Tooth Type Research Articles

Digital workflow to assess gingival recession coverage independently of the cemento-enamel Junction: a prospective clinical study using the modified coronally advanced tunnel technique with porcine dermal matrix

ObjectivesThe limited number of studies using digital workflows to measure soft tissue changes depend on the cemento-enamel junction (CEJ), which has been reported to be unreliable. Our primary objective was to apply an advanced digital assessment method, measuring independent from the CEJ to evaluate the modified coronally advanced tunnel technique (MCAT) with a porcine dermal matrix (PDM) for gingival recession coverage.Materials and methodsPatients with type RT1 and RT2 gingival recessions were treated with the MCAT and a PDM. Plaster casts (preoperative and 6 months postoperative) were digitalized. Subsequent stereolithography (STL)-files were imported and superimposed in the open-source software GOM Inspect for computer-based analysis. Recession depth, mean root and complete root coverage (mRC and cRC), mean recession reduction (mRR) and gingival thickness were evaluated. Statistical analysis was performed using mixed linear models.ResultsA total of 82 teeth (19 patients) were included in the study. Healing was uneventful in all patients. The mean preoperative recession depth was 1.34 ± 0.92 mm. mRC was 65.06 ± 48.26%, cRC was 25.61%, mRR was 0.87 ± 0.83 mm, and gingival thickness gain was 0.33 ± 0.30 mm, with comparable results for RT1 and RT2. Neither tooth type nor type of jaw had any effect on the amount of root coverage.ConclusionsThe digital evaluation workflow employed offers an approach to evaluate gingival recession coverage outcomes independent of the CEJ. The PDM used in combination with the MCAT shows promising results for root coverage.

Outcomes and prognostic factors of endodontically treated teeth filled with calcium silicate- or epoxy resin-based root canal sealers: A retrospective cohort study.

The objectives of this study were to compare the clinical outcomes of root canal treatment between calcium silicate-based sealer using the cold hydraulic condensation technique and epoxy resin-based sealer using warm vertical compaction and to identify the prognostic factors affecting the outcomes of both obturation techniques. Dental records and radiographs of the teeth that received root canal treatment with calcium silicate-based sealer using the cold hydraulic condensation technique or epoxy resin-based sealer using warm vertical compaction during 2015-2021 were selected using inclusion and exclusion criteria. The cases were matched between the two groups based on four factors: primary root canal treatment or retreatment, tooth type, periapical lesion and its size and extension of root canal filling. The success rates of root canal treatment between two sealers/obturation techniques were analysed. The incidence and resorption of extruded sealer were evaluated using the McNemar's test. Generalized estimated equations were used to evaluate any prognostic factors. The median recall period of this study was 15 months. A total of 234 teeth, comprising 117 cases in each sealer/obturation group, were included. No significant difference was found in the success rates between the calcium silicate-based sealer using the cold hydraulic condensation technique group (91.5%) and the epoxy resin-based sealer using the warm vertical compaction group (94.9%). The incidence of sealer extrusion for the calcium silicate-based sealer (27.6%) did not significantly differ from that of the epoxy resin-based sealer (36.2%), with both sealers typically demonstrating no resorption at recalls. No prognostic factors related to the success rate of either technique were detected. The study findings suggest no difference in the success rate between calcium silicate-based sealer and epoxy resin-based sealer. The study did not identify any prognostic factors that significantly influenced the outcomes of the endodontic treatments.

Tooth loss during long-term periodontal therapy in specialized practices – a retrospective cohort study from a periodontal practice-based research network (Perio-PBRN)

ObjectivesTo investigate tooth-specific, clinical tooth-, and patient-related factors associated with tooth loss (TL) in patients with mild to severe periodontitis treated in a periodontal practice-based research network (Perio-PBRN) over at least 5 years.Materials and methodsThe Perio-PBRN consists of five German periodontal practices where clinical data were collected regarding patient age, tooth type, bleeding on probing (BOP), pocket probing depth (PPD), furcation involvement (FI), number of attended appointments, and other variables of interest. The data were evaluated regarding factors influencing TL.ResultsData from 687 patients (aged 54.5 ± 11.1 years) with mild (N = 23, 3.35%), moderate (N = 247, 35.95%) or severe (N = 417, 60.70%) periodontitis and 15,931 teeth over a mean observation period of 6.83 ± 1.40 years per patient were gathered via the Perio-PBRN. In this period, a total of 657 teeth were lost (4.12%, overall TL: 0.14 ± 0.22 teeth/patient/y). The risk of TL was significantly increased for teeth with persistent PPD ≥ 6 mm (hazard ratio: 6.81 [95% confidence interval: 5.07–9.15] in comparison to PPD < 4 mm. Additionally, BOP (3.90 [2.46–6.19]), furcation involvement, jaw, age and tooth type showed a significant influence on TL, while number of visits were not significantly associated with TL.ConclusionsPeriodontal care of patients with moderate to severe disease in specialized practices was associated with a low rate of TL. Known tooth-related prognostic factors were confirmed. However, the results must be interpreted cautiously without knowledge of risk factors such as smoking and diabetes.Clinical relevancePBRNs can help gather large amounts of periodontal practice-level data.Trial registrationThe study was registered in the German Clinical Trials Register (DRKS 00011448).

Effectiveness of nonsurgical re-instrumentation: Tooth-related factors.

To investigate tooth-related factors that influence pocket closure (PC) and the reduction of pocket probing depths (PPD) after nonsurgical re-instrumentation (NSRI) as part of step 3 therapy. A total of 480 patients (10,807 teeth) presenting with residual pockets 6.33±3.79 months after steps 1 and 2 of periodontal therapy were included and retrospectively analyzed before and 5.93±4.31 months after NSRI. Reduction of PPD and PC rates following NSRI were associated with tooth-related factors, namely tooth type, arch, number of roots, furcation involvement (FI), pulp vitality, mobility, type of restoration, presence of plaque, and bleeding on probing (BOP), using mixed-effects regression models. NSRI reduced periodontal pockets persisting after initial cause-related therapy by (mean±SD) 1.32±1.79mm in PPD, and PC rate was 40%. Moderate pockets (4-5mm) responded better to NSRI than deep pockets (≥6mm) in terms of PC (51% vs. 16%). Both PPD reduction and PC rates of deep residual pockets were significantly influenced by tooth type, arch, number of roots, and presence of BOP. Tooth type, arch, number of roots, and presence of BOP at re-evaluation (before NSRI) had a significant and clinically relevant influence on NSRI as part of step 3 therapy. Considering these factors, particularly for deep residual pockets, may allow more tailored re-intervention. The present study aimed to investigate the influence of tooth-related factors on the outcome of repeated nonsurgical therapy of periodontitis. Therefore, 480 patients (10,807 teeth) presenting with clinical symptoms of persistent periodontitis after initial therapy were administered repeated nonsurgical therapy and retrospectively analyzed. Therapy outcomes were associated with tooth-related factors, namely tooth type, tooth location (maxilla/mandible), number of roots, involvement of the root furcation area in multi-rooted teeth, pulp vitality, mobility, restoration, presence of plaque and bleeding upon periodontal probing, using mixed-effects models. The results revealed that repeated nonsurgical therapy was effective in reducing inflammation and clinical signs of disease, with moderate residual periodontal defects responding better than deep defects. Healing of deep defects after repeated nonsurgical therapy; however, was significantly influenced by the factors: tooth type, location, number of roots, and bleeding on probing. Considering these factors, particularly in deep residual defects which are commonly suggested to be treated surgically, may allow less invasiveness and thus a more tailored re-intervention.

PROBLEMS OF CHOOSING A METHOD OF DENTAL TREATMENT OF TEETH AFTER ENDODONTIC INTERVENTION

The optimal way to restore the anatomical structure of teeth after endodontic intervention is a controversial topic. Teeth after endodontic intervention have different properties compared to intact living teeth. Changes in these properties are associated with volumetric loss of hard tissues, caries, final preparation of the cavity taking into account access to endodontic treatment. Choosing the optimal method of dental treatment of teeth requires compliance with many factors, such as: prevention of infection penetration into root canals, restoration of tooth contacts, restoration of chewing functions, protection against further carious and non-carious destruction, restoration of tooth aesthetics. Dentists are now more than ever aware of the interdependence of the endodontic and restorative aspects of dental treatment and how much this will affect achieving the best long-term outcome. Controversies of the clinical relevance of endodontic and restorative treatment choice issues are mostly unanswered based on clinical data and scientific evidence. The modern approach to tooth restoration after endodontic intervention is an important topic. To improve clinical outcomes, it is important to determine the effectiveness of treatment, the importance of preserving tooth structure, the choice of treatment method with restorative materials, and the integration of digital dentistry to improve diagnosis and treatment principles. Research rationale. The purpose of this study is to find and use literature data on the effectiveness of modern methods of dental treatment after endodontic intervention in Ukraine. Materials and methods. Scientific data from a review and systematic analysis of the literature were used. Materials were searched using the Google Scholar, PubMed, Google Scholar databases and open sources of the World Health Organization, the Ministry of Health of Ukraine and other government web portals of Ukraine. Results, Discussion. After conducting a literature analysis to compare the effectiveness of using cast metal inserts and fiberglass posts, we can come to the conclusions that retrospective studies on the relationship between successful restorations and such factors as the type of tooth, the volume of residual hard tissues, the number of occlusal contacts, the type of the final restoration and the position of the tooth in the dental arch are the main criteria for choosing a treatment method. A controversial choice is that metal abutments are associated with a higher risk of root fracture, their manufacture requires laboratory techniques, while the use of fiberglass posts is associated with a higher risk of decementation, and overloading of fiberglass posts leads to their fractures. Conclusions. Decision-making and the choice of methods of dental treatment after endodontic intervention remain difficult. However, the interdependence of endodontic treatment and restoration of the crown part of the tooth is clearly established. Physicians must consider both aspects of treatment equally to ensure the best possible outcomes for their patients. The use of digital scanning enables an accurate volumetric assessment of the residual hard tissues of the tooth, which can be used to provide tangible qualitative results of the analysis and decision-making with the choice of treatment method. The choice of treatment method is not defined in a single protocol and requires further careful study with new experimental developments, based on the latest technologies of world leaders in dentistry.

Does achieving apical patency increase postoperative pain during endodontics?

PubMed, Scopus, Embase, Web of Science, Cochrane Library, and gray literature up to May 2023. Twelve studies were included for meta-analysis. Two authors screened databases to identify suitable studies, with a third investigator resolving disagreements. Inclusion criteria were randomized controlled trials (RCTs) involving individuals without systemic diseases, who underwent root canal treatment in a permanent tooth with or without apical patency. Outcomes included pain, number of patients with pain and analgesic use. Exclusion criteria included patients who had undergone tooth extraction, incomplete data reports and studies which were not RCTs. There were no limits on publication language. A search of PubMed, Scopus, Embase, Web of Science, Cochrane Library, and gray literature from Google Scholar, ProQuest, OpenAire, and BASE identified 92 articles until May 2023. After removing 42 duplicates, 50 article full texts were assessed. Ultimately, 12 studies were included, seven of which were new relative to previous systematic reviews. Data were analysed using RevMan 5.4 software. Dichotomous categorical data were analysed through the Cochran-Mantel-Haenszel test, with the inverse variance method used for continuous data. Following assessment of heterogeneity with the χ2 test, fixed- or random- effects modeling was used. Pain scores were reported within one week by ten studies, but three were excluded from meta-analysis due to methodological issues. Studies involving participants aged 14-65 years, with pulp necrosis, apical periodontitis, or pulpitis, were included for analysis. Irrigation solutions varied from saline to sodium hypochlorite (2.25-5.25%), EDTA, citric acid, or chlorhexidine. Types of teeth treated included molars and anterior teeth. All studies used a 10# K-file for apical patency and various hand and nickel-titanium instruments for canal preparation. Generally, there was slightly reduced post-operative pain reported through the maintenance of patency. This was evident in the initial post-operative period of 24 h (OR = 1.69, P = 0.002), 1-day (MD = -1.69, P = 0.03) and 2-days (MD = -0.85, P = 0.04), but became non-significant over the remainder of the 7-day monitoring period. There was no significant difference in analgesic use between groups (OR = 0.82, P = 0.42). Studies were classified into three groups based on quality: four high quality with low risk of bias; three moderate quality with some concerns; and five low quality with high risk of bias. Evidence quality varied; pain scores on days 1 and 2 were of low quality, with very low quality for 12 h and days 3-6. High heterogeneity and imprecision were noted, especially in pain measurements and analgesic use. The meta-analysis indicates that during the initial post-operative period, apical patency significantly reduces postoperative pain. However, the findings should be interpreted cautiously due to high heterogeneity and variable evidence quality. Given that apical patency is seen as desirable for achieving the biological aims of endodontic treatment, the fact that it also appears to reduce post-operative pain helps to align patient reported outcome measures with traditional measures indicating success.

Survival analysis of primary molars following pulpectomy performed under dental general anesthesia: a five-year retrospective study

BackgroundCurrently, the indications for pulpectomy of primary molars performed under dental general anesthesia vary across countries. Therefore, we retrospectively investigated the five-year survival rate of primary molars following pulpectomy performed under dental general anesthesia and the impact of this treatment on permanent successors, assessed the risk factors related to overall survival and clarified the indications for pulpectomy.MethodsThe medical records of children receiving pulpectomy of primary molars under dental general anesthesia from August 1, 2013, to November 30, 2023, were reviewed. Potential risk factors, including gender, age, general health, tooth type, tooth location, endodontic diagnosis and quality of root filling, were assessed via univariate and multivariate Cox proportional hazards regression models, and the survival rate was examined via the Kaplan‒Meier technique. Moreover, the rate of resorption of the root canal filling materials, degree of resorption of the overfilled/over-extended root canal filling materials and development of permanent successors were assessed by clinical and radiographic examination.ResultsThe study included 320 teeth from 161 children (86 boys and 75 girls). The overall five-year survival rate was 38.2%, and the mean overall survival time was 54.2 months. Endodontic diagnosis was considered a significant risk factor (P < 0.05). In the first, second and third years, 57.4%, 81.8%, and 94.8%, respectively, of obturation materials in the root canals were resorbed at a faster rate than the roots. There was an altered eruption direction in 7 permanent teeth, and 4 permanent teeth were diagnosed with enamel hypoplasia.ConclusionsIn this study, the 60-month survival rate of primary molars treated by pulpectomy under dental general anesthesia was 38.32%. Operators should have an accurate assessment of the status of the pulp, have a strict grasp of the preoperative indications and select the appropriate treatment method according to the guidelines. Individual cases suggest overfilling, overextension and periapical periodontitis in primary molars have an impact on enamel hypoplasia and altered eruption direction in permanent teeth.

Prevalence of Dentine Hypersensitivity in Vital Abutment Teeth being prepared for Fixed Partial Dentures or Crowns

Objective: To determine the prevalence of dentine hypersensitivity during the preparation of vital abutment teeth for Fixed Partial Dentures or Crowns and its association with patient’s gender, age, and location of tooth. Study Design &amp; Setting: This is a descriptive cross-sectional study of patients with 150 abutments of either crown or fixed partial dentures, carried out in the department of Prosthodontics at Armed Forces Institute of Dentistry (AFID) Rawalpindi from June to December 2021. Methodology: The Dentine Hypersensitivity was recorded on a VAS (Visual Analogue Scale) of 0-10 after the patient reported pain during exposure to thermal stimulus i.e. cold water from a 5cc syringe at 1cm distance during or just after the tooth preparation. Results: In this study, the prevalence of Dentine Hypersensitivity was 13.3% with a mean dentine hypersensitivity score (VAS) for cold water test (Mean ± SD) of 0.61±1.756. Independent samples t-tests were used to determine the difference in hypersensitivity between genders, two age groups, and type of tooth (anterior/ posterior). It showed significant results with p-values of 0.002, 0.002, and 0.003 respectively. Conclusion: Within the limitations of this study, it was highlighted that the preparation of vital teeth for conventional porcelain fused to metal (PFM) crown or fixed dental prosthesis results in dentine hypersensitivity in a considerable number of cases, with a higher incidence in women, younger patients, and vital anterior abutments.

Effect of orthodontic space closure on dental pulp sensitivity. Prospective clinical trial.

Orthodontic tooth movement (OTM) is a biological process that can influence the function of the pulp, including its innervation. The excitability of the nerve fibres of the pulp may be altered by forces exerted on the nerve fibres or by reduced blood flow to the pulp. The aim of this clinical study was to evaluate the sensitivity of the dental pulp during levelling and during the phase of space closure, to assess the role of certain controlled risk factors. Twenty-two adolescent participants requiring orthodontic space closure in transcanine sector were enrolled in a prospective clinical study. Patients were observed before OTM, after levelling and 1 month during active space closure. The sensitivity threshold of the pulp was measured using the electric pulp test (EPT). Dental models were obtained using an intraoral scanner, allowing measurement of interdental distances and calculation of OTM speed. The teeth were categorized according to position and tooth type. The EPT values increased significantly during orthodontic treatment (one-way RM-ANOVA, P = .014). There was a significant difference in EPT values between the tooth categories. Teeth with a single root adjacent to the residual space had the highest EPT thresholds (two-way RM-ANOVA, P < .001; Holm-Sidak, P < .05). OTM reduced pulpal sensitivity. Pulpal sensitivity during active space closure was similar to sensitivity during the levelling phase. The pulpal sensitivity of molars was less affected by OTM than that of single-rooted teeth, while teeth closer to the gap had a significantly higher pulpal sensitivity threshold during active OTM.

Ighmbp2 mutations and disease pathology: Defining differences that differentiate SMARD1 and CMT2S

Mutations in the Immunoglobulin mu DNA binding protein 2 (IGHMBP2) gene result in two distinct diseases, SMA with Respiratory Distress Type I (SMARD1) and Charcot Marie Tooth Type 2S (CMT2S). To understand the phenotypic and molecular differences between SMARD1 and CMT2S, and the role of IGHMBP2 in disease development, we generated mouse models based on six IGHMBP2 patient mutations. Previously, we reported the development and characterization of Ighmbp2D564N/D564N mice and in this manuscript, we examine two mutations: D565N (D564N in mice) and H924Y (H922Y in mice) in the Ighmbp2H922Y/H922Y and Ighmbp2D564N/H922Y contexts. We found significant differences between these mouse models, providing critical insight into the role of IGHMBP2 in the pathogenesis of SMARD1 and CMT2S. Importantly, these studies also demonstrate how disease pathogenesis is significantly altered in the context of Ighmbp2 D564N and H922Y homozygous recessive and compound heterozygous mutations. Notably, there were short-lived and long-lived lifespan cohorts within Ighmbp2D564N/H922Y mice with early (P12/P16) respiratory pathology serving as a key predictor of lifespan. Despite differences in lifespan, motor function deficits initiated early and progressively worsened in all Ighmbp2D564N/H922Y mice. There was decreased limb skeletal muscle fiber area and increased neuromuscular junction (NMJ) denervation in Ighmbp2D564N/H922Y mice. Consistent with CMT2S, Ighmbp2H922Y/H922Y mice did not have altered lifespans nor respiratory pathology. Interestingly, Ighmbp2H922Y/H922Y limb muscle fibers demonstrated an increase in muscle fiber area followed by a reduction while changes in NMJ innervation were minimal even at P180. This is the first study that demonstrates differences associated with IGHMBP2 function within respiration with those within limb motor function. Significant to our understanding of IGHMBP2 function, we demonstrate that there is a direct correlation between disease pathogenesis associated with these IGHMBP2 patient mutations and IGHMBP2 biochemical activity. Importantly, these studies reveal the dynamic differences that are presented when either a single mutant protein is present (IGHMBP2-D564N or IGHMBP2-H922Y) or two mutant proteins are present (IGHMBP2-D564N and IGHMBP2-H922Y) within cells.

Assessment of Severity and Pattern of Early Childhood Caries Using ICDAS II Criteria: A Descriptive Cross-sectional Study

Introduction: Early childhood caries is highly prevalent worldwide. The International Caries Detection and Assessment System incorporates both the non-cavitated and cavitated carious lesions with acceptable reliability. The objective of the present study was to assess the severity and pattern of early childhood caries among children visiting outpatient department of a dental college in Nepal. The study also aimed to compare the severity and pattern based on individual tooth type. Methods: A cross-sectional study was conducted among children of age group 24-71 months in primary dentition stage. The International Caries Detection and Assessment System II criteria was used to detect dental caries, and its severity and pattern. The ethical approval was taken from the institutional ethical committee (IRC Ref. No.: 1, 36, 2079/2080 IRC PDCH 2022 21).Results: The dental cries in children of age group 48-60 months was 1338 (33.46%) and dentinal caries (Code 5) was observed in 112 (8.37%). Multi-surface caries was 644 (16.15%), and occlusal surface caries was 481 (12.06%). Among the study population, 227 (5.69%) of the teeth assessed were associated with restoration and sealants. Enamel caries among the maxillary second molars (55/65) (Code 3) was in 94 (23.5%), and the dentinal caries (Code 5) in maxillary central incisors (51/61)was in 90 (22.78%). Conclusions: Majority of the children enrolled in the study had multiple cavitated and non-cavitated carious teeth involving different surfaces. Severity and pattern of caries also varied among individual tooth type.

A retrospective study on the outcome of pulpotomy with iRoot BP plus in primary molars and its relationship with hemostasis time

BackgroundPulpotomy is a crucial method to preserve primary teeth until natural exfoliation. This study aimed to evaluate the clinical and radiographic outcomes of pulpotomy with iRoot BP Plus in primary molars and to explore the association between hemostasis time and these outcomes.MethodsPrimary molars that underwent iRoot BP Plus pulpotomy and were followed for at least 12 months were selected for this study. Clinical and radiographic data were collected, and the success rate was analyzed in relation to factors such as hemostasis time, tooth type, and arch type. The tests of significance used were the chi-square test, Fisher’s exact test, or Kruskal-Wallis test. Statistical significance was set at P < 0.05.ResultsA total of 183 teeth in 106 patients were included in the analysis. The follow-up period fell into a range of 1–3 years, with a mean of 1.6 years. The clinical and radiographic success rates were 96.7% and 92.9%, respectively. The earliest time to observe the radiographic failures was half a year after the treatment, and the latest time was two years after the treatment. Among all the teeth, 130 were recorded with hemostasis time before the application of iRoot BP Plus. Compared to teeth with a hemostasis time of 5 min or less, teeth with a hemostasis time exceeding 5 min showed no significant differences in clinical and radiographic success (P = 1.000 and 0.879). Additionally, neither arch nor teeth type showed a relationship with the pulpotomy success rate (P > 0.05).ConclusionsPulpotomy using iRoot BP Plus in primary molars achieved favorable results. The hemostasis time may not significantly impact the outcomes of pulpotomy using iRoot BP Plus in primary molars.

Integrative approach for supernumerary teeth: a single-center retrospective analysis.

This study aimed to provide a comprehensive case analysis from a single center, with the objective of clarifying the optimal timing and recommendations for a preferred treatment strategy customized to the specific presentation of each type of supernumerary tooth identified in the research. A retrospective study was conducted on patients who presented with a supernumerary tooth and were treated interdisciplinarily at the clinic. In total, 55 patients with 81 supernumerary teeth of the permanent dentition were analyzed, 30 males and 25 females. The dentition status of the patients was as follows: 31 patients with mixed dentition, no patients with primary dentition, and 24 patients with permanent dentition. The diagnosis of supernumerary tooth was primarily made by general or pediatric dental practitioners and/or orthodontists. Patients were then referred to maxillofacial surgeons for treatment decision. The timing of treatment was mainly determined by the oral surgeon, based on the recommendations of the other specialists involved. Cases involving maleruption or malalignment of permanent teeth required both surgical and orthodontic treatment. Patients over 9 years old were treated either under local anesthesia or sedation, whereas those under 9 years old were treated under deep sedation or general anesthesia. A comprehensive investigation of cases involved the utilization of CBCT at the supernumerary tooth site to facilitate treatment planning. There was a significant correlation between younger age and the preference for treatment under sedation or general anesthesia (P &#61; .01, t test). Similarly, a strong association was found between younger age and the need for additional orthodontic treatment (P &#61; .016, t test). Cases of surgical removal of a supernumerary tooth at a young age typically did not require orthodontic traction of the permanent tooth, in contrast to cases of late surgical intervention (patients over 11 years old), which often did necessitate such traction. There was a strong tendency for treating supernumerary teeth in the maxilla. The proximity of supernumerary teeth to vital anatomical landmarks significantly influenced treatment decisions. Patients with supernumerary teeth near the mental foramen or the inferior dental canal in the premolar area were exclusively placed under follow-up care (P &#61; .002, Pearson chi-square test). However, in the maxilla, the proximity of supernumerary teeth to vital structures such as the floor of the nose and the incisive nerve did not affect the treatment approach, and those supernumerary teeth were mostly removed. A team approach for managing supernumerary teeth is recommended. The timing of treatment should carefully consider the advantages and disadvantages of early versus late intervention. Early surgical treatment in cases where eruption is disturbed might result in spontaneous eruption, eliminating the need for orthodontic traction of the permanent teeth.

Evaluation of magnetic orientation in dual-stator linear permanent magnet vernier machine for wave energy conversion

The Permanent Magnet Vernier Machine (PMVM) is favored for wave energy conversion due to its high torque production at low speeds and straightforward design. This study introduces the innovative Dual Stator Linear Permanent Magnet Vernier Machine (DSLPMVM) with concentrated winding. In this design, permanent magnets (PMs) are strategically placed on both the stator and a segmented translator, enhancing system reliability. The stator utilizes a simple PM layout, while the translator features a Halbach array. This research advances the DSLPMVM’s performance through the optimal placement and orientation of magnets, alongside a meticulous selection of tooth types. The paper rigorously evaluated all possible magnetic orientations and eight distinct stator tooth models. Detailed comparisons of flux linkage, back electromotive force (back-EMF), inductance, efficiency, power factor (PF), and force were conducted to identify the most effective designs.

Factors Related to Bracket Bond Failure during Orthodontic Treatment: A Single-Centre Single-Operator Study.

This study aimed to investigate the influence of various patient-specific and bracket location-specific factors on bracket survival rates during comprehensive fixed appliance orthodontic treatment. A total of 197 patients (116 females, 81 males; mean age 16.3 years) having completed orthodontic treatment were included in this retrospective cohort study. Patients were treated using stainless steel non-self-ligating brackets, and the treatment duration was 23.7 months on average. The primary outcome was bracket bond failure. Potential predictors for bracket bond failure recorded included age, sex, oral hygiene, treatment duration, and several pre-treatment cephalometric characteristics such as overjet, overbite, and sagittal and vertical skeletal relationships. Factors associated with bracket failure were analysed with Cox regression, and proportional hazard assumptions were assessed using Kaplan-Meier tests. The overall failure rate was 4.4%. Bracket bond failure rates varied among tooth types and seemed to occur more on posterior teeth and on the right side of the arch. Bracket failure was more common in male patients and those with poor oral hygiene. Concerning dentofacial characteristics, bracket failure of anterior teeth was more common in those with an increased overjet and overbite.

Identifying marginal adaptation discrepancies of lithium disilicate crowns using seven different vertical X‐ray angulations

AbstractPurposeTo study the effect of different vertical angulations on the ability to radiographically assess vertical marginal discrepancies of lithium disilicate crowns.Materials and MethodsTwenty‐one lithium disilicate crowns were fabricated for three different prepared natural teeth: incisor, canine, and premolar. Vertical marginal discrepancies ranging from 0 to 300 µm were intentionally created. The seated crowns were radiographed using seven different vertical angulations, totaling 147 images. Thirty experienced evaluators scored each image for marginal discrepancy, and values were statistically analyzed.ResultsSignificant differences in the ability to accurately assess marginal discrepancies from radiographs were observed for the study factors of angulation, tooth type, and degree of marginal discrepancy (p &lt; 0.001).ConclusionsThe radiographic interpretation of the marginal discrepancies of lithium disilicate crowns is significantly affected by the dimension of the marginal discrepancy. Specifically on premolar crowns, it is significantly affected by different vertical angulations of the X‐ray beam. When evaluating marginal discrepancy on lithium disilicate crowns radiographically, vertical beam angulation within ±10° to the cemento‐enamel junctionCEJ plane is recommended.

Clinical internal and marginal fit of metal‐ceramic fixed dental prostheses fabricated with selective laser melting and 3D‐printed pattern casting using cobalt‐chromium metal alloy

AbstractPurposeTo evaluate the fit of metal–ceramic three‐unit fixed dental prostheses (FDPs) fabricated using selective laser melting (SLM) and 3D‐printed casting pattern (CP) and to compare the effect of tooth type and ceramic veneering on marginal and internal gaps.Materials and MethodsPatients requiring posterior three‐unit FDPs were selected. For each subject, two FDPs were fabricated using SLM and CP. Silicon replica was used to measure the internal and marginal fit of frameworks before and after ceramic veneering. For each replica, 36 measurements were performed using a stereomicroscope: 4 marginal and 32 internal (4 deep chamfers, 12 axial, 4 axio‐occlusal, and 12 occlusal). Statistical analysis was performed using two‐way ANOVA and paired t‐test.ResultsA total of 44 metal–ceramic FDPs were fabricated in 22 patients. The results showed that the fabrication method had no significant effect on the marginal, deep chamfer, or occlusal gaps. However, the method significantly affected the axial, axio‐occlusal, and total internal fit, and the SLM had larger gaps than the CP. For the effect of ceramic veneering, measurements were significantly higher in the CP group at all gaps, except for the premolar axial and molar occlusal gaps. The SLM fit was less affected by ceramic veneering. Only premolar gaps significantly increased at the marginal, deep chamfer, and axial and axio‐occlusal positions.ConclusionMetal–ceramic FDPs fabricated using SLM and CP techniques provided a similar marginal fit. Premolars had smaller discrepancies compared to molars. The ceramic veneering process increased the gap of the prostheses, with SLM being less affected by ceramic veneering.

Dentitions of Long-Term Care Residents: Tooth Types, Roles in Occlusion and Association with Dementia.

Background/Objectives: Many older adults living in long-term care (LTC) environments have varying numbers of retained natural teeth. The objective of this study was to assess the disease findings based on tooth type and estimate the role of tooth types in occlusion. Methods: We conducted clinical oral examinations of 276 LTC residents. The disease findings were analyzed for each tooth type and to determine their associations with dementia. Results: In total, 67.8% of the participants had molar teeth. Premolars/canines were often present as residual roots and had caries. Deepened periodontal pockets and higher plaque index (PI) values for molars had odds ratios of 2.5 (95% confidence interval [CI] of 1.59-3.91) and 1.61 (95% CI of 1.29-2.02), respectively. Participants with dementia were more likely to have incisors and premolars/canines in the form of root remnants and higher PI scores for all tooth types (p ≤ 0.01), as well as more deepened periodontal pockets in all teeth (p = 0.029), than those without dementia. The median number of remaining molars per participant was 3 out of a maximum of 12 (95% CI 3.4-4.0); thus, they often lacked occlusal contact. Conclusions: The LTC residents' molars were more prone to periodontal problems, whereas their premolars/canines often had caries or were present in the form of root remnants, especially in the participants with dementia. People's teeth should be treated in an easy-to-maintain way before they move into LTC to enable daily oral hygiene measures and maintain oral health.

Assessment of Risk Factors and Prognostic Predictors for Endo-Perio Lesions in Indian Cohorts: An Observational Study.

Endodontic and periodontal tissues exhibit a significant interrelationship, whereby pathologies affecting one tissue can precipitate the involvement of the other. The primary objective of this study was to assess the risk factors associated with endo-perio lesions (EPLs). The secondary objective was to assess the prognostic predictors for such lesions and the prevalence rate of EPLs involving both pulpal and periodontal tissues in Indian cohorts. A prospective observational study was conducted on 2170 teeth with EPLs in Indian adults aged > 18 years. A detailed history of smoking, tobacco chewing, and the development of EPLs was obtained from all patients. Detailed periodontal and endodontic examinations were conducted by two calibrated examiners. Intraoral periapical radiographs (IOPAs) were obtained to diagnose EPLs. The chi-square test of association was used to analyze the association between independent and dependent variables, and the strength of association was presented by Pearsoncontingency coefficient (r). Logistic regression analysis was performed to identify reliable factors for diagnosing EPLs. A statistical significance threshold of 0.05 was established. The prevalence of EPLs involving pulpal and periodontal tissues was 29.49%. Type 1 lesions (EPLs involving only pulpal tissue) were most commonly seen at 41-45 years of age, type 2 lesions (EPLs involving primary pulpal and secondary periodontal tissue), and type 3 lesions (EPLs involving only periodontal tissue) at 26-30 years of age, and type 4 lesions (EPLs involving primary periodontal and secondary pulpal tissue) at 31-35 years of age. The pulp was found to be non-vital in all cases of type 3 lesions, and faulty restoration or improper root canal treatment (RCT) was the main risk factor for such lesions. Occupational trauma was found to be the most common risk factor for type 3 and type 4 lesions. Smoking, age, tooth type, occlusal trauma, faulty restorations and RCT, presence of caries, periapical pathology, periodontitis, bone loss, and pulp vitality were significantly associated with EPLs. Pulp vitality and bone loss were two prognostic predictors of EPLs.

A Comparative Study to Explore the Variability of Heavy Metal Concentration in the Teeth of Residents of Non-gated Versus Gated Societies.

Human populations face increasing exposure to heavy metals, which pose significant health risks. Dental tissues, such as dentin and enamel, provide a reliable biomarker for assessing long-term heavy metal exposure due to their stable nature. This study aims to explore the variability of heavy metal concentrations in the teeth dentine of residents living in gated versus non-gated societies near the Yamuna Riveraround the Jamia Millia Islamia, New Delhi, India. Sixty-nine participants were enrolled, 27 from gated societies and 42 from non-gated societies. Participants underwent elective dental extraction,following whichheavy metal concentrations were measured in extracted tooth dentine using atomic absorption spectrophotometry. Demographic data including age, gender, tooth types, and drinking water sources were recorded. Statistical analysis included Mann-Whitney's test, Spearman correlation heatmap, and principal component analysis (PCA). Residents of non-gated societies exhibited significantly (p< 0.005) higher mean concentrations of heavy metals compared to gated societies except for cadmium (p = 0.495). Subgroup analysis based on drinking water sources revealed significant (p<0.001) variations in heavy metal concentrations, suggesting the influence of water quality on environmental exposure. PCA provided insights into underlying trends and correlations among heavy metal variables. This study provides valuable insights into heavy metal contamination among residents living near the Yamuna River, highlighting disparities in exposure based on residential environment and drinking water sources. Participants from non-gated societies exhibited higher mean concentrations of heavy metals compared to those from gated societies, emphasizing the influence of socio-economic factors, urban infrastructure and environmental management practices on heavy metal accumulation. The study's findings underscore the need for targeted interventions to address heavy metal exposure across diverse population groups, improve water quality standards, and enhance access to safe drinking water.