Translation and psychometric properties of the Chinese (Mandarin) version of the Child Oral Health Impact Profile-Short Form 19 (COHIP-SF 19) for school-age children.

BACKGROUND: Although caries and malocclusion occur with a high prevalence in Chinese school-age children, there were no appropriate instrument to assess the oral health-related quality of life (OHRQoL) for this population. The aim of our study was to develop a Chinese (Mandarin) version of the Child Oral Health Impact Profile-Short Form 19 (COHIP-SF 19) and provide a preliminary test of its psychometric properties. METHODS: The Chinese version of COHIP-SF 19 was developed through a standard translation and back translation procedure. The psychometric properties of the instrument were tested among 644 school-age children in Beijing, China, including the internal consistency, test-retest reliability, discriminant and convergent validity. A Mann-Whitney U test was used to determine the capability of the instrument to differentiate children with different caries and malocclusion outcomes. And partial Spearman correlations were used to determine the relationships between the OHRQoL scores and clinical-severity indicators and self-perceived health ratings, respectively. RESULTS: Chinese school-age children had relatively high OHRQoL scores, in spite of the fact that oral impacts were quite common (56.3%). The internal consistency and retest reliability were good to excellent with a Chronbach's alpha of 0.81 and an intra-class correlation coefficient (ICC) of 0.77. Children who had active tooth decay or severe malocclusion had significantly lower COHIP-SF 19 scores (P ≤0.001). Girls had somewhat higher scores in the oral health and functional well-being subscales (P <0.05), while children from rural districts had lower scores than children from urban areas (P <0.05). We observed a low to moderate correlation between the overall COHIP-SF 19, subscale scores and clinical severity indicators as well as self-perceived health ratings, after adjustment for children's age, gender, and school district (│r s │ =0.11 - 0.51, P <0.05). CONCLUSION: We confirmed satisfactory psychometric properties for the Chinese version of COHIP-SF 19 in a community sample of Chinese school-age children. The OHRQoL instrument should play a more important role in future clinical studies, epidemiological surveys and potential public health policy in China.

[Studies on keratocystic odontogenic tumors].

Keratocystic odontogenic tumors (KCOTs, previously known as odontogenic keratocysts) are aggressive, noninflammatory jaw lesions with a putative high growth potential and a propensity for recurrence. This article puts together a summary of the serial studies related to KCOTs undertaken by the author's research group in recent years. Intraosseous jaw cysts with a solely orthokeratinized lining epithelium have been suggested to differ from the typical KCOTs. We report 20 cases of such cyst type under the term of 'orthokeratinized odontogenic cyst (OOC)'. Apart from the presence of a keratinizing epithelial lining, the OOC lacks the other histological features of KCOT, exhibits little if any tendency to recur, has no apparent association with NBCCS, may be cured by simple enucleation, and may thus constitute its own clinical entity. Mutations in PTCH1 gene are responsible for NBCCS and are related in tumors associated with this syndrome. We have so far detected 26 PTCH1 mutations (2 mutations occurred twice) in 10 out of 34 (29.4%) sporadic and 14 out of 16 (87.5%) NBCCS-associated KCOTs. The 26 mutations consisted of 10 frameshift, 2 nonsense, 3 aberrant splicing, 4 in-frame insertion/deletion/ duplication and 7 missense mutations. Two missense mutations in PTCH2 were also detected in 2 out of 15 NBCCS related KCOT patients. By contrast, no pathogenic mutation was detected in SMO. Thus, our data, together with reports from other groups, indicate that defects of PTCH1 are involved in the pathogenesis of syndromic as well as sporadic KCOTs. The pathogenic role of PTCH2 requires further investigation. A series of in vitro studies on bone resorption of KCOTs and ameloblastomas were undertaken by this group. The results indicate that odontogenic lesions could promote bone resorption in vitro and it is likely to be related to some of the cytokines secreted by the lesions.

[PTCH gene mutations in odontogenic keratocysts].

OBJECTIVE: To investigate the frequency, type and distribution of PTCH mutations in odontogenic keratocysts (OKC) and to analyze the molecular pathological relationship between sporadic OKC and OKC associated with nevoid basal cell carcinoma syndrome (NBCCS). METHODS: Genomic DNA was extracted from 8 cases of OKC lesions (4 sporadic OKCs and 4 NBCCS-related OKCs). PTCH gene mutations were detected by PCR-direct sequencing. RESULTS: Six novel PTCH mutations were identified in 6 out of 8 cases (2 sporadic and 4 NBCCS-related OKCs). Two of these were missense mutations leading to substitution of an amino acid residue respectively. The other 4 mutations were identified as insertion or deletion ranging from one single base to 7 bases, three of which caused frame-shift leading to premature truncation of PTCH protein and one resulted in an insertion of 2 amino acid residues. All these identified mutations were novel and have not been previously described. CONCLUSIONS: PTCH gene mutation is a common event in NBCCS-related OKCs and could also be detected in some sporadic OKCs. Abnormalities of PTCH gene may be involved in the pathogenesis of OKC.