Buccal mucosa cell damage in individuals following dental X-ray examinations.

The aim of the present study was to monitor genotoxic and cytotoxic effect of X-ray on exfoliated buccal mucosa cells and investigate the association between the effects and the accumulated absorbed doses of oral mucosa. 98 participants' buccal mucosa cells were collected before and 10 days after different series of dental radiographs performed. Cytological preparations were successively dyed with the methods of Feulgen and fast-green, and analyzed under a light microscope.

[Histological changes in the circum-maxillary sutures during alternate maxillary expansions and constrictions in a rat model].

Objective: To investigate changes in the circum-maxillary sutures during alternate maxillary expansions and constrictions in a rat model.

Methods: Twenty-two male Sprague-Dawley rats (6 weeks old) were used and divided into three groups. In maxillary expansion (ME) group (n=9), an expander was activated for 5 d, and then sacrificed.

Comparative characterization of maxillary expansion and alternate maxillary expansions and constrictions in rats.

The purpose of this study was to evaluate whether the cranial and circumaxillary sutures react differently to maxillary expansion (ME) and alternate maxillary expansions and constrictions (Alt-MEC) in a rat model. Twenty-two male Sprague-Dawley rats (6 weeks old) were used and divided into three groups. In ME group (n=9), an expander was activated for 5 days.

[Influence of the mandibular second premolar extraction on the angulation of the mandibular third molar].

Objective: To compare the angular changes in the developing mandibular third molars in the mandibular second premolar extraction and non-extraction cases and to determine whether the mandibular second premolar extraction causes favorable rotational changes in the angulations of the developing mandibular third molars and benefits its later eruption.

Methods: Pretreatment and posttreatment panoramic radiographs were taken from 45 subjects who had been treated by the extraction of the mandibular second premolars and 48 subjects who had been treated without extraction. The horizontal reference plane was used to measure and compare the changes in the angulations of the developing mandibular third molars.

Craniofacial morphology of Chinese patients with bilateral temporomandibular joint osteoarthrosis.

Objective: To evaluate the morphological features of craniofacial structures in young patients affected by bilateral temporomandibular joint osteoarthrosis (TMJOA).

Methods: Forty-three males and 189 females aged 15 to 25 years who had lateral cephalograms and temporomandibular joint (TMJ) radiological examinations were included. They were classified into a TMJOA group and a control group, according to TMJ bony status.

[Temporomandibular joint osteoarthrosis in patients receiving orthodontic treatments: a clinical investigation].

Objective: To investigate the clinical characteristics of temporomandibular joint osteoarthrosis (TMJOA) in patients with malocclusion before orthodontic treatment and evaluate the radiographic changes of temporomandibular joint during treatment.

Methods: Complete clinical recordings of 10,032 patients referring to the Orthodontic Department of Peking University School and Hospital of Stomatology from January 1998 to December 2003 were reviewed in present study. Patients with a history of previous orthodontic treatment, jaw surgery, facial trauma or systemic diseases which could potentially involve temporomandibular joint were excluded.