Risk factors associated with periodontal disease and its impact on quality of life among pregnant women.

BACKGROUND: Periodontal disease during pregnancy affects maternal oral health and increases the risk of adverse pregnancy outcomes. However, studies on the risk factors for periodontal disease and its impact on oral health-related quality of life in pregnant women in Taiwan are lacking. This present study aimed to identify the risk factors associated with periodontal disease during pregnancy and examine the relationship of periodontal disease with oral health-related quality of life among pregnant women. METHODS: This study was conducted in a large medical centre in northern Taiwan. Eighty-four participants completed a periodontal examination by dentists as well as structured questionnaires, including the Oral Health Impact Profile-14, demographics, obstetric history, dietary habits, and oral hygiene behaviours. Multivariate logistic regression was used to determine the risk factors associated with periodontal disease and a t-test was used to compare the difference in oral health-related quality of life between pregnant women with and without periodontal disease. RESULTS: Fifty participants (59.5%) had periodontal diseases. Risk factors for periodontal disease included eating out for lunch, consuming beverages, brushing less than three times per day, and not receiving regular professional dental cleanings. The oral health-related quality of life was significantly poorer in pregnant women with periodontal disease than in those without. CONCLUSIONS: The risk factors for periodontal disease, including eating out for lunch, drinking beverages, brushing teeth less, and not regular dental cleaning, provide convincing evidence for pregnant women to maintain good oral hygiene to prevent periodontal disease and improve oral health-related quality of life.

Pregnancy can cause poor mouth health. Expectant mothers with gum disease might face problems such as low birth weight and premature birth. This study found that certain factors can worsen gum disease during pregnancy. These include eating out for lunch, drinking sugary or acidic drinks, brushing their teeth less than three daily, and skipping regular teeth cleaning by a dentist. Pregnant women with gum disease also reported a lower quality of life related to oral health compared to those without it. Healthcare providers should educate pregnant women about oral health maintenance. Emphasize the importance of professional dental cleanings every three months, frequent tooth brushing, avoiding sugary and acidic drinks, and reducing eating out for lunch. Future research should explore additional ways to support pregnant women in this regard.

A Socket Seal Technique With the Use of Autologous Dental Roots for Socket Seal: A Case Series.

The literature identified variations in socket seal surgery, each with limitations. This case series aimed to observe the outcome of using autologous dental root (ADR) for socket sealing on socket preservation (SP). A total of 9 patients with 15 extraction sockets were documented. After flapless extraction, the xenograft or alloplastic grafts were placed in the sockets. Autologous dental roots were prepared extraorally and applied to seal the socket entrance. All SP sites healed uneventfully. Cone-beam computed tomography (CBCT) scan was performed after 4-6 months of healing to evaluate ridge dimensions. The preserved alveolar ridge profiles were verified on CBCT scans and during implant surgery. Implants were placed successfully with a reduced need for guided bone regeneration. Histological biopsy specimens were examined in 3 cases. The histological examination demonstrated vital bone formation and osseointegration of graft particles. All patients completed the final restorations and were monitored for 15.56 ± 9.08 months after functional loading. The favorable clinical outcomes support the use of ADR for SP procedures. It was not only accepted to patients but also easy to perform with low complication rates. The ADR technique is thus a feasible method for socket seal surgery.

Convergent angles of a tapered implant referred from the root profile of premolars.

Background/purpose: Limited studies have discussed the convergent profiles regarding tapered implants based on biological considerations. This study analyzed the convergent angles (CAs) of premolar roots and imitated a tapered implant according to the anatomy of tooth roots. Materials and methods: A total of 60 single-rooted premolars were explored by micro-computed tomography. Every individual root was divided into 10 segments corono-apically, and the roots' buccolingual (BL) and mesiodistal (MD) CAs were measured by sections. To mimic a dental implant, the irregular shape of examined root cross-sections was transformed into a circular shape with equal areas. A biomimetic dental implant (BDI) was reconstructed and its CAs were compared with those of the natural roots' BL and MD at the examined levels and overall estimation. Results: In general, the maxillary and mandibular premolars demonstrated comparable CA patterns. However, significantly different CA patterns of BL, MD, and BDI were developed for both the maxillary and mandibular roots at the examined levels. The BL's CAs were greater than those CAs measured from the BDI and MD aspects, particularly for the sections at the middle and apical thirds of the roots. For overall CAs, the BDI's CAs were comparable with the average CAs of the BL and MD for both premolar groups. Conclusion: Instead of a cylindrical configuration, the BDI prototype demonstrated a tapered model with a continuous slope. The average CA of BDI was 14°-24°, serving as a biological reference for future tapered implant design and research.

The risk of endocarditis in hemodialysis patients who have undergone invasive dental treatment: a cohort case-control analysis of the Taiwan National Health Insurance Database.

OBJECTIVE: The objective of this study was to determine if hemodialysis patients who have undergone an invasive dental treatment are at risk of developing infective endocarditis. MATERIALS AND METHODS: This study was a cohort case-control design and used secondary data collected from the National Health Insurance Research Database of Taiwan. The case group and the control group were each comprised of 19,602 hemodialysis patients. The control group was matched for four variables: age, gender, a medical history of diabetes mellitus, and a cerebrovascular event. After matching, the case group and the control group were each comprised of 19,602 hemodialysis patients. Cox regression analysis determined hazard ratios and 95% confidence intervals. RESULTS: Patients were followed up at 1 month and 3 months after receiving invasive dental treatment. The results showed the cohort case-control hazard ratio was 0.88 (95% CI, 0.49, 1.57) 1 month after receiving invasive dental treatment. Three months after receiving IDT, the cohort case-control hazard ratio was 1.04 (95% CI, 0.71, 1.52). Hazard ratios did not differ significantly between groups. CONCLUSIONS: Hemodialysis patients who received invasive dental treatment had no greater risk of developing infective endocarditis than matched control patients. The results of this study should alleviate concerns for hemodialysis patients and dentists about invasive dental treatment procedures. We recommend hemodialysis patients undergo invasive dental treatment when needed. CLINICAL RELEVANCE: The results of this study showed that invasive dental treatment did not increase their risk of developing infective endocarditis. Hemodialysis patients in need of an invasive dental procedure should be encouraged to undergo treatment if the dentist deems it necessary.

The correlation between two occlusal analyzers for the measurement of bite force.

BACKGROUND: Occlusal force represents masticatory function. Using quantifiable occlusal indicators provides a more objective occlusal force evaluation. In the recent dental practice, digital methods such as the Dental Prescale II (DP2, GC Corp., Tokyo, Japan) and T-scan (T-Scan III v8; Tekscan Inc.) are commonly used in clinics to evaluate treatment outcomes. The T-scan provides the relative bite force (%) compared to the maximal bite force on individual teeth or the unilateral arch. The DP2 can quantify occlusal force, measured in newtons (N), on the half arch or the overall bite, but it is difficult to identify the bite force on an individual tooth. It is difficult to select a device that fulfils all the requirements to record occlusal force. This study aimed to investigate the association between the bite measured by the DPS2 and T-scan to determine whether the measured bite force is comparable through calculation. METHODS: A total of 80 healthy adults, including 41 women and 39 men with a mean age of 38.2, were requested to bite pressure sensitive film sheets ten minutes apart. Linear regression analysis was used to estimate the measured bite force by the DP2 and T-scan. RESULTS: There was a significant positive correlation between the occlusal force measured by the DP2 and T-scan (P < 0.01) when intercept was equal to zero as confounders were adjused. These results provided the comparability of the measured occlusal forces determined by the DP2 and T-scan. CONCLUSION: The estimated bite force determined by DP2 and T-Scan is convertible using the linear equation from this study to increase the value for clinical applications. The estimated bite force from the two quantifiable occlusal indicators are comparable. The two commercially available quantifiable occlusal indicators can be fully adapted to all clinical requirements according to this result.

The developing patterns of calibrated implant stability quotients of posterior implants.

BACKGROUND/PURPOSE: Many surgical protocols were modified to improve implant stability. However, the conclusions of applying osteotome condensation technique could enhance implant stability were controversial. The evaluated implant stability quotients (ISQ) were calibrated to differentiate the implant stability improvement that applied by varied surgical techniques and the bone quality at recipient sites. Therefore, this study examine the developing patterns of calibrated ISQ values induced by osteotome bone condensation and conventional drilling technique at the posterior ridges. MATERIALS AND METHODS: The ISQ values of 4.1/4.8-mm diameter implants were calibrated by 3.3-mm diameter implants (ISQb). Osteotome condensation technique was applied on the sites with ISQb ≤ 65 while those with ISQb > 65 were treated with conventional drilling technique. The implant ISQ values at Week 0, 1, 2, 3, 4, 6, 8, 10, 12 were recorded. The detected and calibrated ISQ values were statistically analyzed. RESULTS: Maxillary 14 implants and mandibular 16 implants using osteotome technique, maxillary 15 implants and mandibular 16 implants with conventional drilling technique were studied. Both techniques showed a generally similar ISQ developing pattern at both arches. Without calibration, significantly less ISQ values were noted for the osteotome technique of posterior maxilla at initial four weeks; subsequently, both techniques presented a comparable ISQ developing pattern. Osteotome technique demonstrated a greater ISQ increase after calibration on both arches (p < 0.05). All implants reached an ISQ stability plateau between Week 8 and 10. CONCLUSION: With calibration, osteotome condensation technique could enhance greater primary and secondary implant stability for both arches.

Calcitriol and enamel matrix derivative differentially regulated cemento-induction and mineralization in human periodontal ligament-derived cells.

BACKGROUND: Alveolar bone and cementum share many biological and developmental similarities. The mineralizing effect of calcitriol has been previously reported. Yet, its cemento-inductivity has not been confirmed. This study evaluated the potential cemento-inductivity effect of calcitriol and enamel matrix derivative (EMD) on human periodontal ligament-derived cells (hPDLCs). METHODS: The hPDLCs obtained from extracted third molars or premolars were cultured with calcitriol, or EMD. Cementogenic gene expression was examined using real-time quantitative reverse transcription polymerase chain reaction. Expression analysis also included cementoblast-specific markers, cementum protein 1 (CEMP1), cementum attachment protein (CAP), and recently reported cementoblast-enriched genes, secreted frizzled related protein 1 (SFRP1), and Dickkopf-related protein 1 (DKK1). Mineralization capacities were evaluated by alkaline phosphatase (ALP) activity, Alizarin Red, and Von Kossa staining followed by scanning electron microscope imaging and element mapping. RESULTS: Among tested conditions, 10 nM calcitriol enhanced most cementogenic gene expression, transforming growth factor-ß1, bone morphogenetic proteins (BMP-2 and BMP-4), core-binding factor subunit alpha-1/Runt-related transcription factor 2, Type I collagen, ALP, bone sialoprotein, osteopontin), osteocalcin, CEMP1, and CAP, and Wnt signaling negative modulators, SFRP1 and DKK1, along with highest ALP activity and mineralization formation in hPDLCs. However, only moderate CEMP1 protein was observed. In contrast, EMD stimulated stronger CEMP1 and CAP protein, but presented weaker mineralization capacity, hinting at the possibility that strong stimulation of mineralization might dominate cemetogenic specific factors and vice versa. CONCLUSIONS: Calcitriol demonstrated not only great osteoinductivity, but also the potential to induce cementogenic gene expression by initiating hPDLC differentiation and promoting mineralization. Compared with calcitriol, EMD promoted cemento-inductivity in hPDLCs at a later time point via highly expressed CEMP1 and CAP protein, but with less mineralization. Thus, calcitriol and EMD could provide differential enhancement of cemento-induction and mineralization, likely acting at various differentiation stages.

Characteristics of the convergent angles of tapered implants based on a premolar root model.

STATEMENT OF PROBLEM: Developing tapered implants with the most appropriate angular characteristics requires an improved analysis of the anatomy of premolar roots. PURPOSE: The purpose of this observational study was to analyze the 3D anatomy of premolar roots by determining the tapered slope and convergent angle (TS/CA), to transform the TS/CA patterns into those in which the tapered implants mimic natural tooth roots, and to provide TS/CA references for future investigations. MATERIAL AND METHODS: A total of 73 human single-rooted premolars were surveyed and analyzed by microcomputed tomography and an associated software program. The 3D root surface area (RSA), the radius/diameter (R/D) at the planned first to tenth millimeter levels apical to the cementoenamel junction (CEJ), and the TS/CA at corresponding levels were calculated. The results were statistically analyzed by using an independent samples t test to assess the general differences of tested parameters between maxillary and mandibular premolars. A paired t test was used to examine the significant intragroup TS/CA differences between sequential coronoapical levels. One-way ANOVA was applied to study the general significance of developmental patterns in maxillary and/or mandibular groups. Two-way ANOVA was used to inspect the TS/CA significance at various measurements coronoapically between the maxillary and mandibular premolars (α=.05). RESULTS: Generally, the RSA, root length, R/D, and TS/CA parameters examined for the maxillary premolar roots differed significantly from those for the mandibular roots at the evaluated levels (P<.05). According to the measurements, the maxillary premolar roots generally exhibited nonsignificant RSA and R/D reduction patterns, with a decreasing angle of TS=13.44 degrees and CA=24.53 degrees coronoapically. However, mandibular premolar roots exhibited a significant reduction pattern, with TS=11.25 degrees and CA=21.06 degrees coronoapically according to both individual and general evaluations. CONCLUSIONS: Based on the developmental patterns of the evaluated TSs/CAs, tapered implants imitating premolar root anatomy should have a conical rather than a cylindrical shape, and the R/D of these models should be reduced to half at the apical third. However, further studies are warranted to identify more TS/CA characteristics related to the tapered implants, including the TSs/CAs of other tooth types.

Application of dental stem cells in three-dimensional tissue regeneration.

Dental stem cells can differentiate into different types of cells. Dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, stem cells from apical papilla, and dental follicle progenitor cells are five different types of dental stem cells that have been identified during different stages of tooth development. The availability of dental stem cells from discarded or removed teeth makes them promising candidates for tissue engineering. In recent years, three-dimensional (3D) tissue scaffolds have been used to reconstruct and restore different anatomical defects. With rapid advances in 3D tissue engineering, dental stem cells have been used in the regeneration of 3D engineered tissue. This review presents an overview of different types of dental stem cells used in 3D tissue regeneration, which are currently the most common type of stem cells used to treat human tissue conditions.

Vertical dimension of occlusion related to mandibular movement during swallowing.

BACKGROUND: Increasing the vertical dimension of occlusion (VDO) is a common procedure in complicated prosthodontic treatment. The swallowing technique had been verified as a functional method to determine the VDO. The purpose of this study was to investigate the association between increasing VDO and mandibular movement during swallowing. METHODS: 26 females and 14 males were enrolled (age range: 21 to 30 year-old). Under different increased VDO (3, 5, and 8 mm), the mandibular trajectory during swallowing was measured by K7 Evaluation System (Myotronics®). When the subjects were instructed to salivary swallowing, the range of mandibular movement in vertical, anteroposterior and lateral directions were recorded. RESULTS: Increasing VDO significantly impacted the range of mandibular movement in lateral direction during swallowing (p < 0.0001, F value = 40.09). The average variance of the mandibular movement distance in lateral direction during swallowing raise 1.58 (p = 0.001); 3.59 (p = 0.0001) and 2.01 (p = 0.001) when th VDO was raised from 3 mm to 5 mm; from 3 mm to 8 mm and from 5 to 8 mm respectively. The range of mandibular movement was significantly correlated to the increasing VDO (p ≤ 0.05) under the analysis of the Post Hoc test. CONCLUSIONS: VDO was closely correlated to the trajectory of mandibular motion during swallowing. The increase in VDO could change the extent of mandibular trajectory during swallowing if the increase was more than 3 mm. The range of mandibular motion when swallowing had positive correlative tendency as the VDO was increased.

The impact of timing and modalities of dental prophylaxis on the risk of 5-fluorouracil-related oral mucositis in patients with head and neck cancer: a nationwide population-based cohort study.

PURPOSE: This study investigated the impact of dental prophylaxis on 5-fluorouracil (5-FU)-related oral mucositis (OM) according to the head and neck cancer (HNC) locations and treatment times. METHODS: A total of 13,969 HNC participants, including 482 5-FU-related OM subjects and 13,487 comparisons were enrolled from the Longitudinal Health Insurance Database for Catastrophic Illness Patients of Taiwan between 2000 and 2008. All subjects were stratified into subgroups based on the times to perform chlorhexidine use, scaling, and fluoride application before 5-FU administration. The dental prophylaxis related to 5-FU-related OM was estimated by multiple logistic regression and represented with odds ratio (OR) and 95% confidence interval (CI). RESULTS: Fluoride gel application and scaling significantly impacted on OM development (p < 0.001), and the joint effect of fluoride gel and scaling induced 5-FU-related OM (OR = 3.46, 95% CI = 2.39-5.01). The risk of OM was raised 2.25-fold as scaling within 3 weeks before 5-FU-related chemotherapy (95% CI = 1.81-2.81), and a 3.22-fold increased risk of OM while fluoride gel was applied during 5-FU-related treatment (95% CI = 1.46-7.13). CONCLUSION: Dental prophylaxis significantly affected 5-FU-related OM in the HNC population. A short interval between dental scaling or fluoride application and 5-FU administration may be associated with higher prevalence of OM. Scaling simultaneously combined with chlorohexidine promoted 5-FU-related OM in specific HNC patients excluding the oral cancer and nasopharyngeal cancer population. Proper timing of the prophylactic dental treatments prior to 5-FU therapy could reduce the risk to develop 5-FU-related OM.

The correspondence of 3D supporting bone loss and crown-to-root ratio to periodontitis classification.

AIM: Assessing the application of three-dimensional clinical attachment loss (3D-CAL), 3D supporting bone loss (3D-SBL), supracrestal tissue attachment (STA), and crown-to-root ratio (CRR) in evaluating the 2017 periodontitis classification. MATERIALS AND METHODS: We analysed ninety single-rooted human premolars with micro-computed tomography. The amount of 3D-SBL, linear radiographic bone loss (RBL), and CRR corresponding to various periodontitis stages as well as the statistical significance was investigated. RESULTS: From a 3D perspective, the premolars with a 21% of 3D-SBL at 2.0 mm coronal root length (RL) and 15% RBL corresponded to the periodontitis stage I. Premolars with a 44% of 3D-SBL at coronal 4.2-4.4 mm RL and 33% RBL accorded with the periodontitis stage II. Excluding the consideration of STA, CRR = 5:6 and 4:3 were associated with the levels at 15% and 33% RBL, respectively. CONCLUSIONS: A greater percentage of 3D-CAL than that of 2D-CAL is significant at evaluated levels. It is feasible to correlate the 3D-SBL, 3D-CAL, and STA parameters to evaluate the stages of periodontitis severity. However, the current use of RBL and CAL as applied for staging in the 2017 classification might be inconsistent with the evaluated premolar roots length, when STA dimensions are considered.

Incidence Rate and Predictors of Globus Pallidus Necrosis after Charcoal Burning Suicide.

Objective: This study examined predictors of globus pallidus necrosis as there was a paucity of literature of globus pallidus necrosis resulted from carbon monoxide poisoning after charcoal burning suicide. Methods: A total of 67 patients who had attempted charcoal burning suicide were recruited and stratified into two subgroups based on either presence (n = 40) or absence (n = 27) of globus pallidus necrosis. Demographic, clinical, laboratory, and radiographic data were obtained for cross-sectional analysis. All patients were followed to investigate the risks for mortality. Results: The patients aged 36.8 ± 11.1 years (67.2%) were male. Patients with globus pallidus necrosis were younger (p = 0.044) and had less hypertension (p = 0.015) than patients without globus pallidus necrosis. Furthermore, patients with globus pallidus necrosis suffered from severer medical complications, i.e., fever (p = 0.008), acute myocardial injury (p = 0.022), acute rhabdomyolysis (p = 0.022), and neuropsychiatric symptoms (p < 0.001) than patients without globus pallidus necrosis. Moreover, patients with globus pallidus necrosis received less hyperbaric oxygen therapy than without necrosis (p = 0.024). Two patients (3.0%) died on arrival. In a multivariable regression model, it was revealed that acute myocardial injury (odds ratio 4.6, confidence interval 1.1-18.9, p = 0.034) and neuropsychiatric symptoms (odds ratio 8.0, confidence interval 2.0-31.4, p = 0.003), decreased blood bicarbonate level (odds ratio 0.8, confidence interval 0.7-1.0, p = 0.032), and younger age (odds ratio 0.9, confidence interval 0.9-1.0, p = 0.038) were significant predictors for globus pallidus necrosis. Conclusion: Although patients who had attempted charcoal burning suicide had a low mortality rate (3.0%), globus pallidus necrosis was not uncommon (59.7%) in this population. Further studies are warranted.

Acute kidney injury and the risk of mortality in patients with methanol intoxication.

BACKGROUND: Methanol poisoning is a serious public health issue in developing countries, but few data are available in the literature on acute kidney injury (AKI) after methanol intoxication. METHODS: This study examined the clinical features, spectrum and outcomes of AKI in patients with methanol intoxication and evaluated the predictors of mortality after methanol intoxication. A total of 50 patients with methanol intoxication were seen at Chang Gung Memorial Hospital between 2000 and 2013. Patients were grouped according to the status of renal damage as AKI (n = 33) or non-AKI (n = 19). Demographic, clinical, laboratory, and mortality data were obtained for analysis. RESULTS: Most patients were middle-aged (47.8 ± 14.9 years), predominantly male (74.0%), and habitual alcohol consumers (70.0%). Most incidents were oral exposures (96.0%) and unintentional (66.0%). Two (4.0%) patients attempted suicide by intravenous injection of methanol. Five (10.0%) patients suffered methanol intoxication after ingestion of methomyl pesticide that contained methanol as a solvent. Compared to non-AKI patients, the AKI patients were older (50.9 ± 13.7 versus 41.6 ± 15.6 years, P = 0.034), predominantly male (90.9% versus 42.8%, P = 0.000), more habitual alcohol users (84.8% versus 41.2%, P = 0.001) and had more unintentional exposures (82.8% versus 35.3%, P = 0.001). Furthermore, there was a higher incidence of respiratory failure (63.6% versus 29.4%, P = 0.022) in the AKI group than in the non-AKI group, respectively. The laboratory studies revealed that the AKI patients suffered from more severe metabolic acidosis than the non-AKI patients. By the end of this study, 13 (39.5%) AKI patients and 1 (5.9%) non-AKI patient had died. The overall in-hospital hospital mortality rate was 28%. In a multivariate binary logistic regression model, it was demonstrated that AKI (odds ratio 19.670, confidence interval 1.026-377.008, P = 0.048) and Glasgow coma scale score (odds ratio 1.370, confidence interval 1.079-1.739, P = 0.010) were significant factors associated with mortality. The Kaplan-Meier analysis disclosed that AKI patients suffered lower cumulative survival than non-AKI patients (log-rank test, chi-square = 5.115, P = 0.024). CONCLUSIONS: AKI was common (66.0%) after methanol intoxication and was predictive of in-hospital hospital mortality. The development of AKI was associated with a 19.670-fold higher risk of in-hospital mortality.

Calcitriol exerts a mineralization-inductive effect comparable to that of vitamin C in cultured human periodontium cells.

This study inspected whether calcitriol could exert a mineralization-inductive effect comparable to that of vitamin C in cultured human periodontium cells (hPDCs). The mRNA expression of the mineralization-related biomarkers core-binding factor subunit alpha-1 (Cbfa1), collagen 1 α1 (Col-I), alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), vitamin D receptor (VDR), cementum protein 1 (CEMP-1), cementum attachment protein (CAP), interleukin 6 (IL-6), transforming growth factor-ß1 (TGF-ß1) and osteoprotegerin (OPG) was surveyed after incubation of hPDCs with vitamin C and calcitriol for 2 weeks. Translational expression information from ALP activity and CEMP-1 and CAP immunofluorescence assays was acquired from hPDCs at the second and third weeks. Extracellular calcifications were confirmed by von Kossa staining, Alizarin Red staining and synchrotron transmission X-ray microscopy (TXM) at the fourth and fifth weeks. It was found that both vitamin C and calcitriol not only increased mineralization-related mRNA fold-changes but also enhanced ALP activity, CEMP-1 immunofluorescence, von Kossa and Alizarin Red staining and TXM-associated calcifications. Generally, 10-8 M calcitriol displayed greater mineralization significance than 10-7 M calcitriol in the assays tested. However, vitamin C stimulated lower Cbfa1, Col-1, ALP, OPN, BSP, OCN, VDR, CEMP-1 and IL-6 mRNA fold-changes than 10-8 M calcitriol. Finally, TXM analysis indicated that a 10-8 M calcitriol treatment stimulated greater calcifications than vitamin C treatment. Therefore, the analytical results confirmed the osteo-inductive potential of vitamin C in cultured hPDCs. In contrast, 10-8 M calcitriol could potentially function as a substitute because it stimulates a greater mineralization effect than vitamin C or 10-7 M calcitriol.

Correction: Incompatible amount of 3-D and 2-D periodontal attachments on micro-CT scanned premolars.

[This corrects the article DOI: 10.1371/journal.pone.0193894.].

The association of variables of fibular reconstructed mandible and bite force in oral cancer patients with dental implant rehabilitation.

PURPOSE: The aim of this study was to investigate how the physical variables of fibular reconstructed mandibles with dental implants affects the relative bite force in oral cancer patients. MATERIALS AND METHODS: Over 7 years of follow-up, 13 oral cancer patients were enrolled who included 51 successful implants in the fibular flap. The tactile sensor analyzer evaluated the bite force. The crown-implant ratio, fibular, and rehabilitated dental length were measured using radiographic images. Linear regression was used to analyze the bite force related to the variables of the implants in the fibular reconstructed mandible. RESULTS: Even when the results showed no statistical significance (P > 0.05), increasing the crown-implant ratio, length of the fibular flap, and implant prosthetic reconstructed dentition had a tendency to decrease the bite force (estimate from -0.08% to -4.27%); there was a positive trend of occlusal force and the length of rehabilitative dentition compared with the dental antagonist (estimate = 6.95). CONCLUSION: In this study, the crown-implant ratio, implant dentition, and fibular flap length revealed no significant impact on the bite force or implant success in oral cancer patients; however, a trend to weaken the bite force was suggested once the numerical values of these variables increased.

Isolation of Mesenchymal Stem Cells from Human Alveolar Periosteum and Effects of Vitamin D on Osteogenic Activity of Periosteum-derived Cells.

Mesenchymal stem cells (MSCs) are present in a variety of tissues and can be differentiated into numerous cell types, including osteoblasts. Among the dental sources of MSCs, the periosteum is an easily accessible tissue, which has been identified to contain MSCs in the cambium layer. However, this source has not yet been widely studied. Vitamin D3 and 1,25-(OH)2D3 have been demonstrated to stimulate in vitro differentiation of MSCs into osteoblasts. In addition, vitamin C facilitates collagen formation and bone cell growth. However, no study has yet investigated the effects of Vitamin D3 and Vitamin C on MSCs. Here, we present a method of isolating MSCs from human alveolar periosteum and examine the hypothesis that 1,25-(OH)2D3 may exert an osteoinductive effect on these cells. We also investigate the presence of MSCs in the human alveolar periosteum and assess stem cell adhesion and proliferation. To assess the ability of vitamin C (as a control) and various concentrations of 1,25-(OH)2D3 (10-10, 10-9, 10-8, and 10-7 M) to alter key mRNA biomarkers in isolated MSCs mRNA expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), core binding factor alpha-1 (CBFA1), collagen-1, and osteocalcin (OCN) are measured using real-time polymerase chain reaction (RT-PCR).

Effect of mouth-opening levels on sound field gain in the ear canal.

The human external auditory canal can become deformed when the mandible moves, and this changes the sound field in the external auditory canal. This study measured the sound field gain in the external auditory canal while varying mouth-opening in three levels. The mandible was fixed at the 1/3, the 2/3, and the maximal mouth-opening levels. Seven 65-dB tones of 200, 500, 1000, 2000, 4000, 6000, and 8000 Hz, which are the sound pressure level and frequency range when people are talking at a normal level, were adopted as the sound stimulus to measure sound field gains at 5, 10, 15, and 20 mm to the interior of the external auditory canal. The results show that, with the exception of the 1.25 dB decrease from 12.96 to 11.71 dB at a depth of 5 mm with a stimulus at 8000 Hz, the differences in the sound field gain at the other depths and stimulus frequencies were within 1 dB and were not statistically significant. These results suggest that mouth-opening level has no effect on the measurement of the sound field in the external auditory canal.

Incompatible amount of 3-D and 2-D periodontal attachments on micro-CT scanned premolars.

Micro-computed tomography (micro-CT) was employed to relate the root surface area (RSA) to the periodontal attachment levels (PALs) of extracted premolars to diagnose periodontitis. Single-rooted human maxillary and mandibular premolars 31 and 36, respectively, were surveyed by micro-CT and its associated software. RSA levels from the 1st to 10th mm, corono-apically, were analyzed using statistical t tests. The average root length (RL) and RSA of the maxillary and mandibular premolars were significantly different (p < 0.05). Both premolars demonstrated a non-significant RSA percentage comparison at the evaluated PALs. For the 30% coronal 2-D radiographic RL, the 3-D RSAs 3.77 mm and 3.99 mm apical to the cementoenamel junction (CEJ) were 39.48% and 40.65% for maxillary and mandibular premolars, respectively. At the 15% coronal 2-D RL, the 3-D RSA 2 mm apical to the CEJ of the premolars was approximately 21%. At the 50% coronal 2-D RL level, approximately 62% coronal 3-D RSA and 6.5 mm RL decreased. The amount of decrease of the RSA attachment is significant in every 2-mm measurement for both premolars. Sampling periodontal microbial pathogens based on the condition of 2-D radiographic bone and clinical attachment losses without considering 3-D RSA is potentially inadequate and may underestimate the severity of the periodontitis.