ETD Collection

Permanent URI for this collectionhttps://wiredspace.wits.ac.za/handle/10539/104


Please note: Digitised content is made available at the best possible quality range, taking into consideration file size and the condition of the original item. These restrictions may sometimes affect the quality of the final published item. For queries regarding content of ETD collection please contact IR specialists by email : IR specialists or Tel : 011 717 4652 / 1954

Follow the link below for important information about Electronic Theses and Dissertations (ETD)

Library Guide about ETD

Browse

Subject: search.filters.subject.Mandible

Search Results

Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    A new classification and treatment protocol for mandibular condylar fractures
    (2019-03-25) Rikhotso, Risimati Ephraim
    Introduction Despite decades of study, a consensus on therapeutic approaches to condylar fractures remains elusive, and the vexing question of invasive (open reduction or surgical treatment) or non-invasive (closed treatment or non-surgical treatment) therapy remains to be definitively answered. This lack of a standardised treatment protocol for condylar fractures often results in the haphazard and often subjective application of treatment schedules. This study aimed to present a new classification system for mandibular condylar fractures. Furthermore, this randomised, clinical single-centre study compared the outcomes of mandibular condylar fractures treated by closed treatment with those treated by open reduction with rigid internal fixation. Factors which influence treatment outcomes of mandibular condylar fractures were also evaluated, and used to design a mandibular condyle scoring system and management protocol. Materials and methods Patients older than 18 years withWits Types II, III and IV mandibular condylar fractures were prospectively randomised into the open and closed treatment groups. In the open reduction and internal fixation (ORIF) group fractures were approached via a retromandibular incision. In the closed treatment (CT) group patients were placed in intermaxillary fixation (IMF) for 1 week. In both groups, elastic guidance was used for 5 weeks and physiotherapy for 3 months. Both groups were assessed for parameters vi such as mouth opening, occlusion, range of movement, TMJ function and complications at 1 and 6 weeks, 3, 6 and 12 months. Results A total of 116 patients with MCFs were included in the study. Of these, only 10 (9%) were female. There was a total of 132 fractures (100 unilateral, 16 bilateral). Of the 100 unilateral fractures 41 occurred on the left side and 59 on the right. The most common type of fracture was Type IIB (89.7%) followed by Type III (7.4%) and Type IV (2.9%). The aetiology of the fracture was alleged assault in 76 patients (65.5%), road traffic accident in 17 (14.6%) and falls in 16 (13.7%). Symphyseal and parasymphyseal fractures were the most commonly associated fractures (n=75) followed by body (n=21) and angle fractures (n=7). Only 15 (13%) patients had isolated mandibular condylar fractures (MCFs). Sixty eight (59%) patients were treated by CT and 48 (41%) patients were treated by ORIF. After a follow-up of 12 months, no significant differences were observed between the two groups for mouth opening, protrusion, pain, TMJ function and laterotrusive movements to the non-fractured side. Laterotrusive movements towards the fractured side in unilateral cases were, however, better in the closed group than in the open group (p=0.038). In the closed group, 14 (21%) patients had malocclusion and 18 (27%) patients had deviations greater than 2 mm. In the open group, 9 patients had transient facial nerve palsies which resolved within 3 months, 2 patients had hypertrophic scars, 3 had keloids, 4 had parotid fistulae which resolved within 6-8 weeks, 1 had malocclusion, and 3 had deviations.
  • No Thumbnail Available
    Item
    Morphology and function: aspects of mandibular development and growth at different stages across the lifespan
    (2017) Hutchinson, Erin Frances
    During development and growth, the mandible adapts to accommodate increased biomechanical loading associated with the development and growth of the tongue and the dentition. Biomechanical loads play a vital role in the modelling and remodelling of bone, with site-specific effects on bone density. In the functional transition from the prenatal to the postnatal period, biomechanical loading appears to be intensified and may affect the morphology of the mandible. The aim of this study was to analyze the growth and development of the human mandible during the functionally complex perinatal period of growth in order to investigate biomechanical effects. As edentulism modifies the biomechanical landscape of mastication, the effects of tooth loss on the morphology of the adult mandible were also investigated. Seven hundred and seventeen mandibles were sourced from cadaveric and skeletonized remains forming part of the Paediatric Collection, Raymond A. Dart Collection of Human Skeletons and Johannesburg Forensic Paediatric Collection, University of the Witwatersrand. The morphometric growth relationships between the mandible and tongue were initially investigated. A strong correlation between changes in the dimensions of the mandible and tongue was observed between 20 gestational weeks and 2 years. It was hypothesized, that mandibular growth was directed by the growth of the tongue. This would result in areas of increased bone modelling and remodelling, directly associated with the attachment of the tongue to the mandible and would manifest in areas of lower density bone. Subsequently, variations in bone mineral density of the body of the mandible were assessed. The lingual surface had significantly higher bone density values when compared to the external surface across the period of 30 gestational weeks to 5 years. Variations in the bone density across the external surface of the mandible followed the patterns of postnatal dental development. Thus, the effects of edentulism on the morphology of the adult mandible were also considered. The edentulous mandible had a shorter alveolar height and mandibular body length as well as more obtuse gonial and mental angles, when compared to the dentate mandible. Thus, changes in the morphology of the mandible over time appear to be indicative of an altered mandibular morphology prompted by a changing biomechanical landscape.
  • No Thumbnail Available
    Item
    The transitional dentition of cercopithecus aethiops with special reference to the mandibular anterior teeth.
    (1980) Gavronsky, Gerald
    This dissertation studies the development of the anterior successional teeth prior to eruption, their eruption paths and position of emergence of these teeth in Cercopithecus aethiops, the vervet monkey. The eruption of the permanent dentition is divided into four stages, equivalent to four chapters, with a fifth chapter devoted to an analysis of the pattern or sequence of eruption. This pattern is compared to those of other workers and possible reasons for tooth sequence polymorphism are discussed. Twenty three skulls, fourteen female and nine male are examined and a representative sample chosen from each phase of dental development for dissection. Photographs of each stage are presented, accompanied by a descriptive text but no measurements are recorded. This is a visual and descriptive presentation which 'opens the window' to those aspects of the Cercopithecoid dentition which are not as readily observable by other methods such as clinical examination or radiography.
  • No Thumbnail Available
    Item
    A morphological study of the lingula in South Africans in relation to sagittal split osteotomy
    (2014-09-02) Munsamy, Clinton
    The sagittal split ramus osteotomy is a common procedure used to correct jaw deformities. The lingula is an important anatomical landmark that is used as a reference to position the horizontal osteotomy cut on the medial aspect of the mandible. Knowledge of its position in relation to surrounding anatomical structures is essential in order to prevent complications related to the procedure. The aim of this study was to provide medical and dental practitioners with useful data regarding the position of the lingula in relation to surrounding anatomical landmarks. Such data may be of clinical relevance when performing surgery on the mandibular ramus and when providing anaesthesia for routine dental procedures. The study involved anthropometric measurements on adult dry mandibles obtained from the ‘Dart Collection’ at the School of Anatomical Sciences, University of the Witwatersrand, Johannesburg. A total number of 113 adult human dry mandibles were studied. From these specimens, 201 sides were examined. The most common shape of lingula noted within the study was that of the truncated type which was found in 38.8% of cases, followed by the triangular, nodular and assimilated types which comprised 30.8%, 21.4% and 8.9% respectively. The average distance of the tip of the lingula from the anterior border, posterior border and sigmoid notch the ramus of the mandible was approximately 20.15mm, 16.77mm and 16.3mm respectively. The average distance of the tip of the lingula from the mandibular second molar tooth was found to be 33.3mm. The lingula was above the level of the occlusal plane in 63.7% of cases, by an average distance of 6.5mm. The width and height of the mandibular foramen exhibited great variation. Anatomical differences in Caucasian and Black mandibles were noted, with the 4 rami of Caucasian mandibles generally being smaller in dimension compared to black mandibles. The anatomic data provided by this study may assist surgeons to locate and identify the lingula without difficulty, and avoid intraoperative complications. The data presented has a direct relevance to clinical practice and teaching.
  • No Thumbnail Available
    Item