Comparative prevalence of oral bacteria and protozoa in patients with periodontitis in Taiwan.

OBJECTIVES: Periodontitis is an inflammatory disease caused by bacteria present in the dental biofilm. However, the presence of two oral protozoans, Entamoeba gingivalis and Trichomonas tenax, in patients with the periodontal disease remains largely unknown in Taiwan. Therefore, we investigated the prevalence of oral microbial infections between the sites with mild gingivitis and chronic periodontitis in patients. MATERIALS AND METHODS: We collected 60 dental biofilm samples from sites with mild gingivitis (probing depth <5 mm) and chronic periodontitis (probing depth ≥5 mm) from 30 patients at the National Cheng Kung University Hospital. The samples were analyzed via polymerase chain reaction and gel electrophoresis. RESULTS: Among oral protozoans, E. gingivalis and T. tenax were detected in 44 (74.07%) and 14 (23.33%) of all samples, respectively. Among oral bacteria, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were detected in 50 (83.33%), 47 (78.33%), and 48 (80.0%) samples, respectively. CONCLUSIONS: This study, which is the first to analyze E. gingivalis and T. tenax presence among patients with periodontitis in Taiwan, revealed an association between periodontitis and oral microbes.

The first study to detect co-infection of Entamoeba gingivalis and periodontitis-associated bacteria in dental patients in Taiwan.

Periodontitis, an inflammatory disease of the oral cavity, was caused by microbes from bacteria to protozoa. In this study, we detected protozoa, Entamoeba gingivalis and other three common pathogenic bacteria, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia by the Polymerase chain reaction (PCR) on patients.

The correlation among gripping volume, insertion torque, and pullout strength of micro-implant.

BACKGROUND/PURPOSE: The fixation stability is the key factor for orthodontic micro-implant to succeed. This study evaluated the mechanical properties of three types of micro-implants by analyzing their structural configurations. MATERIALS AND METHODS: Thirty micro-implants of three types (diameter 1.5 mm, Types A, B, C) were assessed. All micro-implants were manually driven into artificial bones at an 8-mm depth. The insertion torque (IT), pullout strength (PS), and gripping volume (GV) of each type were measured. The indexes of mechanical properties denoted as the PS/IT, GV/IT and PS/GV ratios. Intergroup comparisons and intragroup correlation were examined using statistical analysis. RESULTS: Type B had the greatest inner-outer diameter ratio (0.67), and Type A had the smallest (0.53). The IT of Type A (5.26 Ncm) was significantly (p = 0.038) lower than that of Type C (8.8 Ncm). There was no significant difference in the pullout strength. The GV of Type A (9.7 mm3) was significantly greater than Type C (8.4 mm3). Type C was significantly greater than Type B (7.2 mm3). The ratios of mechanical properties (PS/IT, PS/GV, and GV/IT) were found significant in intergroup comparison. The PS/GV ratio was in order: Type B (26.5) > Type A (23.0) > Type C (20.2). Spearman's rho rank correlation test showed that PS of Type B was correlated significantly with GV. CONCLUSION: The design of thread and gripping volume were the important factors that contributes to the mechanical strengths of micro-implant.

Clinical significance of buccal branches of the facial nerve and their relationship with the emergence of Stensen's duct: An anatomical study on adult Taiwanese cadavers.

OBJECTIVE: This observational study on adult Taiwanese cadavers focused mainly on the intersection of buccal branches of the facial nerve with Stensen's duct, using the emergence of Stensen's duct as the reference landmark. MATERIALS AND METHODS: Thirty-five cadaveric hemifaces were included in our research. Samples with facial defects due to tumor, trauma, or surgery were all excluded. Buccal branches of the facial nerve were identified according to the Gray's Anatomy 40th edition definition. The distance was measured from the intersection to the emergence of Stensen's duct, running from the anterior border of the parotid gland. RESULTS: In the 35 hemifaces, the number of buccal branch/Stensen's duct intersections ranged from 1 to 5 (average 2.49 ± 1.15). Two-point intersections accounted for 37% (13 hemifaces) of the sample, forming the largest group. Samples of facial nerve buccal branches were divided into four types: Type 1, with two buccal branches, accounted for 37.15% (13/35); Type 2, with three buccal branches, made up 48.59% (17/35) of our samples - the biggest group (Type 2-a was the most frequent pattern among our samples, with two superior buccal branches and one inferior buccal branch, accounting for 34.31% of our samples); Type 3, with four buccal branches, accounted for only 5.7%. Three cases of double Stensen's duct were classified as Type 4, though this is supposed to be a very rare anatomical variation. With Type 2a, the most frequent pattern among our specimens, the distance from the emergence of the Stensen's duct to the emergence point of the first superior buccal branch along the anterior border of the parotid gland was 9.58 ± 5.68 mm. The distance from the emergence point to the emergence of the inferior buccal branch along the anterior border of the parotid gland was 11.03 ± 5.38 mm. The distance (D1) from Stensen's duct to the emergence of the first superiorly located buccal branch of the group Type 2-a was statistically different from the distance (D1) of the other groups (p = 0.02). No direct anastomoses or communicating fibers between upper and lower buccal branches were noted in 11 hemifaces (31%). CONCLUSION: The distribution of buccal branches was described using the emergence of Stensen's duct as a reference landmark. According to our observations, the relationship between the buccal branches and Stensen's duct was much more complicated than described in previous studies. This was the first study to investigate the complete distribution of buccal branches of the facial nerve emerging from the anterior of the parotid gland, and their relative locations and branching numbers.

Effectiveness of an oral function intervention for older Taiwanese people.

OBJECTIVE: Oral function disorders occur often in older people with increasing age. Oral function disorders affect bodily function and self-esteem, which are related to quality of life (QOL). The aim of this study was to evaluate the effectiveness of an oral function intervention programme on the oral function of older Taiwanese people. MATERIALS AND METHODS: A one-group pretest-post-test study design was used. A total of 529 older Taiwanese people (women, 68.2%; men, 31.8%; average age, 75.07 ± 5.95 years) participated in this study. The oral function intervention programme consisted of a brief oral health education programme and oral function exercises. The total test period was 8 months. The oral condition and function examination comprised two questionnaires (self-reported symptoms of oral function disturbance and the Geriatric/General Oral Health Assessment Index [GOHAI]) and three oral function assessments (Repetitive Saliva Swallowing Test [RSST], Oral Diadochokinesia Test [ODT] and Cheek Expanding Test [CET]). RESULTS: After the oral function intervention, the self-reported symptoms on the oral function questionnaire and GOHAI showed significant improvement (P < 0.05). Additionally, RSST, ODT and CET showed differences between pretest and post-test measurements (P < 0.05). CONCLUSION: The oral function intervention programme was effective in maintaining their feeding, swallowing and articulatory functions of older Taiwanese people. Significant improvements in self-reported symptoms of oral function and GOHAI scores indicated that the oral function intervention programme might improve the QOL of older Taiwanese people.

Gripping and Anchoring Effects on the Mechanical Strengths of Orthodontic Microimplants.

PURPOSE: The aim of this study was to evaluate the mechanical strengths in 5 different designs of orthodontic microimplants by analyzing their configuration of structure. MATERIALS AND METHODS: Thirty microimplants of 5 types (diameter 1.5 mm: type A, B, and C; diameter 1.3 mm: type D and E) were assessed. All microimplants were manually driven into the artificial bones at a 7-mm depth. The anchor area (AA), gripping area (GA), insertion torque (IT), Periotest value (PTV), and pullout strength (PS) were measured. Intergroup and intragroup comparisons were used to detect their significant differences. RESULTS: In the intergroup comparison, type D had a least IT (4.5 Ncm). In the PTV analysis, type B had the largest AA (7.76 mm) and its PTV (1.6) was significantly least than the others. In the PS test, type C had the largest GA (2.40 mm) and its PS was the largest. Intragroup comparisons (IT and PS), type A, and type E presented positively significant correlation. GA revealed positive with PS, and AA showed reverse tendency with PTV. CONCLUSION: The more AA of microimplants, the more stable they are. The more GA of microimplants, the more PS they are. Therefore, type C was better than the others because it had the largest GA and second largest AA.

The Effect of Pterygomasseteric Sling's Area in the Postoperative Stability after Mandibular Setback Surgery.

PURPOSE: The purpose of the present study was to investigate the correlation between the postoperative stability and area of pterygomasseteric sling (PMS). MATERIALS AND METHODS: Forty patients of mandibular prognathism were treated by isolated mandibular setback. Serial lateral cephalograms were collected (preoperatively [T1], immediately after surgery [T2], and more than 1 year postoperatively [T3]). The postoperative stability (T32) was divided into 3 groups (total, forward, and backward movements). The areas of PMS, immediate surgical changes (T21), postoperative stability (T32), and final surgical change (T31) were analyzed by Student's t-test, Pearson's correlation coefficient, and multiple linear regression analysis. RESULTS: The amount of mean setback (T21) was 12.6 mm in total group, 13.8 mm in forward group, and 10.8 mm in backward group. In the total group, postoperative stability (T32) was 0.6 mm forward and reduction area of PMS (T31) was 291 mm2 (17.2%). The reduction area of PMS (T31) was 298.2 mm2 (18%) and 263.1 (15.3%) mm2 in the forward group (3 mm) and backward group (2.4 mm), respectively. However, reduction area of PMS (T31) showed weak correlation with postoperative stability (T32) in all groups. CONCLUSION: Total and forward groups presented significant correlations between postoperative stability (T32) and amount of setback (T21).

Effects of gripping volume in the mechanical strengths of orthodontic mini-implant.

The objective of study was to investigate the correlation between the mechanical strengths [insertion torque (IT); resonance frequency (RF); and horizontal pullout strength (HPS)] and gripping volume (GV) of mini-implants. Thirty mini-implants of three types (Type A: 2 mm × 10 mm, cylindrical, titanium alloy; Type B: 2 mm × 10 mm, tapered, stainless steel; and Type C: 2 mm × 11 mm, cylindrical, titanium alloy) were inserted 7 mm into artificial bones. One-way analysis of variance and Spearman's test were applied to assess intergroup comparisons and intragroup correlations. The null hypothesis was that no statistically significant correlations exist between the GV and mechanical strengths (IT, RF, and HPS). In the IT test, Type C (14.2 Ncm) had significantly (p=0.016) greater values than did Type A (12.4 Ncm). In the RF analysis, no significant difference was observed among the three types of mini-implants. In the HPS test, Type C (388.9 Ncm) was significantly larger than both Type B (294.5 Ncm) and Type A (286 Ncm). In the GV measurement, Type C (14.4 mm3) was significantly larger than Type B (11.4 mm3) and Type A (9.2 mm3). Type A and Type B exhibited no significant correlations among the tests. Therefore, the null hypothesis was accepted. Although no significant correlation was noted between the GV and mechanical strengths (IT, RF, and HPS), we observed a trend that the mechanical strengths (IT, RF, and HPS) of the mini-implants corresponded to the order and values of GV (Type C > Type B > Type A).

Effect of Anchor Length on the Pullout Strength of Palatal Mini Implants.

PURPOSE: The aim of this study was to evaluate the pullout strength of 3 different orthodontic mini implants. MATERIALS AND METHODS: Twenty-seven mini implants (diameter: 2 mm, length: 7 mm) were implanted into artificial bone (Sawbones; Pacific Research Laboratories Inc.) at depths of 3, 4, and 5 mm. The insertion torque (IT), resonance frequency (RF), pullout strength (PS), and anchor length (AL) were measured. One-way analysis of variance with Tukey honest significant difference (HSD) postcomparison were used to detect intergroup differences. The null hypothesis was that IT, RF, and PS would significantly correlate in the same brand. RESULTS: In the implantation depths (ID) (5 and 4 mm), IT of Types C (16.67 and 14.33 N·cm) and Type B (14 and 13.33 N·cm) were significantly higher than Type A (10.33 and 9.33 N·cm). Type A had a largest AL and PS at the IDs (5 and 4 mm). In the IDs (3 mm), PS was no different. Type C had no correlation among the RF, IT, and PS. Therefore, null hypothesis was rejected. CONCLUSION: AL exerted crucial effects on the PS of the mini implants.

Evaluation of mechanical strengths of three types of mini-implants in artificial bones.

We investigates the effect of the anchor area on the mechanical strengths of infrazygomatic mini-implants. Thirty mini-implants were divided into three types based on the material and shape: Type A (titanium alloy, 2.0×12 mm), Type B (stainless steel, 2.0×12 mm), and Type C (titanium alloy, 2.0×11 mm).The mini-implants were inserted at 90° and 45° into the artificial bone to a depth of 7 mm, without predrilling. The mechanical strengths [insertion torque (IT), resonance frequency (RF), and removal torque (RT)] and the anchor area were measured. We hypothesized that no correlation exists among the mechanical forces of each brand. In the 90° tests, the IT, RF, and RT of Type C (8.5 N cm, 10.2 kHz, and 6.1 N cm, respectively) were significantly higher than those of Type A (5.0 N cm, 7.7 kHz, and 4.7 N cm, respectively). In the 45° test, the RFs of Type C (9.2 kHz) was significantly higher than those of Type A (7.0 kHz) and Type B (6.7 kHz). The anchor area of the mini-implants was in the order of Type C (706 mm2)>Type B (648 mm2)>Type A (621 mm2). Type C exhibited no significant correlation in intragroup comparisons, and the hypothesis was accepted. In the 90° and 45° tests, Type C exhibited the largest anchor area and the highest mechanical strengths (IT, RF, and RT) among the three types of mini-implants. The anchor area plays a crucial role in the mechanical strength of mini-implants.

Comparison of intraoperative blood loss between four different surgical procedures in the treatment of bimaxillary protrusion.

OBJECTIVE: This study was aimed at investigating the correlation between intraoperative blood loss and operation-related factors in the treatment of bimaxillary protrusion with four different procedures. STUDY DESIGN: Ninety-four patients were separated into the following four surgical groups: group 1: anterior subapical osteotomy of the maxilla (ASO Mx) + bilateral parasymphyseal osteotomy of the mandible (BPsO Md) + genioplasty (GeP); group 2: ASO Mx + BPsO Md; group 3: ASO Mx + ASO Md + GeP; and group 4: ASO Mx + ASO Md. Patient- and operation-related factors (age, intraoperative blood loss, operation time, and preoperative and postoperative blood parameters) were compared among the four groups. RESULTS: The mean operation time and intraoperative blood loss were 438.7 minutes and 369.9 mL in group 1; 432.5 minutes and 356.5 mL in group 2; 393.3 minutes and 387.3 mL in group 3; and 353.5 minutes and 289.5 mL in group 4. Intergroup differences in intraoperative blood loss were not significant. A significant correlation between intraoperative blood loss and operation time was found in group 4 but not in the other groups. CONCLUSIONS: No significant differences in blood loss were found among the four different surgical procedures in the treatment of bimaxillary protrusion.

Effect of different acidities of electrolyzed water on dentin surface roughness, decalcification and microhardness -a preliminary study.

This study investigated the exposed coronal superficial dentin of 28 human molars were immersed in strongly acidic electrolyzed water (AW group), neutral electrolyzed water (NW group), 5% sodium hypochlorite (negative control, NL group), or deionized water (positive control, DW group). Microhardness was determined at 5-min intervals for 60 min. Surface roughness, energy dispersive X-ray spectroscopy and scanning electron microscopy analyses were performed after 5 and 60 min. Reductions in microhardness were observed in the AW, NW and NL groups, with further decreases as immersion time increased. Surface roughness was also markedly greater, and the Ca/P ratio markedly decreased, in the AW group. Prolonged immersion of dentin in strongly acidic electrolyzed water markedly decreased the microhardness and Ca/P ratio and markedly increased surface roughness. Prolonged immersion can lead to greater softening effect in dentin depending on the acidity of the electrolyzed water used.

Insertion torque, resonance frequency, and removal torque analysis of microimplants.

This study aimed to compare the insertion torque (IT), resonance frequency (RF), and removal torque (RT) among three microimplant brands. Thirty microimplants of the three brands were used as follows: Type A (titanium alloy, 1.5-mm × 8-mm), Type B (stainless steel, 1.5-mm × 8-mm), and Type C (titanium alloy, 1.5-mm × 9-mm). A synthetic bone with a 2-mm cortical bone and bone marrow was used. Each microimplant was inserted into the synthetic bone, without predrilling, to a 7 mm depth. The IT, RF, and RT were measured in both vertical and horizontal directions. One-way analysis of variance and Spearman's rank correlation coefficient tests were used for intergroup and intragroup comparisons, respectively. In the vertical test, the ITs of Type C (7.8 Ncm) and Type B (7.5 Ncm) were significantly higher than that of Type A (4.4 Ncm). The RFs of Type C (11.5 kHz) and Type A (10.2 kHz) were significantly higher than that of Type B (7.5 kHz). Type C (7.4 Ncm) and Type B (7.3 Ncm) had significantly higher RTs than did Type A (4.1 Ncm). In the horizontal test, both the ITs and RTs were significantly higher for Type C, compared with Type A. No significant differences were found among the groups, and the study hypothesis was accepted. Type A had the lowest inner/outer diameter ratio and widest apical facing angle, engendering the lowest IT and highest RF values. However, no significant correlations in the IT, RF, and RT were observed among the three groups.

Morphological alterations of periodontal pocket epithelium following Nd:YAG laser irradiation.

OBJECTIVE: The purpose of this in vivo study was to examine morphologic alterations in the periodontal pocket epithelium with presence or absence of clinical inflammation following the use of the Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser irradiation. BACKGROUND DATA: Subgingival Nd:YAG laser irradiation has been proposed as an alternative technique for treatment of chronic periodontitis. Several published studies have reported the clinical outcomes of such treatment. METHODS: Twenty patients, diagnosed with moderate chronic periodontitis, were selected for the study. A total of 32 sites was identified and divided into a control (n=18) and laser-treated test groups (n=14). Probing depth (PD) and bleeding on probing (BOP) were recorded for all sites. Test sites were irradiated with an Nd:YAG laser using parameters of 2 W, 200 mJ pulse energy, and 10 pps delivered through a 320 µm diameter tip. Total laser treatment time ranged from 1 to 2 min. Following treatment, all specimens were harvested via biopsy and processed for scanning electron microscopy (SEM) and histologic examination. RESULTS: Control group specimens, depending upon initial PD, exhibited either a relatively smooth and intact epithelium with little desquamation (PD≤3 mm), or increasing degrees of epithelial desquamation and leukocytic infiltration at a PD of ≥4 mm. In the laser-treated test group, the specimens with PD≤3 mm that were BOP negative (-) exhibited a thin layer of epithelium that was disrupted. In the specimens with initial PD of ≥4 mm, complete removal of the epithelium whose extent and degree were increasing, was observed in the inflamed portion, while epithelium remained in the uninflamed portion. CONCLUSIONS: The SEM and histologic findings demonstrated the feasibility of ablating pocket epithelium with an Nd:YAG laser irradiation using parameters of 2 W of power (200 mJ, 10 pps). Furthermore, the presence or absence of clinical inflammation appeared to have an impact on the degree of laser-mediated epithelial ablation.

Relationship between betel quid chewing and radiographic alveolar bone loss among Taiwanese aboriginals: a retrospective study.

BACKGROUND: Betel quid chewing is associated with the periodontal status; however, results of epidemiological studies are inconsistent. To the best of our knowledge, no study has reported radiographic alveolar bone loss (RABL) associated with betel quid chewing. METHODS: This survey was conducted in an aboriginal community in Taiwan because almost all betel quid chewers were city-dwelling cigarette smokers. In total, 114 subjects, aged 30-60 years, were included. Full-mouth intraoral RABL was retrospectively measured and adjusted for age, gender, and plaque index (PI). Multiple regression analysis was used to assess the relationship between RABL and potential risk factors. RESULTS: Age-, gender-, and PI-adjusted mean RABL was significantly higher in chewers with or without cigarette smoking than in controls. Multiple regression analysis showed that the RABL for consumption of 100,000 pieces betel quid for the chewer group was 0.40 mm. Full-mouth plotted curves for adjusted mean RABL in the maxilla were similar between the chewer and control groups, suggesting that chemical effects were not the main factors affecting the association between betel quid chewing and the periodontal status. CONCLUSION: Betel quid chewing significantly increases RABL. The main contributory factors are age and oral hygiene; however, the major mechanism underlying this process may not be a chemical mechanism. Regular dental visits, maintenance of good oral hygiene, and reduction in the consumption of betel quid, additives, and cigarettes are highly recommended to improve the periodontal status.

Immigrant-native differences in caries-related knowledge, attitude, and oral health behaviors: a cross-sectional study in Taiwan.

BACKGROUND: With the growing number of transnational marriages in Taiwan, oral health disparities have become a public health issue. This study assessed immigrant-native differences in oral health behaviors of urban mothers and their children. METHODS: We used the baseline data of an oral health promotion program to examine the immigrant-native differences in caries-related knowledge, attitude, and oral health behaviors. A cross-sectional study was conducted to collect data from mothers in urban area, Taiwan. A total of 150 immigrant and 440 native mothers completed the self-report questionnaires. Logistic regression models analyzed the racial differences in oral health behaviors. RESULTS: Approximately 37% of immigrant mothers used dental floss, 25% used fluoride toothpaste, and only 13.5% of them regularly visited a dentist. Less that 40% of immigrant mothers brush their children's teeth before aged one year, 45% replaced child's toothbrush within 3 months, and only half of the mothers regularly took their child to the dentist. Immigrant mothers had lower level of caries-related knowledge and attitudes than native mothers (p < .001). Compared to native group, the immigrant mothers were less likely to use of dental floss ([Adjusted odds ratio (aOR) =0.35], fluoride toothpaste (aOR = 0.29), visit a dentist in the past 2 years (aOR = 0.26), and take their children to regular dental check-up (aOR = 0.38); whereas, they were more likely to not consume sweeten beverages (aOR = 3.13). CONCLUSIONS: The level of caries-related knowledge, attitudes and oral health behaviors were found lower in immigrant mothers than native ones. The findings suggested cross-cultural caries prevention programs aimed at reducing immigrant-native disparities in child oral health care must be developed for these immigrant minorities.

Nd:YAG laser irradiation of the tooth root surface inhibits demineralization and root surface softening caused by minocycline application.

OBJECTIVE: The aim of this study was to investigate the effect of laser irradiation on root surface demineralization caused by local drug delivery systems (DDS), and to evaluate the effect of sealing on drug retention. BACKGROUND DATA: The duration of supportive periodontal treatment (SPT) has increased with increasing life expectancy. Repeated root planing and DDS application during SPT should be reconsidered with regard to their effects on the root surface. METHODS: Extracted human teeth were collected, cut into 3 × 3 × 2 mm root dentin specimens, and divided randomly into eight groups with various combinations of Nd:YAG laser power (0, 0.5, 1, and 2 W), with and without DDS (minocycline HCl). Specimen microhardness and calcium (Ca) solubility were measured after treatment. The specimens (control and laser and DDS groups) were examined by scanning electron microscopy. Forty SPT patients were recruited, to assess the effect of periodontal pocket sealing on drug retention. RESULTS: Laser irradiation increased the microhardness of root specimens in an energy-dependent manner. Calcium solubilities decreased from the 0 W+DDS group to the 2.0 W+DDS group. The mean Ca solubilities in the 1.0 W+DDS and 2.0 W+DDS groups were significantly lower than in the 0 W+DDS group (p<0.01, p<0.001, respectively). Laser irradiation counteracted the softening effect of DDS. Morphologic change was observed in the 2 W+DDS group; however, no morphologic changes were observed in the control and the 1 W+DDS groups. The mean concentration of minocycline in the periodontal pocket 24 h after application was 252.79 ± 67.50 µg/mL. CONCLUSIONS: Laser irradiation of the root surface inhibited the softening and decalcification caused by minocycline HCl. Sealing the periodontal pockets effectively improved drug retention. These results suggest that the combination of laser irradiation and DDS could benefit patients receiving repeated SPT.

Cytochrome p450 metabolism of betel quid-derived compounds: implications for the development of prevention strategies for oral and pharyngeal cancers.

Betel quid (BQ) products, with or without tobacco, have been classified by the International Agency for Research on Cancer (IARC) as group I human carcinogens that are associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. There are estimated 600 million BQ users worldwide. In Taiwan alone there are 2 million habitual users (approximately 10% of the population). Oral and pharyngeal cancers result from interactions between genes and environmental factors (BQ exposure). Cytochrome p450 (CYP) families are implicated in the metabolic activation of BQ- and areca nut-specific nitrosamines. In this review, we summarize the current knowledge base regarding CYP genetic variants and related oral disorders. In clinical applications, we focus on cancers of the oral cavity and pharynx and OPMDs associated with CYP gene polymorphisms, including CYP1A1, CYP2A6, CYP2E1, and CYP26B1. Our discussion of CYP polymorphisms provides insight into the importance of screening tests in OPMDs patients for the prevention of oral and pharyngeal cancers. Future studies will establish a strong foundation for the development of chemoprevention strategies, polymorphism-based clinical diagnostic tools (e.g., specific single-nucleotide polymorphism (SNP) "barcodes"), and effective treatments for BQ-related oral disorders.

Low-power laser irradiation promotes the proliferation and osteogenic differentiation of human periodontal ligament cells via cyclic adenosine monophosphate.

Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the proliferation and osteogenic differentiation of human PDL (hPDL) cells. Cultured hPDL cells were irradiated (660 nm) daily with doses of 0, 1, 2 or 4 J⋅cm(-2). Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase (ALP) activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Our data showed that LPLI at a dose of 2 J⋅cm(-2) significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J⋅cm(-2) showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate (cAMP) is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.