Recommendations for treating stage I-III periodontitis in the Taiwanese population: A consensus report from the Taiwan Academy of Periodontology.

BACKGROUND/PURPOSE: Based on the fundamental of the S3-level clinical practice guideline (CPG) for treating stage I-III periodontitis developed by the European Federation of Periodontology (EFP), this consensus report aimed to develop treatment recommendations for treating periodontitis in the Taiwanese population. METHODS: The report was constructed by experts from the Taiwan Academy of Periodontology. The following topics were reviewed: (a) the prevalence of periodontitis in Asia and current status of treatment in Taiwan; (b) specific anatomical considerations for treating periodontitis in Asians; (d) educational and preventive interventions and supragingival plaque control; (d) subgingival instrumentation and adjunctive treatment; (e) surgical periodontal therapy; and (f) maintenance and supportive periodontal care. Recommendations were made according to the evidences from the EFP CPG, the published literature and clinical studies in Asians, and the expert opinions. RESULTS: The treatment recommendations for the Taiwanese population were generally in parallel with the EFP CPG, and extra cautions during treatment and maintenance phases were advised due to the anatomical variations, such as shorter root trunk, higher prevalence of supernumerary distolingual root and lingual bony concavity in mandibular posteriors, and thinner anterior labial plate, of the Asian population. CONCLUSION: The EFP CPG could be adopted for treating periodontitis and maintaining periodontal health of the Taiwanese population, and anatomical variations should be cautious when the treatment is delivered.

Long-term sequential receptor activator of NF-κB ligand (RANKL) and osteoprotegrin (OPG) expression in lipopolysaccharide-induced rat periapical lesions.

BACKGROUND: Long-term sequential expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegrin (OPG) in lipopolysaccharide (LPS)-induced rat periapical lesions has not been studied. MATERIALS: Seventy-two 4-week-old Wistar rats were divided into eight experimental groups and one control group (eight animals in each). METHODS: Lipopolysaccharide-induced periapical lesions were produced in rats by occlusal exposure of the pulp of their lower first molars in all experimental groups but not the control group. The extent of periapical destruction was measured by radiographic imaging. RANKL and OPG mRNA were measured in all tissue sections containing the periapical lesions as well as the control group every week from week 1 to week 8 by real-time quantitative reverse transcription polymerase chain reaction. RANKL and OPG protein were determined by immunohistochemistry. Osteoclasts were identified by enzyme histochemistry. RESULTS: The sequential changes in the mRNA and protein expression of RANKL and OPG were largely compatible with the occurrence of osteoclasts histologically and enzymes histochemically, as well as the mean areas of the periapical lesions radiographically during long-term observation of the LPS-induced rat periapical lesions. CONCLUSION: This study may be the first to demonstrate the long-term RANKL and OPG expression every week from week 1 to week 8 using LPS to produce periapical infection in a Wistar rat model. The long-term findings of high expressions of RANKL and OPG further extend the potential application of the Wistar rat model for future experimental trials using RANKL inhibitor to evaluate the treatment outcome for LPS-induced rat periapical lesions.

MMP-8 -799 C>T genetic polymorphism is associated with the susceptibility to chronic and aggressive periodontitis in Taiwanese.

AIM: Matrix metalloproteinase (MMP)-8 is a protease that degrades numerous extracellular molecules and has been implicated in the pathogenesis of periodontitis. Polymorphism in the MMP-8 could affect the susceptibility to disease. Our aim was to evaluate the association between periodontitis and MMP-8 -799 C>T polymorphism. MATERIAL AND METHODS: Genomic DNA was obtained from 361 chronic periodontitis patients (CP), 96 aggressive periodontitis patients (AgP), and 106 periodontally healthy controls (HC). MMP-8 -799 C>T polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The frequencies of genotypes in diseased groups were similar but were significantly different from those in the HC. Multivariate logistic regression analysis with adjustment for age, gender and smoking indicated that increased risks of AgP and CP were associated with the -799 T allele (in AgP, adjusted OR = 1.99, p = 0.04; in CP, adjusted OR = 1.87, p = 0.007). To avoid the confounded effect of smoking on MMP-8 polymorphism to periodontitis, the analysis was conducted on non-smokers and the associations were significant. CONCLUSIONS: These results suggested that non-smoking Taiwanese with the MMP-8 -799 T allele were associated with the risks of both CP and AgP. Further studies in other ethnic populations are necessary.

Polymorphisms in the apoptosis-associated genes FAS and FASL and risk of oral cancer and malignant potential of oral premalignant lesions in a Taiwanese population.

BACKGROUND: Our aim was to measure the relationship of FAS (-1377G>A and -670A>G), FASL (-844C>T) gene variants and risk of oral cancer. METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used to determine the FAS and FASL polymorphisms in 294 oral squamous cell carcinoma (OSCC), 53 oral submucous fibrosis (OSF), and 84 oral leukoplakia (OL) patients, as well as in 333 healthy controls. A standardized questionnaire was applied to collect demographic data, and potential confounding factors. JMP statistical software was used to analyze the association. RESULTS: FAS and FASL polymorphisms were not correlated with OSCC development or the malignant potential of OL by simple and multivariate logistic regression. However, a two- to fourfold difference in the risks of betel quid chewing, alcohol consumption, and smoking on OSCC development were observed between participants with different FAS polymorphisms. FAS polymorphisms were significantly correlated with the malignant potential of OSF. Multivariate logistic regression analysis indicated that FAS A(-1377)-G(-670) vs. G(-1377)-A(-670) haplotype (OR = 2.26, 95% CI = 1.16-4.41) was correlated with the malignant potential of OSF. CONCLUSIONS: We suggest that FAS and FASL polymorphisms are not significantly correlated with OSCC development or malignant potential of OL. The impact of substance usage on OSCC development could be differentiated by FAS polymorphisms. FAS A(-1377)-G(-670) haplotype may play a role in the malignant potential of OSF.

The association of Fcgamma receptor IIIb genetic polymorphism and susceptibility to periodontitis in Taiwanese individuals.

AIM: The allelic polymorphism of FcgammaRIIIb, the neutrophil-specific receptor involved in the phagocytosis of immunoglobulin G-opsonized bacteria, has functionally distinct capacities that are important in host defence mediated by neutrophils. The aim of this study was to identify whether the polymorphism of FcgammaRIIIb is associated with periodontitis in Taiwanese individuals. MATERIALS AND METHODS: This case-control study included of 93 aggressive periodontitis (AgP) patients, 372 chronic periodontitis (CP) patients and 158 healthy controls (HC). The FcgammaRIIIb genotypes were determined by PCR using allele-specific primers. The risk for periodontitis associated with genotypes was calculated as the odds ratio (OR). RESULTS: A significant difference was observed in the distribution of the FcgammaRIIIb genotype between either AgP and HC, or AgP and CP, but not between CP and HC. The OR for carriage of the NA2 allele (NA1NA2+NA2NA2 versus NA1NA1) in AgP was 3.27 [95% confidence interval (CI)=1.57-7.51, p=0.0027] and 2.94 (95% CI=1.49-6.48, p=0.0037), as compared with HC and CP. After adjusting for possible confounding factors, the association was still significant. CONCLUSIONS: The results of the present study suggest that subjects carrying at least one copy of the FcgammaRIIIb-NA2 allele might be associated with susceptibility to AgP. However, the clinical implications of the FcgammaRIIIb allelic polymorphism should be determined by further studies.

Polymorphisms of COX-2 -765G>C and p53 codon 72 and risks of oral squamous cell carcinoma in a Taiwan population.

The association between polymorphisms of COX-2 -765G>C and p53 codon 72, and oral squamous cell carcinoma (OSCC) remains unclear. We investigated the associations between COX-2 and p53 polymorphisms, oral precancerous lesions (OPL), and OSCC. Demographic data and substance use (smoking, drinking, and betel quid chewing) data were collected from 297 patients with OSCC, 70 with oral leukoplakia (OL), 39 with oral submucosal fibrosis (OSF), and 280 healthy controls. COX-2 and p53 polymorphisms were determined by PCR-RFLP methods. A significantly higher proportion of OSCC and OPL patients were male, and frequent habitual users of the three substances. No association was found between p53 and COX-2 polymorphisms, ethnicity, and gender. Polymorphisms of p53 were not associated with OSCC development and malignant potential of OPL, OSF, and OL. The frequency of COX-2 -765G/G genotype was significantly higher in healthy controls (chi(2)=93.83, p<0.0001). After adjusting for possible confounding factors, COX-2 -765C allele vs. -765G/G genotype (OR=0.22, 95%CI=0.12-0.39) was a protective factor against OSCC development, but was a risk factor for malignant potential of OSF (OR=3.20, 95%CI=1.32-8.94) and OL (OR=6.73, 95%CI=2.84-19.87). We suggest that COX-2 -765G>C polymorphisms play a different role in OSCC development than in malignant potential of OSF and OL. However, p53 codon 72 polymorphisms show no such correlation.

Cyclooxygenase-2 Gene-765 single nucleotide polymorphism as a protective factor against periodontitis in Taiwanese.

AIM: Prostaglandin E(2) (PGE(2)) is considered to be an important mediator of tissue destruction in periodontitis. The cyclooxygenase (COX) catalyses the production of PGs. COX-2, which is induced in an inflammatory response, is responsible for PGs synthesis at sites of inflammation. A single nucleotide polymorphism of COX-2(-765) has been shown to alter the expression of the COX-2 gene. The purpose of the present study was to evaluate the association of the COX-2(-765) polymorphism and susceptibility to periodontitis in Taiwanese. MATERIAL AND METHODS: Eighty-five cases of aggressive periodontitis (AgP), 343 cases of chronic periodontitis (CP) and 153 cases of healthy controls (HC) were recruited for the study. Genotypes of COX-2(-765) were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The distribution of genotypes among groups was compared by logistic regression analyses. The risk for periodontitis associated with genotypes was calculated as the odds ratio (OR). RESULTS: The prevalence of the GC and CC genotypes was significantly lower in AgP (5%) and in CP (29%) compared with the HC (42%). The ORs for carriage of the -765C allele (GC+CC versus GG) in AgP and CP were 0.068 (95% CI=0.020-0.173, p<0.0001) and 0.571 (95% CI=0.385-0.849, p=0.006), respectively. After adjustment for age, gender and smoking status, the OR was 0.071 (95% CI=0.017-0.219) and 0.552 (95% CI=0.367-0.829) for AgP and CP, respectively. CONCLUSIONS: The results of the study suggest that the -765G to C polymorphism of the COX-2 gene is associated with a decreased risk for periodontitis in Taiwanese, especially in AgP. However, the biological meaning needs further investigation.

Endodontic shaping performance using nickel-titanium hand and motor ProTaper systems by novice dental students.

BACKGROUND/PURPOSE: Preparing a continuous tapering conical shape and maintaining the original shape of a canal are obligatory in root canal preparation. The purpose of this study was to compare the shaping performance in simulated curved canal resin blocks of the same novice dental students using hand-prepared and engine-driven nickel-titanium (NiTi) rotary ProTaper instruments in an endodontic laboratory class. METHODS: Twenty-three fourth-year dental students attending China Medical University Dental School prepared 46 simulated curved canals in resin blocks with two types of NiTi rotary systems: hand and motor ProTaper files. Composite images were prepared for estimation. Material removed, canal width and canal deviation were measured at five levels in the apical 4 mm of the simulated curved canals using AutoCAD 2004 software. Data were analyzed using Wilcoxon's rank-sum test. RESULTS: The hand ProTaper group cut significantly wider than the motor rotary ProTaper group in the outer wall, except for the apical 0 mm point. The total canal width was cut significantly larger in the hand group than in the motor group. There was no significant difference between the two groups in centering canal shape, except at the 3 mm level. CONCLUSION: These findings show that the novice students prepared the simulated curved canal that deviated more outwardly from apical 1 mm to 4 mm using the hand ProTaper. The ability to maintain the original curvature was better in the motor rotary ProTaper group than in the hand ProTaper group. Undergraduate students, if following the preparation sequence carefully, could successfully perform canal shaping by motor ProTaper files and achieve better root canal geometry than by using hand ProTaper files within the same teaching and practicing sessions.

Aggregatibacter (Actinobacillus) actimycetemcomitans leukotoxin and human periodontitis - A historic review with emphasis on JP2.

Aggregatibacter (Actinobacillus) actimycetemcomitans (Aa) is a gram-negative bacterium that colonizes the human oral cavity and is causative agent for localized aggressive (juvenile) periodontitis (AgP). In the middle of 1990s, a specific JP2 clone of belonging to the cluster of serotype b strains of Aa with highly leukotoxicity (leukotoxin, LtxA) able to kill human immune cells was isolated. JP2 clone of Aa was strongly associated with in particularly in rapidly progressing forms of aggressive periodontitis. The JP2 clone of Aa is transmitted through close contacts. Therefore, AgP patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontitis lesions are relatively high. Furthermore, timely periodontal treatment, including periodontal surgery supplemented by the use of antibiotics, is warranted. More importantly, periodontal attachment loss should be prevented by early detection of the JP2 clone of Aa by microbial diagnosis testing and/or preventive means.

Prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan.

BACKGROUND: In Taiwan, a distinct ethnic group variation in incidence and mortality rates has been suggested for most carcinomas. Our aim is to identify the role of prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan. METHODS: Taiwan Cancer Registry records of 9039 subjects diagnosed with oral and pharyngeal carcinoma were analyzed. The population was divided into three ethnic groups by residence, which were Taiwanese aborigines, Hakka and Hokkien communities. Five-year survival rates were estimated by Kaplan-Meier methods. Ethnic curves differed significantly by log-rank test; therefore separate models for Taiwanese aborigines, Hakka and Hokkien were carried out. The Cox multivariate proportional hazards model was used to examine the role of prognostic factors on ethnic survival. RESULTS: The five-year survival rates of oral and pharyngeal carcinoma were significantly poorer for Hokkien community (53.9%) and Taiwanese aborigines community (58.1%) compared with Hakka community (60.5%). The adjusted hazard ratio of Taiwanese aborigines versus Hakka was 1.07 (95%CI, 0.86-1.33) for oral and pharyngeal carcinoma mortality, and 1.16 (95%CI, 1.01-1.33) for Hokkien versus Hakka. Males had significantly poor prognosis than females. Subjects with tongue and/or mouth carcinoma presented the worst prognosis, whereas lip carcinoma had the best prognosis. Subjects with verrucous carcinoma had better survival than squamous cell carcinoma. Prognosis was the worst in elderly subjects, and subjects who underwent surgery had the highest survival rate. CONCLUSION: Our study presented that predictive variables in oral and pharyngeal carcinoma survival have been: ethnic groups, period of diagnosis, gender, diagnostic age, anatomic site, morphologic type, and therapy.

Prevalence of three-rooted mandibular first molars among Taiwanese individuals.

The purpose of this study was to evaluate the prevalence of mandibular first molars featuring a distolingual root among a Taiwanese population. A total of 731 patients' periapical radiographs were screened and examined to obtain 166 samples for this study. The gender, symmetry, and frequencies of occurrence of three-rooted mandibular first molars were recorded. The prevalence of three-rooted mandibular first molars was 21.09%. The bilateral incidence of a symmetrical distribution was 68.57%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence. Clinicians should be aware of the high racial prevalence of the distolingual root in mandibular first molars among the Taiwanese (Chinese) population before initiating endodontic treatment.

Changes in gingival crevicular fluid interleukin-4 and interferon-gamma in patients with chronic periodontitis before and after periodontal initial therapy.

Cytokines are pivotal to the immune response of chronic periodontitis. The present study investigated the changes of gingival crevicular fluid (GCF) interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) in patients with chronic periodontitis before and after initial nonsurgical periodontal therapy (NSPT). GCF was collected from 17 patients by means of Periopaper at baseline and 1 month after NSPT. IL-4 and IFN-gamma were measured by enzyme-linked immunoabsorbent assay. NSPT resulted in decreased total amount of IFN-gamma, increased concentration of IL-4, and increased ratio of IL-4 to IFN-gamma levels. We suggest that a low ratio of IL-4 to IFN-gamma levels might be involved in the destruction (diseased sites) of periodontal tissue, whereas an increased ratio of IL-4 to IFN-gamma levels could be related to the improvement of clinical periodontal health.

Association of vitamin D receptor gene polymorphisms and periodontitis in a Taiwanese Han population.

BACKGROUND/PURPOSE: : Genetic polymorphisms in the vitamin D receptor (VDR) gene are related to the immune response and bone metabolism, both of which are implicated in the pathogenesis of periodontitis. This study was to investigate the association between VDR-gene polymorphisms and periodontitis among a Taiwanese Han ethnic population. MATERIALS AND METHODS: Ninety-two aggressive periodontitis (AgP), 385 chronic periodontitis (CP) and 163 healthy controls (HC) were recruited from dental clinics. Demographic characteristics and possible confounding factors were obtained using a self-reported questionnaire. The VDR rs731236 (TaqI), rs7975232 (ApaI), rs1544410 (BsmI), and rs2228570 (FokI) polymorphisms were genotyped using PCR-RFLP methods. Statistical analyses were applied to determine the associations. RESULTS: The individual VDR polymorphisms were not associated with risk of AgP and CP. The f allele of rs2228570 was related to decreased risk for AgP. Subjects with TAbF (adjusted OR = 7.2, 95% CI = 3.2-7.2, p < 0.0001) or TAbf (adjusted OR = 0.17, 95% CI = 0.05-0.48, p = 0.002) combined polymorphisms were significantly associated with AgP. Subjects with Tabf (adjusted OR = 2.6, 95% CI = 1.8-3.8, p < 0.0001), TAbF (adjusted OR = 4.4, 95% CI = 2.6-8.1, p < 0.0001), TabF (adjusted OR = 0.36, 95% CI = 0.2-0.5, p < 0.0001), or TAbf (adjusted OR = 0.45, 95% CI = 0.3-0.7, p = 0.001) combined polymorphisms were significantly associated with CP. CONCLUSION: The study indicates that VDR gene polymorphisms are associated with AgP and CP in a Taiwanese Han population.

Ingredients contribute to variation in production of reactive oxygen species by areca quid.

Areca quid (AQ) chewing has been implicated an independent risk factor for the development of oral cancer. Taiwanese areca quid (AQ) refers to a combination of areca nut (AN), lime, and inflorescence of Piper betle Linn. (IPB) or Piper betle leaf (PBL). Studies of AQ in other countries reported that AN extract combined with lime generates reactive oxygen species (ROS), such as hydroxyl radical (HO.), known to be a contributing factor in oral mucosa damage. To determine whether HO. is formed in the oral cavity during AQ chewing, the formation of meta-tyrosine (m-Tyr) and ortho-tyrosine (o-Tyr) from l-phenylalanine (Phe) was confirmed. It was demonstrated that combined aqueous extracts of AN, lime, metal ions (such as Cu2+ and Fe2+), and IPB or PBL produced HO.. Thus, the yield of HO. significantly increases when higher amounts of IPB or lime are added and also when Cu2+ and Fe2+ are increased. Further, the omission of any one of these ingredients significantly reduces the formation of HO.. Our results found that chewing AQ with IPB generated significantly higher HO. than chewing AQ with PBL, and may result in greater oxidative damage to the surrounding oral mucosa.

Factors associated with quitting areca (betel) quid chewing.

OBJECTIVES: The purpose of this study was to provide useful data for a future abstinence project by identifying the factors related to quitting areca (betel) quid chewing. METHODS: The study was cross-sectional. Data on demographic variables, psychological factors and substance-use behaviors were collected via questionnaires from 326 participants. RESULTS: Multiple logistic regression analysis indicated that the areca/betel quid chewers who were less educated (OR = 0.58, 95% CI = 0.34-0.98) were least likely to try to give up. Among the chewers who tried to quit, those employed as full-time drivers (OR = 2.24, 95% CI = 1.14-4.39), who had drinking habits (OR = 2.41, 95% CI = 1.24-4.66), and who preferred to chew only betel quid wrapped with leaf (OR = 4.44, 95% CI = 1.99-9.90) were more likely to fail. Chewers who successfully quit had a higher internal health locus of control compared with those who failed to quit (one-point increments, OR = 0.94, 95% CI = 0.90-0.98). CONCLUSIONS: The results suggest that health educators and researchers can better influence people's chewing behavior if the importance of chewers' education level, job type, substance use (i.e. drinking habits, type of betel quid), and level of health locus of control are all taken into consideration when devising interventions.

Reducing, by pulse width modulation, the curing temperature of a prototype high-power LED light curing unit.

Third-generation LEDs have high irradiance and efficiency, but the associated temperature rise is potentially hazardous to the pulp of teeth. We evaluated, during composite polymerization, the irradiance and temperature rise of a prototype high-power LED light curing unit (LCU) with optimal pulse width modulation (PWM), and then compared the results with four off-the-shelf high-power LCUs. A cavity was prepared in a tooth, and a composite resin layer was applied and cured. For each LCU, the irradiance and temperature changes at the pulp-dentin junction were measured. Microhardness (Vickers hardness) of cured composite samples was measured for each LCU. Our prototype had a final temperature of 36.4 +/- 1.3 degrees C and irradiance of 1,182 +/- 1 mW/cm2. The unit with the highest temperature had a temperature of 48.7 +/- 1.2 degrees C and an irradiance of 1,194 +/- 1 mW/cm2. Based on the results of the present study, it was shown that PWM technology reduced the curing temperature while retaining the polymerization effectiveness of a high-power LED LCU.

Matrix metalloproteinase-2, -9, and tissue inhibitor of MMP-2 gene polymorphisms in Taiwanese periodontitis patients.

BACKGROUND/PURPOSE: Matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs (TIMPs) have been shown to play an important role in the pathogenesis of tissue destruction in periodontitis. The associations between single nucleotide polymorphisms (SNPs) in the promoter regions of MMP-2, MMP-9, and TIMP-2 genes and the risk of aggressive periodontitis (AgP) and chronic periodontitis (CP) were investigated in a Taiwanese population. MATERIALS AND METHODS: MMP-2 C-1306T, C-735T, T-790G, and MMP-9 C-1562T and TIMP-2 G-418C SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis in 69 patients and 129 patients with AgP and CP, respectively, and 117 periodontal healthy individuals who served as healthy controls (HC). Chi-square test and logistic regression analysis were used to investigate the possible association of genotypes with periodontitis. RESULTS: No significant differences in the distributions of the C-1306T and C-735T variants between periodontitis and HC were detected. Patients with genotype of MMP-2 -790 TT or T allele of MMP-2-790T/G as compared to genotypes of GT + GG genotypes or G allele, were less susceptible to CP [odds ratio (OR) = 0.50, 95% confidence interval (CI) = 0.25-1.00 and OR = 0.52, 95% CI = 0.28-0.96, respectively]. The frequencies of TIMP-2 G-418C gene polymorphisms in nonsmokers were statistically significantly different among AgP, CP, and HC groups (P = 0.024). The nonalcohol drinking participants with C allele of MMP-9 C-1562T as compared to T allele, were less susceptible to AgP (adjusted OR = 0.4; 95% CI, 0.18-0.90). CONCLUSION: It is suggested that MMP-2 T-790G, MMP-9 C-1562T, and TIMP-2 G-418C gene polymorphisms might be associated with periodontitis in the Taiwanese Han population.

Topographic study of root trunk type on Chinese molars with Class III furcation involvements: molar type and furcation site.

This study investigated the relationship between root trunk length and prognosis for molars with furcation involvement. Molars with furcation involvement were obtained from 169 patients affected with periodontitis. The test group consisted of 174 hopeless molars screened from a total of 441 molars with Class III involvement; the remaining 267 molars formed the control group. Both arches showed a significantly higher missing rate for teeth with a long root trunk length (type C) in second molars (41.3% and 32.4% in the maxilla and mandible, respectively), with a high degree of Class III furcation involvement for the test group (extracted hopeless or poor prognosis), compared to first molars (9.9% and 0.9% in the maxilla and mandible, respectively). Both arches had a significantly higher prevalence of long root trunk lengths in the second molars compared to first molars, irrespective of furcation site. Although first molars had an early and higher prevalence of Class III furcation involvement than second molars, the latter reached a significantly higher missing rate. Molars with longer root trunk lengths had a higher risk for poor prognosis than shorter root trunks when teeth were affected by Class III furcation involvement. For extracted furcation-involved maxillary second molars that failed to respond to periodontal therapy, long root trunk length (C) accounted for the greatest prevalence at the mesial furcation site (41.8%), followed by the distal (33.0%) and buccal sites (25.2%); the greatest prevalence of root trunk length C was found at the lingual (47.9%) and buccal furcation sites (45.1%) of mandibular second molars. When a molar with root trunk type C has a Class III involvement, the prognosis is poor; for the disease to reach that level, greater amounts of attachment must be destroyed.

Important prognostic factors of long-term oropharyngeal carcinoma survivors in Taiwan.

In Taiwan, a clear gender difference emerges for rates of oropharyngeal carcinoma incidence. The purpose of this study was to identify the gender differences and clinical factors associated with oropharyngeal carcinoma survival rates in Taiwan. We analyzed the 5-year survival rates of 8114 subjects diagnosed with oropharyngeal carcinoma between 1987 and 1994. The Cox proportional-hazards model identified clinical characteristics for gender according to oropharyngeal carcinoma death and all-cause death outcomes. The 5-year survival rates were significantly lower for males than females (p < 0.0001). The adjusted hazard ratio of males versus females was 1.54 (95% CI: 1.36-1.74) for oropharyngeal carcinoma death and 1.44 (95% CI: 1.31-1.58) for all-cause death. Gender and other clinical characteristics (i.e. diagnostic age, anatomic site, morphologic type, and treatment modality) play important roles in oropharyngeal carcinoma survival. We suggested that Taiwanese males have high proportion of betel quid chewing and that this is associated with the gender differences.

Betel nut chewing: the prevalence and the intergenerational effect of parental behavior on adolescent students.

PURPOSE: To explore the betel nut chewing prevalence among students, analyze the probability and the odds ratio of ex-chewers and current chewers, as well as the correlation between parental behavior characteristics and those of adolescents chewing betel nut. METHODS: A cross-sectional survey was designed and 10,288 Taiwanese students answered the questionnaires in 2002. A structured questionnaire included information about betel nut chewing behavior among the adolescent students, sociodemographic data, and the betel nut chewing practice among parents or classmates. Samples were randomly chosen from each cluster of different types of schools in various areas. Three different grade levels of the first, second, and third grade (ages 16-18 years) were selected. Frequency distribution was used to analyze the prevalence among adolescent students, and Chi-square tests were used to compare the differences of betel nut chewing behavior among genders and the effect of parental behavior and socioeconomic factors. Logistic regression was used to analyze the odds ratio of the prevalence of adolescent students' betel nut chewing in the different types of schools and by gender. RESULTS: When the parents' marriage was not successful, or was of a lower social status, a higher incidence of adolescent betel nut chewing was observed. It was easy to experience betel nut chewing in adolescence if either parent chewed betel nut. The prevalence of betel nut chewing among male students was higher than female students and among vocational school students than general school students. The odds ratio of agricultural school students to general school students was highest of all the ex-chewers and current chewers from different types of schools. CONCLUSIONS: Betel nut chewing behavior is related to the effect of parental behavior on adolescent students. Apparently, it is indicated that there is a significant intergenerational effect of the parent's behavior on their children's behavior.