Temporalis myofascial flap in maxillofacial reconstruction: clinical and histological studies of the oral healing process

Objectives—To report our experience with temporalis myofascial flaps (TMF), describe the healing process of uncovered flaps in the mouth, and the histology of the repaired mucosa in the long term. Design—Prospective clinical and histological study. Subjects—36 patients who received a TMF over a 6.5 year period for serial assessment of the oral healing, 24 patients whose scars over the reconstructed area were assessed clinically, and 11 whose repaired mucosa was assessed histologically. Main outcome measures—To follow the clinical process of oral healing of the TMF and describe the repaired mucosa healed over the flap. Results—The uncovered TMF in the mouth healed gradually starting with an acute inflammatory phase, going through chronic inflammatory and proliferative phases with eventual epithelialisation of the oral mucosa. There were no major complications. The healed mucosa showed mild scarring in 70% of cases and the repaired mucosa had characteristic histological features that were distinct from the normal mucosa. Conclusion—The TMF is an extremely reliable and versatile flap for maxillofacial reconstruction which heals gradually with eventual coverage by mildly scarred repaired mucosa.     

Cephalometric errors: A comparison between repeat measurements and retaken radiographs

This study compares landmark location errors in cephalometric radiography (when re-measuring radiographs) and radiographic errors (when retaking the radiograph). The samples comprised 32 remeasured and re-digitized radiographs and a further series of 22 retaken radiographs drawn from the same overall sample of 12-year-old Chinese children in Hong Kong. All radiographs were recorded in natural head posture with the lips in light contact. The relative size of the errors were assessed by calculating the 'error percentage' for both selected dento-skeletal and soft tissue profile measures. It is suggested that this index is clinically more meaningful than the usually used 'method error'. It expresses the variance of the method error (me2) as a percentage of the variance of the measurement under study (standard deviation2). This error percentage was found to be doubled, on average, for measurements on the retaken radiographs. In general, measures with most landmarks in the mid-sagittal plane showed the least increase in percentage error. The results suggest that errors arising from retaking cephalometric radiographs may effectively be greater than those usually reported. The Frankfort plane, the functional occlusal plane and the incisor long axes displayed poor reproducibility. For the soft tissues the lips served as poor angular landmarks and relatively acute angles with short 'arms' also displayed large errors.     

Melanotic neuroectodermal tumour of infancy: an immunohistochemical and ultrastructural study

Two cases of melanotic neuro-ectodermal tumour of infancy (MNTI)—a rare neoplasm arising in the first year of life—are reported, with the results of immunohistochemical and ultrastructural examination. The tumours consisted of a biphasic cell population in a fibrous stroma. The small, darkly staining cells comprising the first population stained positively for synaptophysin, showing them to be neuroblasts, and the large epithelioid cells comprising the second cell population stained positively with the antibodies HMB-45 and NKI-Beteb, showing them to be melanocytes. Ultrastructural examination of the second case confirmed the biphasic nature of the tumour cells, with secretory granules and neurofilaments in the neuroblastic population, and melanosomes in the epithelioid population. These results add to the evidence supporting the neural crest origin of MNTI and confirm its formation from two distinct cell lines. Both cases have responded to local excision, with no recurrence more than a year after initial treatment.     

Local complications following intravenous benzodiazepines in the dorsum of the hand. A comparison between midazolam and Diazemuls in sedation for dentistry

Two hundred patients requiring sedation for minor oral surgery were randomly allocated to receive either midazolam or diazepam as Diazemuls intravenously through a 23-gauge indwelling needle in the dorsum of the hand. The site of injection was inspected at 7 days and 14 days post injection and assessed for pain, tenderness, redness, induration, painless thrombosis, and thrombophlebitis. The mean dose administered was 0.119 mg/kg of midazolam and 0.298 mg/kg of Diazemuls. At 7 days there was no significant difference in venous complications. At the 14 day follow up, the midazolam group had a significantly greater incidence of tenderness and redness (p less than 0.001 and p less than 0.05 respectively using Chi squared test). The incidence of thrombophlebitis in the midazolam group was 2% at 7 days and 1% at 14 days, the corresponding figures in those given Diazemuls being none and 1% respectively. We conclude that the dorsum of the hand is a satisfactory site of injection for administration of these drugs. The higher incidence of minor complications at 14 days following midazolam was offset by its more reliable amnesic properties.     

Long-term Clinical Performance of Resin-Bonded Fixed Partial Dentures Placed in a Developing Country

Purpose This study assesses the clinical performance of 92 resin-bonded fixed partial dentures (FPDs) placed at four private practices in Karachi, Pakistan, between 1982 and 1991. Materials and Methods The distribution of the FPDs was 9 perforated, 45 electrolytically etched, and 38 silicoated. Twenty-five FPDs replaced anterior teeth and 67 replaced posterior teeth. There were 66 FPDs with single pontics and 26 with multiple pontics. The perforated designs used a restorative composite for cementation, whereas the electrolytically etched and silicoated designs used a composite luting cement. The observation periods for the perforated, electrolytically etched, and silicoated FPDs were 114,99, and 30 months respectively. Results During the evaluation period, 27 FPDs (29%) failed; of these, 4 were perforated, 18 were electrolytically etched, and 5 were silicoated. The mean (±SD) duration of the successful clinical service for all FPDs was 41 ± 26 months. The mean time to failure for the FPDs that did not survive was 35 ± 23 months. The silicoated FPDs tended to have early failure, as did the FPDs with multiple pontics and those in the mandibular arch. Anterior and posterior FPDs performed equally well. Conclusions These findings, in conjunction with those from Europe and North American, show that resin-bonded FPD technology is as successful in a developing country as in industrialized areas of the world.     

Errors in mounting maxillary casts using face-bow records as a result of an anatomical variation

The relationship of the teeth to the intercondylar axis and horizontal plane is transferred to the articulator by means of a face-bow record. In most semi-adjustable articulators, the horizontal plane to which the maxillary cast is orientated is the Frankfort plane or its near equivalent, the orbital-axis plane. For this purpose the infraorbital notch is used as the anterior reference point Clinical observations of Cantonese patients suggest that in some individuals the Frankfort plane may not be horizontal, with the result that the orientation of the casts in the articulator is incorrect with respect to the horizontal plane, and a preliminary study has been undertaken to investigate this range of variation.

Lateral cephalometric radiographs were taken of 33 Cantonese male adult subjects in natural head posture. The cephalometric landmarks of the Frankfort plane were recorded relative to the true vertical axis and, by the use of a digitizer, fed into a computer for analysis. The results show that there is considerable individual variation in the orientation of the Frankfort plane. Variations ranging between +11° and -2° in relation to the horizontal were recorded. Large anatomical variations may make errors difficult to avoid when the manufacturers' recommended anterior reference point for a particular face-bow is the infraorbital notch. Clearly this is a source of potential error which should be recognized when treating this ethnic group.     

An animal model for maxillary reconstruction using a temporalis muscle flap

This article describes the feasibility of using the temporalis muscle flap to cover a defect after maxillectomy in cats and to evaluate the clinical healing process of this flap in the oral environment. The material consisted of 30 cats of the Felis catus species. A standardized unilateral maxillectomy was performed and the resulting defect immediately closed with a pedicled temporalis flap. The healing of this flap was clinically assessed at determined intervals. Healing of the temporalis flap in the oral environment of cats progressed from an inflammatory to a proliferative phase, with eventual coverage by a smooth oral mucosa 18 to 24 weeks after surgery. The cat proved to be a useful model for this type of study.     

The use of role-play and psychodrama in the education of the dental undergraduate

The delivery of effective information flow through self learning, critical thinking and problem solving is one of the objectives of current curriculum development within the Dental Faculty of the University of Hong Kong. These objectives reflect a desire to encourage skills related to 'comprehension learning' and 'meaning orientation' rather than 'rote' learning and 'surface' approaches. This paper explains the way in which role-play and psychodrama are used in an effort to achieve these objectives.