A novel digital altered cast impression technique for fabricating a removable partial denture with a distal extension

BackgroundAlthough computer-aided design and computer-aided manufacturing has been successfully used in fabricating removable partial dentures (RPDs), making altered cast impressions is still a time-consuming and labor-intensive process for fabricating RPDs with a distal extension. An alternative digital technique has been developed to simplify this process.MethodsThe authors present a case in which they sought to improve the efficiency and simplicity in obtaining altered cast impressions by means of digital technology. Initially, a primary plaster cast was scanned as a digital cast. Based on the digital cast, a novel custom tray was designed and fabricated using a 3-dimensional printing method. With the custom tray, the novel altered cast impression was fabricated and scanned, and the final virtual altered cast was reconstructed by a stitching method.ResultsBased on the virtual altered cast, the authors designed the virtual RPD framework. Finally, the titanium alloy framework was fabricated using a 3-dimensional printing process, and the authors fit the final RPD to the patient.ConclusionsThis novel digital altered cast impression technique may eliminate interoperator variability and increase precision compared with the traditional technique.Practical ImplicationsThis technique showed the potential for reducing clinical appointments, chair time, and laboratory procedures.     

Comparison of treatment outcomes and time efficiency between a digital complete denture and conventional complete denture: A pilot study

BackgroundThe authors of this study aimed to compare the treatment outcomes and time efficiency between digital and conventional complete denture restorations and propose suggestions for clinical use.MethodsThe authors used digital (functionally suitable digital complete denture [FSD]) and conventional complete denture restorations to make 2 dentures each for 10 edentulous patients. All the operations of both techniques before denture delivery were completed in the first 4 visits, and then 2 dentures were delivered successively for the patients. The clinical and laboratory times were recorded to evaluate the time efficiency; treatment outcomes were evaluated via scoring the denture satisfaction of the dentist and patients in a double-blind manner.ResultsThe satisfaction scores of FSDs (7.6-9.6 [dentist's scores], 8.4-10 [patients' scores]) were higher than those of conventional dentures (7.2-9.7 [dentist's score], 7.4-9.8 [patients' scores]), but there were no significant differences. The clinical and laboratory operation times of the FSD group were less than those of the conventional group, saving an average of 28.0 minutes and 64.3 minutes in the clinic and laboratory, respectively.ConclusionsFSD technology can improve the efficiency of clinical and laboratory operations and shorten the manufacturing cycle of dentures. The occlusion stability of FSDs was statistically better than that of traditional dentures, but there was no statistical difference in other clinical indicators.Practical ImplicationsFSD technology is low cost and easy to operate and has several applications. Compared with conventional complete denture restoration technology, FSDs can save time and have a comparable clinical effect.This clinical trial was registered at the Chinese Clinical Trial Registry. The registration number is ChiCTR1900021722.     

Management of painful temporomandibular disorders: Methods and overview of The National Dental Practice-Based Research Network prospective cohort study

BackgroundPatients often seek consultation with dentists for temporomandibular disorders (TMDs). The objectives of this article were to describe the methods of a large prospective cohort study of painful TMD management, practitioners’ and patients’ characteristics, and practitioners’ initial treatment recommendations conducted by The National Dental Practice-Based Research Network (the “network”).MethodsParticipating dentists recruited into this study treated patients seeking treatment for painful TMDs. The authors developed self-report instruments based on well-accepted instruments. The authors collected demographics, biopsychosocial characteristics, TMD symptoms, diagnoses, treatments, treatment adherence, and painful TMDs and jaw function outcomes through 6 months.ResultsParticipating dentists were predominately White (76.8%) and male (62.2%), had a mean age of 52 years, and were general practitioners (73.5%) with 23.8% having completed an orofacial pain residency. Of the 1,901 patients with painful TMDs recruited, the predominant demographics were White (84.3%) and female (83.3%). Patients’ mean age was 44 years, 88.8% self-reported good to excellent health, and 85.9% had education beyond high school. Eighty-two percent had pain or stiffness of the jaw on awakening, and 40.3% had low-intensity pain. The most frequent diagnoses were myalgia (72.4%) and headache attributed to TMDs (51.0%). Self-care instruction (89.4%), intraoral appliances (75.4%), and medications (57.6%) were recommended frequently.ConclusionsThe characteristics of this TMD cohort include those typical of US patients with painful TMDs. Network practitioners typically managed TMDs using conservative treatments.Practical ImplicationsThis study provides credible data regarding painful TMDs and TMD management provided by network practitioners across the United States. Knowledge acquired of treatment recommendations and patient reports may support future research and improve dental school curricula.     

Local accuracy of actual intraoral scanning systems for single-tooth preparations in vitro

BackgroundThe authors evaluated the local accuracy of intraoral scanning (IOS) systems for single-tooth preparation impressions with an in vitro setup.MethodsThe authors digitized a mandibular complete-arch model with 2 full-contour crowns and 2 multisurface inlay preparations with a highly accurate reference scanner. Teeth were made from zirconia-reinforced glass ceramic material to simulate toothlike optical behavior. Impressions were obtained either conventionally (PRESIDENT, Coltène) or digitally using the IOS systems TRIOS 3 and TRIOS 3 using insane scan speed mode (3Shape), Medit i500, Version 1.2.1 (Medit), iTero Element 2, Version 1.7 (Align Technology), CS 3600, Version 3.1.0 (Carestream Dental), CEREC Omnicam, Version 4.6.1, CEREC Omnicam, Version 5.0.0, and Primescan (Dentsply Sirona). Impressions were repeated 10 times per test group. Conventional (CO) impressions were poured with type IV gypsum and digitized with a laboratory scanner. The authors evaluated trueness and precision for preparation margin (MA) and preparation surface (SU) using 3-dimensional superimposition and 3-dimensional difference analysis method using (95% – 5%) / 2 percentile values. Statistical analysis was performed using Kruskal-Wallis test. Results were presented as median (interquartile range) values in micrometers.ResultsThe authors found statistically significant differences for MA and SU among different test groups for both trueness and precision (P < .05). Median (interquartile range) trueness values ranged from 11.8 (2.0) μm (CO) up to 40.5 (10.9) μm (CEREC Omnicam, Version 5.0.0) for SU parameter and from 17.7 (2.6) μm (CO) up to 55.9 (15.5) μm (CEREC Omnicam, Version 5.0.0) for MA parameter.ConclusionsIOS systems differ in terms of local accuracy. Preparation MA had higher deviations compared with preparation SU for all test groups.Practical implicationsTrueness and precision values for both MA and SU of single-unit preparations are equal or close to CO impression for several IOS systems.     

Antibiotics for the urgent management of symptomatic irreversible pulpitis,symptomatic apical periodontitis,and localized acute apical abscess: Systematic review and meta-analysis—a report of the American Dental Association

BackgroundPatients with pulpal and periapical conditions often seek treatment for pain, intraoral swelling, or both. Even when definitive, conservative dental treatment (DCDT) is an option, antibiotics are often prescribed. The purpose of this review was to summarize available evidence regarding the effect of antibiotics, either alone or as adjuncts to DCDT, to treat immunocompetent adults with pulpal and periapical conditions, as well as additional population-level harms associated with antibiotic use.Type of Studies ReviewedThe authors updated 2 preexisting systematic reviews to identify newly published randomized controlled trials. They also searched for systematic reviews to inform additional harm outcomes. They conducted searches in MEDLINE, Embase, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature. Pairs of reviewers independently conducted study selection, data extraction, and assessment of risk of bias and certainty in the evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach.ResultsThe authors found no new trials via the update of the preexisting reviews. Ultimately, 3 trials and 8 additional reports proved eligible for this review. Trial estimates for all outcomes suggested both a benefit and harm over 7 days (very low to low certainty evidence). The magnitude of additional harms related to antibiotic use for any condition were potentially large (very low to moderate certainty evidence).Conclusions and Practical ImplicationsEvidence for antibiotics, either alone or as adjuncts to DCDT, showed both a benefit and a harm for outcomes of pain and intraoral swelling and a large potential magnitude of effect in regard to additional harm outcomes. The impact of dental antibiotic prescribing requires further research.     

Association between rs11362 polymorphism in the beta-defensin 1 (DEFB1) gene and dental caries: A meta-analysis

ObjectivesBeta-defensin 1, encoded by the DEFB1 gene, is an important molecule that confers protection from dental caries. Numerous studies have been conducted on the rs11362 polymorphism in the DEFB1 gene. We evaluated the results from studies that have investigated the association between rs11362 polymorphism and dental caries, through a meta-analysis.MethodsThis meta-analysis was designed according to the PRISMA statement guideline. Electronic databases (PubMed, Web of Science, Scopus, and Cochrane Library) were scanned by two independent researchers. The publication bias was determined by statistical analyses using funnel plot, Egger regression test, and Begg and Mazumdar rank correlation test. Heterogeneity was evaluated using the chi-square test, tau-square, and Higgins I² test. Odds ratio (OR) was used to measure the effect size.ResultsRank correlation and regression procedures showed the absence of publication bias in the meta-analysis (p > 0.05). The DEFB1 rs11362 polymorphism in the heterozygous (CC vs. CT: OR = 2.20, 95% confidence interval (CI): 1.17, 4.10; p = 0.014) and dominant (CC vs. CT + TT: OR = 3.11, 95% CI: 1.18, 8.21; p = 0.022) models in the permanent dentition subgroup showed significant differences. However, there was no significant difference between any model in either the deciduous dentition (p > 0.05) or the mixed dentition subgroups (p > 0.05).ConclusionsThis meta-analysis suggests that the DEFB1 rs11362 polymorphism is associated with dental caries in permanent dentition. Moreover, individuals with the TT genotype were found to have seven times higher risk of dental caries than individuals with the CC genotype. There was no such association or statistical difference observed for deciduous and mixed dentitions.     

A clinical investigation of dental evacuation systems in reducing aerosols

BackgroundThe route of transmission of severe acute respiratory syndrome coronavirus 2 has challenged dentistry to improve the safety for patients and the dental team during various treatment procedures. The purpose of this study was to evaluate and compare the effectiveness of dental evacuation systems in reducing aerosols during oral prophylactic procedures in a large clinical setting.MethodsThis was a single-center, controlled clinical trial using a split-mouth design. A total of 93 student participants were recruited according to the inclusion and exclusion criteria. Aerosol samples were collected on blood agar plates that were placed around the clinic at 4 treatment periods: baseline, high-volume evacuation (HVE), combination (HVE and intraoral suction device), and posttreatment. Student operators were randomized to perform oral prophylaxis using ultrasonic scalers on 1 side of the mouth, using only HVE suction for the HVE treatment period and then with the addition of an intraoral suction device for the combination treatment period. Agar plates were collected after each period and incubated at 37 °C for 48 hours. Colony-forming unit (CFU) counts were determined using an automatic colony counter.ResultsThe use of a combination of devices resulted in significant reductions in CFUs compared with the use of the intraoral suction device alone (P < .001). The highest amounts of CFUs were found in the operating zone and on patients during both HVE and combination treatment periods.ConclusionsWithin limitations of this study, the authors found significant reductions in the amount of microbial aerosols when both HVE and an intraoral suction device were used.Practical ImplicationsThe combination of HVE and intraoral suction devices significantly decreases microbial aerosols during oral prophylaxis procedures.     

Development of dentition: From initiation to occlusion and related diseases

BackgroundThe development of dentition begins in the embryonic oral cavity and progresses in the branchial arches and alveolar bone. Continuous cellular and molecular crosstalk occurs during crown formation, after which the tooth germ begins to migrate apically through the alveolar process into the oral cavity. It eventually comes in contact with its antagonist in the contralateral jaw to establish functional occlusion. Any defect in either step can result in delayed tooth development, the spectrum of which varies from a congenitally missing tooth to an impacted tooth (infraocclusion) with an eruption problem, both of which can impair oral function.HighlightCongenitally missing teeth or eruption problems may result from genetic mutations. Several different mutations have been identified, each causing a distinct phenotype. Thus, it is imperative that medical providers understand the fundamentals of these genetic principles that govern such dental diseases.ConclusionIn this review, we focus on several diseases, including congenitally missing teeth and tooth eruption problems. We review these diseases with aspect to their association with a particular syndrome, as well as independently in a non-syndromic capacity. We also review previously identified genetic mutations and discuss the possible mechanisms that cause individual phenotypes by analyzing previous investigations. We also discuss future prospects of how genetic diagnosis and precision medicine could impact the clinical environment in the field of dentistry.Ethical approvalPresent study has been carried out in accordance with The Code of Ethics of the World Medical Association and approved by Institutional Review Board of Osaka University Graduate School of Dentistry.     

Understanding the pathophysiology of sleep bruxism based on human and animal studies: A narrative review

BackgroundSleep bruxism (SB) is a common sleep disorder that affects approximately 20% of children and 10% of adults. It may cause orodental problems, such as tooth wear, jaw pain, and temporal headaches. However, the pathophysiological mechanisms underlying SB remain largely unknown, and a definitive treatment has not yet been established.HighlightHuman studies involving polysomnography have shown that rhythmic masticatory muscle activity (RMMA) is more frequent in otherwise healthy individuals with SB than in normal individuals. RMMA occurs during light non-rapid eye movement (non-REM) sleep in association with transient arousals and cyclic sleep processes. To further elucidate the neurophysiological mechanisms of SB, jaw motor activities have been investigated in naturally sleeping animals. These animals exhibit various contractions of masticatory muscles, including episodes of rhythmic and repetitive masticatory muscle bursts that occurred during non-REM sleep in association with cortical and cardiac activation, similar to those found in humans. Electrical microstimulation of corticobulbar tracts may also induce rhythmic masticatory muscle contractions during non-REM sleep, suggesting that the masticatory motor system is activated during non-REM sleep by excitatory inputs to the masticatory central pattern generator.ConclusionThis review article summarizes the pathophysiology of SB based on the findings from human and animal studies. Physiological factors contributing to RMMA in SB have been identified in human studies and may also be present in animal models. Further research is required to integrate the findings between human and animal studies to better understand the mechanisms underlying SB.     

The influence of age and orthodontic debonding on the prevalence and severity of enamel craze lines

BackgroundCraze lines may cause esthetic concerns, especially when noted on the incisors. Various light sources with additional recording apparatus have been proposed to visualize craze lines, but a standardized clinical protocol is yet to be determined. This study aimed to validate the application of near-infrared imaging (NIRI) from intraoral scans to evaluate craze lines and to determine the influence of age and orthodontic debonding on their prevalence and severity.MethodsThe NIRI of maxillary central incisors from a full-mouth intraoral scan and photographs from an orthodontic clinic (N = 284) were collected. The prevalence of craze lines and influence of age and orthodontic debonding history on severity were evaluated.ResultsCraze lines were detected reliably as white lines distinguishable from dark enamel using the NIRI from intraoral scans. The craze line prevalence was 50.7%, which was significantly higher in patients 20 years or older than in patients younger than 20 years (P < .001), with more frequent severe craze lines for those 40 years or older than in patients younger than 30 years (P < .05). Prevalence or severity was similar between patients with and without an orthodontic debonding history regardless of the type of appliance.ConclusionThe prevalence of craze lines in the maxillary central incisor was 50.7%, with a higher prevalence in adults than in adolescents. Orthodontic debonding did not affect the severity of craze lines.Practical ImplicationsCraze lines were reliably detected and documented by means of applying NIRI from intraoral scans. Intraoral scanning can provide new clinical information on enamel surface characteristics.     

Association between metabolic syndrome and tooth loss: A systematic review and meta-analysis

BackgroundThe authors conducted a systematic review and meta-analysis to verify the existence and level of scientific evidence concerning the association between metabolic syndrome (MetS), as the main exposure, and tooth loss (TL), as the outcome.Types of Studies ReviewedThrough electronic databases and partially through gray literature, the authors identified observational studies in adults. The authors used no date or language restrictions. The authors evaluated the studies’ methodological quality by using the Newcastle-Ottawa Scale. The authors conducted a random-effects model meta-analysis. The authors assessed the quality of evidence by using the Grading of Recommendations Assessment, Development and Evaluation criteria.ResultsTwelve studies met the eligibility criteria, and 9 were retained for the meta-analysis. Most were cross-sectional studies with good methodological quality. Participants with MetS had fewer teeth (standardized mean difference, −2.77; 95% confidence interval, −4.56 to −0.98) and an increased likelihood of lacking functional dentition (odds ratio, 2.37; 95% confidence interval, 1.89 to 2.96) than did those without MetS. The overall quality of evidence was very low.Conclusions and Practical ImplicationsBetter-conducted longitudinal studies are necessary to establish a causal relationship between MetS and TL to inform the best strategies to prevent TL in populations with MetS.     

Prophylactic antibiotic regimens in dental implant failure: A systematic review and meta-analysis

BackgroundIn this systematic review and meta-analysis, the authors examine the efficacy of antibiotic prophylaxis (AP) and specific antibiotic regimens for prevention of dental implant failure in patients who are healthy overall.Types of Studies ReviewedThe authors independently conducted electronic database and manual searches to identify randomized controlled trials (RCTs). The authors selected articles on the basis of eligibility criteria and assessed for risk of bias by using the Cochrane Handbook. Implant failure was the primary outcome studied; perimucositis or implantitis, prosthetic failure, and adverse events were secondary outcomes studied. The authors conducted random effects meta-analysis for risk ratios of dichotomous data and used OpenMeta[Analyst] (Center for Evidence Synthesis, Brown School of Public Health) for qualitative assessment of administration schedules.ResultsWith duplicates removed, the authors screened 1,022 abstracts, reviewed 21 full-text articles, and included 8 RCTs that included 2,869 implants in 1,585 patients. Meta-analysis results indicated that AP resulted in a statistically significantly lower number of implant failures for all regimens combined (implant, P = .005; patient, P = .002), as well as preoperative (implant, P = .01; patient, P = .007), pre- and postoperative (implant, P = .04), and postoperative AP only (implant, P = .02), compared with no antibiotics. The authors found no statistically significant differences in analysis of comparative antibiotic treatments or secondary outcomes. The authors identified confounding variables.Conclusions and Practical ImplicationsAlthough meta-analysis results suggested that AP may reduce implant failure, definitive conclusions cannot be achieved yet. The overall nonsignificant differences reported in individual trials, limitations discussed, implant infection outcomes, and antibiotic-associated risks must be considered. Thus, the results for implant failure outcomes may not warrant the indiscriminate use of antibiotics in patients who are healthy who are receiving dental implants. Investigators must conduct large-scale RCTs to determine the efficacy of AP and various regimens, independent of confounding variables.     

Buccal bifurcation cyst: A case series and review of the literature

IntroductionBuccal bifurcation cyst is an inflammatory odontogenic cyst and constitutes up to 5% of all odontogenic cysts. The aim of this study was to report a series of cases, review the recent literature, and facilitate recognition and proper treatment of this entity.MethodsWith institutional review board approval, the authors retrieved all archival cases of buccal bifurcation cyst from the oral pathology biopsy service from 1994 through 2018. Patient age and sex, cyst location, clinician’s impression, radiographic appearance, diagnosis, and treatment data were recorded.ResultsA total of 10 cases were identified. Average patient age was 9 years. A slight male predilection was observed (n = 6, 60%). One hundred percent of cases were in the mandible, including 3 (30%) bilateral cases.ConclusionsMandibular buccal bifurcation cyst is an important entity in pediatric patients but may be less likely to be recognized by clinicians not regularly treating children. The results of this study are mostly consistent with the literature. Treatment is typically via enucleation or even more conservative modalities, and extraction should be avoided if possible.Practical ImplicationsBuccal bifurcation cysts should be treated via enucleation or even more conservative methods. If possible, the affected teeth should be preserved.     

National and international guidelines on the replacement of missing teeth with dentures for head and neck cancer patients post-radiotherapy: A rapid review

BackgroundReplacement of missing teeth is not a straightforward task in head and neck cancer (HNC) patients post-radiotherapy. There is debate regarding the best way to care for these patients as it has been reported that using dentures by HNC patients after receiving treatment with radiotherapy might initiate the development of osteoradionecrosis.AimThis rapid review aimed to collate and compare the national and international guidelines for the use of dentures following radiotherapy for HNC patients.Materials and methodsThree steps were included in data collection of this rapid review (first step; identification of dental and relevant non-dental associations/societies, second step, identification of national and international guidelines regarding the dental management of HNC patients, and third step; identification of recommendations about the replacement of missing teeth in HNC patients).ResultsIn the 193 countries recognized by the United Nations, there were 238 relevant societies found, from those 175 confirmed that they do not have clear guidelines. Only 32 associations/societies (all in either Europe and North America) recommend guidelines for their dentists (N = 12 guidelines) about the dental management of HNC patients and show their position regarding the use of dentures for HNC patients after receiving treatment with radiotherapy.ConclusionsThere are very few guidelines and those that do exist differ, lack detail, and rarely go beyond routine advice. Accordingly, clear, detailed, and evidence-based guidelines are required to inform the management of patients with missing teeth following radiotherapy for HNC patients.