The maxilla and mandible may be affected by a wide variety of lesions of developmental, neoplastic or inflammatory origin. These lesions have a vast array of clinical and radiographic presentations from which a dentist forms a clinical provisional diagnosis and treats the lesions accordingly. The aim of this study was to determine the range, demographic and clinical features of all histologically diagnosed radiolucent jaw lesions in a New Zealand population over a twenty-year period. Additionally, the provisional diagnosis was compared to the histopathological diagnosis in an effort to gain an insight into the difficulties practitioners face in clinically diagnosing radiolucent jaw lesions. Material and Methods: From the histopathology diagnostic service at the University of Otago School of Dentistry all specimens with a diagnosis of a radiolucent jaw lesion between 1986 and 2006 were retrieved and classified into six diagnostic categories. For each lesion the age, gender, site, clinical presentation, clinicians provisional diagnosis and the final histological diagnosis was gathered and analysed. Results: During the study period 4983 specimens were identified as radiolucent jaw lesions. The diagnostic category with the largest number of specimens was inflammatory lesions (72.8%), followed by developmental odontogenic cysts (21.8%). Malignant tumours accounted for less than 1% of all specimens. Concordance of provisional and histopathological diagnoses ranged from 81.0% for nasopalatine duct cyst to 0% for the majority of intra-osseous malignant tumours. Conclusions: The range and demographic features of radiolucent jaw lesions in this study are comparable to that of other populations with a European majority. No radiolucent jaw lesion can be reliably accurately diagnosed from clinical presentation and radiographic appearance alone.

Inaug.-diss.--Gōttingen.

Master of Dental Surgery / A study of the masticatory apparatus can be divided into the following sections:- Bony structure Teeth and supporting structures Temporomandibular articulation (and ligaments) Muscles of mastication (elevation and depression) Muscles of facial expression and deglutition Neurology Vascular and lymphatic supply This work is concerned with the muscles of mastication and the positions and movements of the mandible for which they are responsible. It is of course impossible to divorce this particular aspect from the others, as they are all completely interdependent, and, in particular, a study of the neurology is essential for an understanding of the function of the muscles of mastication. When all parts of the apparatus are in the correct functional relationship they operate with the greatest efficiency and the least effort. The jaws and neuromuscular system should be in correct relationship to avoid neuromuscular tension and damage to the component parts of the masticatory system.

Master of Science / A mechanical stimulus producing stretch in human or animal muscle may evoke a reflex response in the muscle that tends to oppose the length change. In decerebrate preparations, limb flexion generates a tonic stretch reflex that manifests as a sustained increase in resistance (Liddell and Sherrington, 1924; Widmalm, 1976b). This tonic response is not readily apparent in the conscious human subject, however, the phasic response may be observed as a burst of action potentials produced by the synchronous firing of several motor units, and as such represents the classic tendon reflex. The analogous compound action potential in the jaw musculature may be demonstrated following a sudden downward mechanical impulse to the mandible in the human or animal subject (Goodwill, 1968; Matthews, 1976) and has been termed the jaw-closing reflex or the jaw jerk reflex, the latter so named in view of its similarity to the knee-jerk and other tendon reflexes induced by sudden stretch (Goodwill, 1968; Munro and Griffin, 1971; Tardieu, Tabary and Tardieu, 1973). The use of the term “jaw jerk” to describe this reflex may be inappropriate as it has been used to describe a sudden opening movement (Riblet and Mitchell, 1971). It would appear preferable therefore to avoid the term “jaw jerk” in in favour of less ambiguous terminology such as “jaw-closing” reflex or monosynaptic myotatic reflex potential (MSP; Widlam, 1976a and b). The jaw-closing reflex is considered a fundamental phenomenon of the facial and oropharyngeal areas (Dubner, Sessle and Stoery, 1978) as it utilises afferent and efferent components involved in the generation, learning and modulation of programmed jaw movement sequences. Thus the reflex would appear to form the basis of more complex functions such as mastication and swallowing (Sessle, 1981), although the response itself probably appears only infrequently in normal function. A downwards tap delivered to the chin in a relaxed human subject causes muscle stretch and this produces an afferent projection along group Ia and group II pathways (Figure:1) which in turn exert monsynaptic and polysynaptic influences on motoneurones in the trigeminal motor nucleus. Inter-segmental and suprasegmental projections onto alpha and fusimotoneurones located in this motor nucleus (Greenwood and Sessle, 1976; Sessle, 1977a and b) modulate ongoing motoneurone excitability thus influencing the mainifestation of evoked monosynaptic reflexes.

Thesis (M.S.)--University of Michigan, 1975.

Thesis (doctoral)--Münster, 1933. / Includes bibliographical references (p. 23-24).

Thesis (doctoral)--Münster, 1933. / Includes bibliographical references (p. 23-24).

Thesis (Ph. D.)--University of Adelaide, 2004. / Title from title screen. Description based on contents viewed Apr. 21, 2005. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1975.

Thesis (M.S.)--University of Michigan, 1949.