Biomedical subjects

M N Chau

Publications and source records attributed to M N Chau.

7 recordsLinked to original sources

PubMed1995

The reproducibility and repeatability of the Wits analysis.

Since the introduction of the Wits analysis, the validity of the method has been questioned, as the functional occlusal plane in particular has been cited as a major source of error. This may be either subjectively placed or defined by existing cephalometric methods. A study is therefore reported of the repeatability (intraobserver comparison) and reproducibility (interobserver comparison) of the Wits assessment on the basis of a double series of tracings by each of two observers. No statistically significant difference was found for the repeatability of distance AO-BO by either observer, but interobserver repeatability was less satisfactory, and the mean values varied by approximately 75%. It was also found that the highest single error between two series of tracings was 3.1 mm (observer A) and 5.8 mm (observer B).

Adolescent↗

PubMed1993

Inter- and intra-observer identification of landmarks used in the Delaire analysis.

The investigation of intra- and inter-observer tracing error of points S, N, ANS, A, B, Me, Go, and Ba (conventional cephalometric points) and some of the landmarks used in the Delaire analysis (FM, M, CT, Clp, and Br) shows that a high level of intra-observer repeatability was achieved for each landmark, and that no statistically significant differences occurred. Also there were no statistically significant differences on inter-observer comparison of averaged values for the replicate tracings of each observer. However, the gross error which may occur in an individual case may be of considerable clinical significance.

Adolescent↗

PubMed1989

A clinical-pathological study of 53 intra-oral pleomorphic adenomas.

Conflict exists with respect to the type of pleomorphic adenoma (PA) most likely to recur and whether the possibility of recurrence can be determined by the histology of the lesion. In this study, specific clinical, histological features and treatment modalities were examined in 53 intra-oral PA's with respect to their relevance to the diagnosis and prognosis. No correlation was found between the duration of symptoms and the proportion of stroma in the PA's nor was there any correlation between the size and the duration. However, at the time of diagnosis, the stroma-poor tumours had attained a significantly larger size than the stroma-rich tumours. This may suggest that the cellular tumours grow at a faster rate. Hyaline cells were shown to be a distinct feature of intra-oral PA's, especially in the stroma-poor subtypes. The proportion of the stroma and the capsule integrity do not seem to influence the prognosis. Follow-up information was obtained for 51% of the patients, and despite the fact that the majority of the lesions (33/53) were treated by excisional biopsy, no recurrences were reported. The follow-up period ranged from 0.6 to 12.6 years (mean 5.3 years).

Adenoma, Pleomorphic↗

PubMed1989

Traumatic neuroma following sagittal mandibular osteotomy.

A case of painful traumatic neuroma, arising from the inferior alveolar nerve after sagittal osteotomy of the mandible with demonstrable radiological change, is reported. The co-existence of temporomandibular joint (TMJ) pain-dysfunction syndrome and a painful traumatic neuroma had posed diagnostic problems. Some modifications of the surgical technique are discussed with a view to minimizing damage to the inferior alveolar nerve during sagittal osteotomy of the mandible. The aetiology, clinical features, diagnosis and treatment of traumatic neuromas are reviewed.

Adult↗

PubMed1986

Intra-oral benign solid oncocytoma.

Oncocytomas are extremely uncommon in the intra-oral minor salivary glands, they are rarely reported in the literature and the histopathology and clinical details are inadequately documented. This has led to uncertainty with regard to the behaviour and prognosis of this type of lesion. A case of benign solid oncocytoma arising from intra-oral minor salivary glands is reported here with a brief review of the pertinent literature.

Adenoma↗

PubMed1986

Intra-oral salivary gland neoplasms: a retrospective study of 98 cases.

The findings of a retrospective study of 98 minor salivary neoplasms are reported. The patient's ages ranged from 13-79 years and there was an equal sex distribution. Sixty-one of the lesions were benign, 53 being pleomorphic adenomas and 8 monomorphic adenomas. Of the malignant tumors, 19 were muco-epidermoid tumors, 12 adenoid cystic carcinomas, 4 adenocarcinomas, 1 carcinoma ex-pleomorphic adenoma and 1 epidermoid carcinoma. One striking finding was the difference in age at the time of presentation for patients with muco-epidermoid tumors compared with those with adenoid cystic carcinomas. Seventy-four percent of the patients with muco-epidermoid tumors were under 50 years of age, but 75% of those with adenoid cystic carcinomas were over 50 years.

Adenoma, Pleomorphic↗

PubMed1984

Oral warty dyskeratoma.

Warty dyskeratoma (WD) is a benign solitary lesion of unknown aetiology affecting the skin and oral mucosa. The profound dyskeratotic changes may mimic invasive squamous cell carcinoma. Two cases of oral WD, which were originally diagnosed as early squamous cell carcinoma, are presented. The clinical features, histopathology and aetiology are reviewed together with other reports in the literature. These 2 cases have been followed for 14 and 6 years respectively and they are the longest follow-up periods reported in the literature in English. The lesions have not recurred.

Diagnosis, Differential↗