A randomized clinical trial to compare the Goshgarian and Nance palatal arch.

The aim of this trial was to evaluate whether a Nance or Goshgarian palatal arch was most effective for prevention of mesial drift, distal tipping, prevention of mesio-palatal rotation of the upper first permanent molars, and patient comfort and ease of removal. Patients were recruited from a district general hospital and a specialist orthodontic practice and randomly allocated to a Goshgarian (n = 29) or a Nance (n = 28) group. Pre-treatment study models (T1) were taken followed by the placement of the palatal arch, premolar extractions, and upper and lower fixed appliances. The clinical end point was 6 months (T2), at which time, an impression for an upper study model was taken. The amount of upper first permanent molar mesial movement, distal tipping, and mesio-palatal rotation was measured by scanning T1 and T2 study models and then using a software program to calculate molar changes. In addition, the patients recorded their discomfort scores using a seven-point Likert scale at each recall visit. Forty-nine patients (86 per cent) completed the trial. t-tests were used to compare molar movements between the Goshgarian and Nance palatal arch groups. There were no statistically significant differences between the palatal arches in terms of prevention of mesial drift or distal tipping (P > 0.05). There was a statistically significant difference in the amount of molar rotation between the arch types, with both exhibiting some disto-palatal rotation even though they were not activated for this movement. The Goshgarian palatal arch produced marginally more disto-palatal rotation than the Nance arch (P = 0.02), although this may not be considered clinically significant. A Mann-Whitney test revealed that there was also a statistically significant difference in pain scores between the Goshgarian and the Nance arch, with the latter being associated with more discomfort (P = 0.001). This trial did not support any preference in the use of the Goshgarian or Nance palatal arch, unless the slightly reduced patient discomfort with the Goshgarian arch is considered significant.

Polymorphous low-grade adenocarcinoma--a rare and aggressive entity in adolescence.

Polymorphous low-grade adenocarcinoma (PLGA) is an uncommon tumour that usually affects the minor salivary glands, particularly in the palate. It is rare in young patients, and here we report a case in a teenage girl. She presented at the age of 16, although the lesion had been noticed 2 years previously. The tumour showed histopathological features of PLGA, but recurred locally, behaved aggressively, and ultimately metastasised to cervical lymph nodes. This was accompanied by an altered histological picture, with a papillary cystic pattern and necrosis becoming progressively more prominent. PLGA is not always a low-grade lesion and some tumours, notably those with a papillary cystic growth pattern, may require more aggressive treatment.

Radiographic factors affecting the management of impacted upper permanent canines.

The aim of the investigation was to evaluate which radiographic factors influenced the orthodontists' decision whether to expose or remove an impacted upper permanent canine and was a retrospective, cross-sectional design. The sample consisted of all radiographic records of patients referred to the Orthodontic Department at Manchester University Dental Hospital with impacted upper permanent canines between 1994-1998 (n = 44). The following canine position measurements were made from the OPG: angulation to the midline, vertical height, antero-posterior position of the root, overlap of the adjacent incisor, and presence of root resorption of adjacent incisor(s). The labio-palatal position of the impacted canine was assessed from the lateral skull radiograph. Whether the impacted canine had been exposed and orthodontically aligned or removed was also recorded. Stepwise logistic regression analysis showed that the labio-palatal position of the crown influenced the treatment decision, with palatally positioned impacted canines more likely to be surgically exposed and those in the line of the arch, or labially situated, removed (P < 0.05). Additionally, as the canine angulation to the midline increased, the canine was more likely to be removed (P < 0.05). The orthodontists' decision to expose or remove an impacted upper permanent canine, based on radiographic information, seems to be primarily guided by two factors: labio-palatal crown position and angulation to the midline.