitting technique was shown to be accurate, but its use clinically may prove complex. The mathematical method was more practical and overcame the variability of the tangent method. Other conclusions regarding condylar inclination are outlined.
Subject(s)
Dental Articulators , Dental Equipment , Dental Occlusion , Mandibular Condyle/anatomy & histology , Female , Humans , Jaw Relation Record , Male , Mandibular Condyle/physiology , Mathematics , MovementABSTRACT
Twenty-five subjects of three nationalities carried out Gothic arch tracings. Measurements between the side arms were compared with the upper intercuspid distances measured in the same subjects. A relationship was found which may be of value in the setting up of anterior maxillary denture teeth.
Subject(s)
Cuspid , Dental Occlusion, Centric , Denture Design , Incisor , Jaw Relation Record , Tooth, Artificial , Adult , Dental Articulators , Female , Humans , MaleABSTRACT
The records of 11 patients referred for treatment of TMJ disorders were used to compare condylar inclination found by drawing a tangent and by using a mathematic technique. Needle point tracing angles were also measured for the same patients and were compared with the condylar inclination. It can be concluded that (1) the mathematic technique outlined records a more accurate condylar angulation, and (2) there is a great variation in condylar inclination values between patients and between left and right sides of the same patient, and (3) there is no direct relationship between condylar inclination and the needle point tracing angle.
