MyD88 exacerbates inflammation-induced bone loss by modulating dynamic equilibrium between Th17/Treg cells and subgingival microbiota dysbiosis.

BACKGROUND: This study aimed to investigate the contribution of myeloid differentiation primary-response gene 88 (MyD88) on the differentiation of T helper type 17 (Th17) and regulatory T (Treg) cells and the emerging subgingival microbiota dysbiosis in Porphyromonas gingivalis-induced experimental periodontitis. METHODS: Alveolar bone loss, infiltrated inflammatory cells, immunostained cells for tartrate-resistant acid phosphatase (TRAP), the receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) were quantified by microcomputerized tomography and histological staining between age- and sex-matched homozygous littermates (wild-type [WT, Myd88+/+] and Myd88-/- on C57BL/6 background). The frequencies of Th17 and Treg cells in cervical lymph nodes (CLNs) and spleen were determined by flow cytometry. Cytokine expression in gingival tissues, CLNs, and spleens were studied by quantitative polymerase chain reaction (qPCR). Analysis of the composition of the subgingival microbiome and functional annotation of prokaryotic taxa (FAPROTAX) analysis were performed. RESULTS: P. gingivalis-infected Myd88-/- mice showed alleviated bone loss, TRAP+ osteoclasts, and RANKL/OPG ratio compared to WT mice. A significantly higher percentage of Foxp3+CD4+ T cells in infected Myd88-/- CLNs and a higher frequency of RORγt+CD4+ T cells in infected WT mice was noted. Increased IL-10 and IL-17a expressions in gingival tissue at D14-D28 then declined in WT mice, whereas an opposite pattern was observed in Myd88-/- mice. The Myd88-/- mice exhibited characteristic increases in gram-positive species and species having probiotic properties, while gram-negative, anaerobic species were noted in WT mice. FAPROTAX analysis revealed increased aerobic chemoheterotrophy in Myd88-/- mice, whereas anaerobic chemoheterotrophy was noted in WT mice after P. gingivalis infection. CONCLUSIONS: MyD88 plays an important role in inflammation-induced bone loss by modulating the dynamic equilibrium between Th17/Treg cells and dysbiosis in P. gingivalis-induced experimental periodontitis.

Mapping out the bibliometric characteristics of classic articles published in a Taiwanese academic journal in dentistry: A scopus-based analysis.

Background/purpose: Since its inception, the Journal of Dental Sciences (JDS) has aimed to publish quality articles relevant to all fields in dentistry. The purpose of this study was to analyze the bibliometric characteristics and dissected associated factors correlated with citation counts of classic articles published in the JDS. Materials and method: Scopus® database was used to search the qualified articles published in JDS from 2009 to 2021. The bibliometric parameters, including journal impact factor (JIF), self-citation, study design, research field, geographic, country and institute of origin, inter-institute, inter-nation collaboration, keywords hotness and associated factors correlated with citation counts of classic articles were analyzed. Results: One hundred and eight articles from Scopus® database were eligible for analysis. The citation counts of classic articles ranged from 12 to 192, the average citation was 22.02. The most common study design was the in vitro/in vivo, followed by the cross-sectional study, and the major research field were Dental Materials. The most productive country and institute is Taiwan, and Chung Shan Medical University, respectively. The trend of inter-institute (71.03%) and inter-nation (11.22%) collaboration steadily increased since 2009. By using the multivariable linear regression model, Preventive and Community Dentistry in the research field significantly increased the citation counts. Conclusion: Despite its limitations, the escalating trends in JIFs, and JIFs without self-citations, and inter-nation and inter-institute collaboration of classic articles were noticed. Of all the dissected associated factors, Preventive and Community Dentistry in the research field significantly increased the citation counts of classic article.

Carpal tunnel syndrome in dentists compared to other populations: A nationwide population-based study in Taiwan.

BACKGROUND: Dentists may be at a higher risk of developing carpal tunnel syndrome (CTS) because of their use of frequent wrist and vibratory instruments at work; however, this issue remains unclear. Therefore, we conducted this study to clarify it. METHODS: Taiwan National Health Insurance Research Database was used for this nationwide population-based study. We identified 11,084 dentists, 74,901 non-dentist healthcare professionals (HCPs), and identical number of age- and sex-matched participants from the general population. Participants who had the diagnosis of CTS before 2007 were excluded. Between 2007 and 2011, the risk of developing CTS among dentists, non-dentist HCPs, and the general population was compared by following their medical histories. RESULTS: The cumulative incidence rate of CTS among dentists was 0.5% during the 5-year follow-up period. In dentists, the risk was higher in women (women: 0.7%; men: 0.4%) and older individuals (≥60 years: 1.0%; <60 years: 0.4%). After adjusting for age, sex, and underlying comorbidities, dentists had a lower risk of CTS than the general population (adjusted odds ratio [AOR]: 0.65, 95% confidence interval [CI]: 0.45-0.92). Dentists had a higher risk for CTS compared with non-dentist HCPs, although the difference was not statistically significant (AOR: 1.21; 95% CI: 0.90-1.64). CONCLUSIONS: In CTS, dentists had a lower risk than the general population and a trend of higher risk than non-dentist HCPs. The difference between dentists and non-dentist HCPs suggests that we should pay attention to dentists for potential occupational risk of this disease. However, further studies are warranted to better clarify it.

Citation Characteristics of H-Classics Articles in Implant Dentistry: A Citation Analysis Using H-Classics Method.

PURPOSE: Citation-based metrics, such as the H-classics method, have been used as an indicator to assess academic performance in the scientific community. However, information addressing issues regarding self-citation, citation half-life, and subject area of origin in implant dentistry is lacking. The purpose of this study was to investigate the citation characteristics of H-classics articles in implant dentistry throughout different time periods. MATERIALS AND METHODS: H-classics implant dentistry articles were searched and selected by applying the H-classics method from the Scopus database. Bibliometric analysis was conducted to evaluate the citation characteristics, including institutional and journal self-citation, citation half-life, and subject area of origin of identified H-classics articles. RESULTS: The International Journal of Oral & Maxillofacial Implants and Clinical Oral Implants Research are the leading journals contributing the majority of citations to the retrieved H-classics articles. Articles published in the United States cited the most H-classics articles. Journal self-citation was 12.41% on average, while institutional self-citation was approximately 7.81%. Citation half-life decreased significantly across time periods, with an average decreasing ratio of 43.95%. Research on Scope III, bioengineering interventions, had the most prominent distribution citation frequency in the subject area "Others." CONCLUSION: This study provides insightful views regarding citation characteristics of H-classics articles in implant dentistry (eg, interdisciplinary publications on bioengineering interventions) during the investigation periods, which may foster the translation of preclinical research into clinical applications in the future.

Association between the presence of distolingual root in mandibular first molars and the presence of C-shaped mandibular second molars: a CBCT study in a Taiwanese population.

OBJECTIVES: The purpose of this study was to assess the prevalence of C-shaped canals in permanent mandibular second molars (SMs) and to determine whether its appearance was associated with the presence of distolingual root (DLR) in permanent mandibular first molars (FMs). METHOD AND MATERIALS: Three hundred and eighty patients were qualified for evaluation of their FMs and SMs using cone beam computed tomography. The prevalence, distribution pattern, external root morphology, and the internal root canal anatomy of the examined molars were recorded and analyzed. Furthermore, the association between the root canal configurations of SMs and the appearance of DLR in FMs was also assessed. RESULTS: The prevalence of SMs with C-shaped root canals was 44.7%. The most common root canal configuration type of the one-rooted SMs with C-shaped anatomy was C3 (45.6%), followed by C2 and C1. The frequency of C-shaped canals in SMs was 45.4% in Non-DLR group, 52.8% in unilateral DLR group, and 33.9% in bilateral DLR group, respectively. Moreover, the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was significantly lowered. CONCLUSION: The association between the presence of DLR in FMs and C-shaped canal configurations in neighboring SMs was surveyed, and the prevalence of C-shaped root canals in SMs with the presence of bilateral DLRs in FMs was found to be significantly lowered.

Synthesis and Characterization of Melatonin-Loaded Chitosan Microparticles Promote Differentiation and Mineralization in Preosteoblastic Cells.

In terms of a novel scaffold with well good osteoinductive and osteoconductive capacity, melatonin (Mel) possesses positive effects on chemical linkage in scaffold structures, which may allow osteogenic differentiation. The aim of this study is to fabricate Mel-loaded chitosan (CS) microparticles (MPs) as a novel bone substitute through generating a Mel sustained release system from Mel-loaded CS MPs and evaluating its effect on the osteogenic capacity of MC3T3-E1 in vitro. The physical-chemical characteristics of the prepared CS MPs were examined by both Fourier transform infrared spectroscopy and scanning electron microscopy. The released profile and kinetics of Mel from MPs were quantified, and the bioactivity of the released Mel on preosteoblastic MC3T3-E1 cells was characterized in vitro. An in vitro drug release assay has shown high encapsulation efficiency and sustained release of Mel over the investigation period. In an osteogenesis assay, Mel-loaded CS MPs have significantly enhanced alkaline phosphatase (ALP) mRNA expression and ALP activity compared with the control group. Meanwhile, the osteoblast-specific differentiation genes, including runt related transcription factor 2 (Runx2), bone morphogentic protein-2 (Bmp2), collagen I (Col I), and osteocalcin (Ocn), were also significantly upregulated. Furthermore, quantificational alizarin red-based assay demonstrated that Mel-loaded CS MPs notably enhanced the calcium deposit of MC3T3-E1 compared with controls. In essence, Mel-loaded CS MPs can control the release of Mel for a period of time to accelerate osteogenic differentiation of preosteoblast cells in vitro.

Increasing prominence of implantology research: a chronological trend analysis of 100 top-cited articles in periodontal journals.

PURPOSE: To identify 100 top-cited articles published in periodontal journals and analyse the research trends by using citation analysis. MATERIALS AND METHODS: 100 top-cited articles published in periodontal journals were retrieved by searching the database of the ISI Web of Science and Journal Citation reports. For each article, the following principal bibliometric parameters: authorship, geographic and institute origin, manuscript type, study design, scope of study, and citation count of each time period were analysed from 1965 to 2015. RESULTS: The identified 100 top-cited articles were retrieved from five periodontal journals and citation counts were recorded between 262 and 1,693 times. For the institute of origin, the most productive institute, in terms of the number of 100 top-cited articles published, was the University of Gothenburg (Sweden) (n = 19), followed by the Forsyth Dental Center (USA) (n = 15). Most manuscripts were original research (n = 74), and the inflammatory periodontal disease (n = 59) was the most frequent topic studied. Interestingly, the trend of increase average citation reached significance for implantology (ß = 26.75, P = 0.003) and systemic interactions (ß = 29.83, P = 0.005), but not for inflammatory disease (ß = -10.30, P = 0.248) and tissue regeneration (ß = 9.04, P = 0.081). By using multivariable linear regression in a generalised linear model, suitable published journal (Journal of Clinical Periodontology), geographic regions (Europe), more intense international collaboration, adequate manuscript type (review article) and study design (systematic review) could be attributed to escalating average citation counts in implantology (all P < 0.05). However, for systemic interactions, only geographic region and study design were significantly associated with the increasing citation trend. CONCLUSIONS: These principal bibliometric characteristics revealed escalated trends in average citation count in implantology throughout time.

Prevalence of Dental Implants and Evaluation of Peri-implant Bone Levels in Patients Presenting to a Dental School: A Radiographic Cross-Sectional 2-Year Study.

PURPOSE: To evaluate the number of patients with dental implants who present to a dental school clinic for screening and to report the prevalence of peri-implant bone level change detected on digital panoramic radiographs of those subjects. MATERIALS AND METHODS: Patient screening files for 9,422 patients over a 2-year period were examined to see how many patients presented with dental implants. Those patients with at least one implant were further evaluated by measuring the bone level on the mesial and distal sides of the implant using the screening radiograph. RESULTS: A total of 187 patients (2%) had at least one implant. In regard to implants, 423 were examined and 146 (33%) had no detectable bone loss defined as bone level below the top of the implant. When thresholds of bone loss were evaluated, 109 implants (25%) had ≥ 2 mm of bone loss on either the mesial or distal sides or both. The median bone loss was 1.74 mm for the 277 implants with detectable bone loss and 2.97 mm for the 109 implants that had ≥ 2 mm bone loss. Interestingly, patients who were ≥ 70 years of age had significantly (P = .03) more bone loss in the mandible compared with the maxilla, while patients who were 60 to 69 years of age had significantly greater loss in the maxilla. CONCLUSION: These data reveal that for patients presenting to the dental school for a screening over a 2-year period, 1.98% had one or more dental implants. Furthermore, those patients with implants had a minimum amount of bone loss as measured from the top of the implant.

A lateral ridge augmentation study to evaluate a synthetic membrane for guided bone regeneration: an experiment in the canine mandible.

OBJECTIVES: To evaluate guided bone regeneration outcomes in defects protected with an in situ formed polyethylene glycol (PEG) hydrogel membrane as compared to a non-cross-linked collagen membrane (CM). MATERIAL AND METHODS: Four mandibular alveolar ridge defects were created in eight hound dogs. Regenerative procedures were randomly allocated to one of four groups consisting of freeze-dried bone allograft, which is referred to in this study as freeze-dried bone xenograft (FDBX) + PEG, autogenous bone (AB) + PEG, AB + CM, and AB alone. After 8 weeks, titanium dental implants were placed into augmented sites. After 8 weeks of allowed time for osseointegration, the animals were sacrificed to harvest block specimens for bone-to-implant contact (BIC) and ridge width histomorphometric analysis. RESULTS: Polyethylene glycol membranes had an exposure rate of 50% as compared to 12.5% for sites grafted with CM. Regenerative outcomes with respect to implant placement were least favorable for FDBX + PEG which had implants placed in 37.5% of augmented sites compared to 100% implant placement for all other groups. No statistically significant differences were noted between groups for ridge width measurements in implant and non-implant histologic sections (P > 0.05). Buccal BIC (%) values between treatment groups also failed to reach statistical significant difference (FDBX + PEG [60.2 ± 9.4]; AB + PEG [58.8 ± 8.5]; AB + CM [57.9 ± 12.8]; AB [61.0 ± 10.2]). CONCLUSION: When used in conjunction with FDBX, PEG had unpredictable bone formation and in most cases negatively impacted future implant placement.

Preoperative assessment of labial bone perforation for virtual immediate implant surgery in the maxillary esthetic zone: A computer simulation study.

BACKGROUND: In this computer simulation study, the authors investigated the frequency distribution of labial bone perforation (LBP) between various sagittal root position (SRP) classes with respect to the anterior maxillary osseous housing and evaluated the associated factors correlated with a higher risk of LBP when performing a virtual immediate implant surgery in the esthetic zone. METHODS: The authors analyzed cone-beam computed tomography (CBCT) images from 285 qualified study participants (1,449 teeth) to determine the probability of LBP when associated with selected variables, such as tooth type, SRP class, and morphologic parameters. The authors examined associated factors and analyzed the adjusted odds ratios by means of multiple logistic regression analysis. RESULTS: The overall probability of LBP was 81.7%, which presented statistically significant differences between each specific tooth type and SRP class (all P<.001). After adjusting for other factors, the authors found that the maxillary central incisor was 2.37 times more likely to have LBP than the canine. SRP class I was 4.9 times more likely to be associated with LBP when compared with SRP class IV. CONCLUSIONS: When a clinician performs an immediate implant in the anterior esthetic zone, he or she should be aware that the specific tooth type, SRP class, and morphologic features of fossa concavities are associated with a risk of experiencing LBP. PRACTICAL IMPLICATIONS: Presurgical cross-sectional images can be analyzed to identify anatomic features relative to LBP in the maxillary esthetic region, and this can avoid unpleasant complications, specifically when performing immediate implant procedures.

Risk of lingual plate perforation for virtual immediate implant placement in the posterior mandible: A computer simulation study.

BACKGROUND: This study sought to determine which factors are correlated to a higher risk of lingual plate perforation (LPP) when placing a virtual implant in the area of the anticipated extraction site of the posterior mandible. METHODS: Computed tomographic images of 300 patients (1,279 teeth) were analyzed in regard to the shape of the mandible (convergent, parallel, or undercut type), dimensional parameters of lingual concavity (angle, height, depth) and its relation to the inferior alveolar canal (zones A, B, C), distance from root apex to inferior alveolar canal, and probability of LPP. The odds ratio of variables was determined by multiple logistic regression modeling. RESULTS: The overall probability of LPPs on virtual implant placement was 3.1%. This perforation was most commonly observed at the second molar and with a U-type ridge. After adjusting cofounders, a concave point located in zone A is 17.34 times more likely to have a LPP than one in zone C. The probability of LPPs was reduced by 34% for every 1-millimeter increase in distance from root apex to inferior alveolar canal on virtual implant placement of posterior mandible region. CONCLUSIONS: Three-dimensional cone-beam computed tomographic imaging is essential for planning immediate implant placement in the anticipated extraction sites of the posterior mandible region as proved by anatomic findings that can only be understood from preoperative imaging analysis. PRACTICAL IMPLICATIONS: Presurgical cross-sectional images can be analyzed to identify anatomic features relative to the lingual concavities in the posterior mandible region, which can help to avoid unpleasant complications, specifically when performing immediate implant procedures.

Risk assessment of inferior alveolar nerve injury for immediate implant placement in the posterior mandible: a virtual implant placement study.

OBJECTIVES: To investigate the prevalence and morphological parameters of lingual concavity, and whether these factors are related to a higher risk of inferior alveolar nerve (IAN) injury when performing an immediate implant surgery in posterior mandible region. METHODS: The CBCT images from 237 subjects (1008 teeth) were analysed the shape of the mandibles (C, P, U type), dimensional parameters of lingual concavity (angle, height, depth), and its relation to inferior alveolar canal (IAC) (A, B, C zone), RAC (distance from root apex to IAC) and probability of IAN injury. Multiple logistic regression modelling to determine the odds ratio of variables that made an important contribution to the probability of IAN injury and to adjust for confounding variables. RESULTS: The U type ridge (46.7%) and the most concave point located at C zone (48.8%) are most prevalent in this region. The mandibular second molar presents highest risk for IAN injury than other tooth type (p<0.001), which were 3.82 times to occur IAN injury than the mandibular second premolar. The concave point located at A zone and B zone were 7.82 and 3.52 times than C zone to have IAN damage, respectively. The probability of IAN injury will reduce 26% for every 1mm increase in RAC (p<0.001). CONCLUSIONS: The tooth type, morphological features of lingual concavities, and RAC are associated with risks of IAN injury during immediate implant placement. CLINICAL SIGNIFICANCE: Pre-surgical mapping of the IAC and identification of its proximity relative to the lingual concavity in the posterior mandible regions may avoid unpleasant complications, specifically when performing immediate implant procedures.

Concomitant horner and harlequin syndromes after inferior alveolar nerve block anesthesia.

INTRODUCTION: Intraoral anesthesia is probably the most commonly used procedure in dentistry. METHODS: Although inferior alveolar nerve block (IANB) anesthesia is one of the safest procedures to anesthetize the mandibular teeth, side effects of IANB anesthesia can still give rise to potential risks for patients. Fortunately, most observed alterations are transient and self-limited. RESULTS: The complications of IANB anesthesia are varied in nature and could be specifically categorized into systemic, localized, and distant complications. When the complications occur around the orofacial structures including the temporomandibular joint, middle ear, facial skin, and the eye, which are away from the oral cavity, it can be defined as distant complications. However, to our best knowledge, the concomitant occurrence of neurologic phenomena such as Horner syndrome combined with cutaneous complications in a patient receiving IANB anesthesia has never been discussed. CONCLUSIONS: In this exceptional case, the unusual Horner syndrome manifestations related to unilateral ptosis, miosis, and anisocoria were simultaneously developed with skin ischemia, paresthesia, and asymmetric flushing after the administration of IANB anesthesia.

Soft and hard tissue histologic dimensions around dental implants in the canine restored with smaller-diameter abutments: a paradigm shift in peri-implant biology.

PURPOSE: To evaluate the biologic width dimensions around implants with nonmatching implant-abutment diameters. MATERIALS AND METHODS: Five canines had their mandibular premolars and first molars removed bilaterally and replaced with 12 implants that had nonmatching implant-abutment diameters. On one side, six implants were placed in a submerged surgical approach, and the other side utilized a nonsubmerged approach. Two of the implants on each side were placed either 1 mm above, even with, or 1 mm below the alveolar crest. Two months later, gold crowns were attached, and the dogs were sacrificed 6 months postloading. Block sections were processed for histologic and histomorphometric analyses. RESULTS: The bone level, connective tissue length, epithelial dimension, and biologic width were not significantly different when the implants were initially placed in a submerged or nonsubmerged surgical approach. The bone level was significantly different around implants placed 1 mm above the crest compared to implants placed even with or 1 mm below the alveolar crest. The connective tissue dimension was not different for any implant level placement. The epithelial dimension and biologic width were significantly greater for implants placed 1 mm below the alveolar crest compared to implants placed even with or 1 mm above the alveolar crest. For five of six implant placements, connective tissue covered the implant/abutment interface. CONCLUSIONS: This study reveals a fundamental change in the biologic response to implants with nonmatching implant-abutment diameters. Unlike implants with matching implant-abutment diameters, the connective tissue extended coronally past the interface (microgap). This morphologic tissue alteration represents a significant change in the biologic reaction to implant-abutment interfaces and suggests that marginal inflammation is eliminated or greatly reduced in these implant designs.

Factors affecting treatment decisions and outcomes of root-resected molars: a nationwide study.

BACKGROUND: Treatment of furcation-involved molars presents a clinical challenge. This study retrospectively investigates the demographic parameters affecting treatment decisions and outcomes of root-resected molars using a nationwide population-based dataset. METHODS: De-identified data from 471 eligible patients were obtained from a representative cohort composed of 1 million of Taiwan's population. Demographic factors that influence treatment decisions and outcomes of root-resected teeth were examined. Cox regression was performed to statistically analyze the factors. RESULTS: The overall survival rate for root-resected molars was 91.1%. The survival times of the extracted and surviving teeth were 303.0 ± 274.6 and 551.8 ± 327.2 days, respectively (P <0.001). The analyzed patient-related factors, such as living district, urbanization level, medical institution, and monthly income, have remarkable influence on treatment decisions; however, there is no statistically significant difference in survival rate between root-resected molars receiving flap surgery and those that do not (P = 0.504). After adjusting for other factors, patients aged >74 years have 3.33 times (hazard ratio = 3.33; 95% CI = 1.04 to 10.66; P = 0.043) higher rates of molar extraction than younger counterparts. CONCLUSIONS: The overall survival rate of root-resected molars was satisfactory. Patients with advanced age (>74 years) had a higher risk of extraction occurrence on resected molars. Patient-related factors may influence the treatment decision of whether molars receive flap surgery. These findings suggest that demographic factors should be carefully evaluated before and after performing root-resection procedures because these factors may eventually impact the outcome of root-resected molars.

Biological complication in guided bone regeneration with a polylactic acid membrane: a case report.

PURPOSE: This case report describes a biologic complication related to polylactic acid membrane in guided bone regeneration (GBR). MATERIALS AND METHODS: A healthy 42-year-old patient complained of persistent discomfort of the maxillary anterior gingiva. Clinical examination and radiographs showed severe periodontal destruction of teeth 7 through 10. Teeth extraction was followed by early implant placement with GBR. RESULTS: Four months later, severe bone resorption was observed upon surgical exposure. A second GBR was performed. Wound healing progressed uneventfully and an implant-supported fixed partial denture was later loaded. CONCLUSION: We presume that this complication was a foreign body reaction to the polylactic acid membrane. Such a reaction can affect soft and hard tissue healing following GBR. Long-term follow-up is needed to determine stability of the results.