Tooth Surface Research Articles

The Application of Resin Infiltration Combined with Nano-Hydroxyapatite in the Treatment of Post-Orthodontic White Spot Lesions

This study aims to investigate whether the combination of resin infiltration and nanohydroxyapatite (nHA) can provide a synergistic treatment for post-orthodontic white spot lesions (WSL), thus establishing an experimental basis for its treatment. For this study, a total of 60 bicuspid teeth that required extraction due to orthodontics were collected. Orthodontic models were established for each tooth sample, and demineralization staining was conducted using Coca-Cola. The dental samples were randomly divided into 4 groups: control group, nHA group, resin infiltration group, and resin infiltration+nHA group. The demineralized samples were remineralized with 10% nHA and Icon resin infiltration, respectively. The samples were subjected to color difference observation, microhardness test, energy-dispersive X-ray spectrum analysis, and surface roughness detection. The results showed that the tooth surface of the control group was rough and dull after demineralization. The area around the bracket exhibited a brown color, greatly contrasting with the color of the surrounding tooth enamel. After the remineralization treatment with nHA and resin infiltration, the color difference decreased significantly and the microhardness increased. A significant difference was observed between the nHA group and the resin infiltration group (P < 0.05). However, the combination of resin infiltration and nHA exhibited superior staining resistance and improved WSL microhardness value. Additionally, nHA was found to enhance the mass ratio and molar ratio of calcium to phosphorus in WSL samples, while also reducing the surface roughness Ra, demonstrating a greater effectiveness compared to resin infiltration. The use of nHA following resin infiltration led to a significant improvement in mineral deposition and a substantial reduction in surface roughness. In conclusion, both resin infiltration and nHA play a crucial role in promoting enamel remineralization, offering their respective advantages in reducing color difference, increasing microhardness and calcium and phosphorus content, and reducing surface roughness in WSL samples. Remarkably, the combined application of resin infiltration and nHA enables resin infiltration to improve the remineralization and anti-coloring ability in WSL, while preserving its aesthetic effects. This combination demonstrates a positive application outcome.

Comparative evaluation of the differential staining ability of carbol fuchsin, methylene blue, and turmeric GC-MI paste between enamel and adhesive composite remnant after orthodontic debonding using a spectrophotometer

Background: After debonding, the primary concern of the clinician is to ensure the complete removal of the orthodontic adhesive composite remnant and restore the tooth surface to as near its original state as possible. However, the color resemblance of composite adhesive and enamel can increase the risk of tooth damage during debonding. To delineate composite from enamel, using various hydrophobic stains can be helpful in clean debonding. Objective: The aim of the present research was to assess and compare the differential staining ability of three stains, i.e., carbol fuchsin, methylene blue, and turmeric GC-MI paste, using a spectrophotometer. Methodology: A total of 48 premolar samples were distributed among three groups, namely, Group A, Group B, and Group C. Each group of 16 samples was stained with carbol fuchsin, methylene blue, and turmeric GC-MI paste, respectively. The color value of enamel and composite was measured before and after staining by digital spectrophotometer using CIE L* a* b* scoring method. Results: The mean difference color value of composite and enamel before and after staining was found to be 38.473 ∆ E, 17.211 ∆ E, and 18.715 ∆ E and 1.647 ∆ E, 1.297 ∆ E, and 1.293 ∆ E in Groups A, B, and C, respectively. The mean color value of composite and enamel was compared before and after staining using a t-test for all three groups and was found to be statistically highly significant. Conclusion: Carbol fuchsin, methylene blue, and turmeric GC-MI paste have the potential to be used as composite disclosing agents. Turmeric GC-MI paste appears to be a better agent as it stains composite effectively without significant staining on enamel.

Locally-Delivered 1% Metformin Gel as an Adjunct to Scaling and Root Planning in the Treatment of Severe Chronic Periodontitis: A Randomized, Controlled Clinical Trial

Background: Periodontitis is a chronic inflammatory disease that affects the teeth’s supporting structures, leading to clinical attachment loss, pocket formation, and tooth loss if left untreated. Scaling and root planning (SRP) is the gold standard for removing bacterial biofilm and calculus from tooth surfaces. However, in most situations, including tooth fractures, there is a need for adjunctive therapies to complement and improve treatment outcomes. This study aimed to evaluate the efficacy of locally delivered metformin (MF) 1% gel as an adjunct to SRP in treating severe chronic periodontitis. Materials and Methods: A total of 36 volunteers were randomly assigned to two treatment groups, namely, SRP plus placebo gel and SRP plus 1% MF gel. Clinical parameters such as pocket probing depth (PD), clinical attachment level (CAL), and gingival recession (GR) were recorded at baseline, 2, and 4 months. The data were analyzed using independent T-tests, one-way, and repeated measures analysis of variance (ANOVA) using SPSS 24 software. Results: All groups exhibited improvements in periodontal parameters such as PD and CAL. While the mean reductions in PD and CAL were not statistically significant after 3 weeks of treatment between the two groups (P=0.193), the MF group demonstrated significantly greater improvements in PD, measuring 3.49 mm compared to 1.87 mm in the control group (P=0.007), as well as in CAL, which measured 2.98 mm versus 1.72 mm in the control group (P=0.014). Conclusion: The adjunctive use of locally delivered 1% MF gel could stimulate a significant reduction in PD and increases in CAL compared to the placebo gel, while there was no GR resulting from the local delivery of the drug. This suggests that the MF gel may offer benefits in the treatment of severe chronic periodontitis by enhancing periodontal healing without inducing GR.

Chatter and Surface Waviness Analysis in Oerlikon Face Hobbing of Spiral Bevel Gears

A vectorized analytical model for the cutting dynamics in the spiral bevel gear face hobbing process has been developed, which is based on machine tool kinematics and vibration vectorization. The structural modal parameters of the cutter head spindle system are obtained through experimental modal analysis with hammer impact testing. The analytical model is utilized to simulate the generation of simulated vibration acceleration signals during spiral bevel gear hobbing. A wavelet threshold denoising method is applied to process the simulated vibration signals of the spiral bevel gear face hobbing with added white noise. Signal processing methods, including short-time Fourier transform are employed for time-domain analysis, frequency-domain analysis, and time–frequency-domain analysis of measured signals and simulated signals, thereby extracting the corresponding statistical features. In addition to the results of the experimental modal analysis, the causes of chatter in spiral bevel gear hobbing are discussed in detail, revealing that the main factor is cutter head vibration in the Y direction of the Hunan ZDCY CNC EQUIPMENT YKA2260 machine tool used in this research. The error in the time-domain characteristic parameters between simulated signals and measured vibration acceleration signals is within 15%, with a difference of 3.5% in spectral peak values. The predicted tooth surface morphology from simulation matches the actual morphology on the workpiece, comprehensively validating the reliability of the cutting dynamics model for the spiral bevel gear face hobbing process. Another conclusion drawn from numerical simulation experiments is that the amount of tooth surface waviness of the spiral bevel gears is the ratio of tool chatter frequency to cutting fundamental frequency.

Tooth surface loss: causes, management, and prevention.

Tooth wear, also referred to as tooth surface loss, occurs due to causes other than caries. This involves the loss of hard tissues, namely enamel, dentin, and/or cementum. Types of tooth wear/tooth surface loss are abrasion, abfraction, attrition, and erosion. These multifactorial conditions can be caused by factors such as lifestyle, diet, or even habits, and may not be symptomatic. The focus of this article is to provide clinicians with detailed examples and explanations of the causes of tooth loss to aid in early diagnosis. Through early identification, the preventive measures outlined can be implemented to avoid excessive tooth wear. The provision of a treatment flowchart and general treatment recommendations aims to help clinicians determine when to restore these lesions and the most appropriate treatment measures for the four types of wear. The PubMed (MEDLINE) search engine was used to gather information on teeth restricted to a 5-year period (26 August 2018 to 25 July 2022). Only English-language studies and reviews with the best balance of sensitivity and specificity were considered. A Boolean search of the PubMed dataset was implemented to combine a range of keywords: ("tooth wear" OR tooth attrition OR tooth erosion OR tooth abrasion OR tooth abfraction). Additional articles were selected through Google Scholar. By this process, many articles and studies were obtained, and the 48 most relevant published studies were chosen and used in the current review. Tooth wear affects an increasing number of individuals and can have detrimental effects physically, mentally, and emotionally. It is important to stress early diagnosis and management of tooth wear through monitoring, prevention, and treatment where indicated.

A Photographic Approach Studying the Orientation of the occlusal plane of the Malaysian Population. A Proposal for an Orienting Device

The occlusal plane is crucial in prosthodontic reconstructive treatment as it affects the most important factors for the proper functioning of the artificial prostheses. The achievement of correct occlusal plane position offers maximum aesthetic, phonetic, mastication, and patient’s satisfaction. An incorrectly oriented occlusal plane interferes with denture stability and retention, in addition to more vital functions of the teeth and oral cavity. This study used a photographic approach to determine the occlusal plane inclination in relation to some anatomical references. 95 young volunteers of Mahsa University College, aged between 20 and 25 years, were selected for this study. The participants were selected according to specific inclusion criteria. A standardized digital profile and front images were taken for each participant using a digital camera that is fixed on a tripod with the fox bite plane placed on the occlusal surfaces of the maxillary teeth. The angle amplitude of the reference planes in relation to the occlusal plane was measured using a digital protractor on the screen display. The results revealed that the least mean angle difference was with the AT1, while higher variability was found using the Frankfort plane. In addition, there were no significant differences between the two genders or among the three ethnic groups. It is concluded that the photographic method can be used successfully to study the occlusal plane, and the lowest point of the tragus is the best posterior reference point to determine the ideal location of the occlusal plane.

FLUOROSIS PREVALENCE AT DIFFERENT REGIONS OF THE EARTH (LITERATURE REVIEW)

The aim of the study is to analyze the literature about the fluorosis prevalence and the factors which lead to dental and bone fluorosis. The search for articles published in 2016-2023 was conducted by the authors in Scopus and Web of Science scientific data bases using the keywords “fluorosis”, “dental fluorosis”. To classify the severity of dental fluorosis, the index of developmental defects of enamel (DDE), the index of tooth surface fluorosis (TSIF), and mostly Dean’s index Thylstrup & Fejerskov Index (TFI) are used. The risk factors for dental fluorosis include living in regions with high level of fluoride, drinking water with high level of fluoride or salt fluoridation, drinking bottled water, use of fluoride toothpastes among preschool children, early weaning, and use of infant formula for long time, and, as well as, a hot climate and high fluoride content in soil and food. The studies from India and China demonstrated that the average concentration of dental fluorosis and skeletal fluorosis at fluoride contained 6 mg/l. The prevalence of dental fluorosis in NorthernTanzania, where the fluorine content in daily drinking water is 3.6 mg/l, reaches 75,22%. In Ethiopia, where fluorine content is 5.09 mg/l, the prevalence of skeletal fluorosis ranges from 55.1% to 72.4%. In Kenya, the fluoride content in drinking water reaches 72 mg/l, so the prevalence of dental fluorosis is 80%. The prevalence of dental fluorosis is lower in South Western Saudi Arabia and Iran where fluoride level is lower. In Jordan, the prevalence of dental fluorosis reaches 39.9% due to the high fluoride content in miner rocks. Skeletal fluorosis is wide spread in some areas of Pakistan due to the contamination of ground water by industrial production. The prevalence of mild dental fluorosis is 39% in New castle where water is fluoridated, and 24% in non-fluoridated Manchester in England. Dean’s index and TFI index are mostly used to classify these variety of fluorosis. Various factors affect the appearance of dental and bone fluorosis worldwide, so the prevalence of fluorosis varies from 11,1 up to 100%.

Meshing stiffness characteristics of modified variable hyperbolic circular-arc-tooth-trace cylindrical gears

Abstract. Stiffness excitation is one of the important excitations for the variable hyperbolic circular-arc-tooth-trace (VH-CATT) cylindrical gear system. Accurate calculation of the gear meshing stiffness is of great significance to investigating dynamic characteristics of the VH-CATT cylindrical gear system. Firstly, based on the forming theory of the modified tooth surface, the modified tooth surface equation of the VH-CATT cylindrical gear was deduced, and the 3D reconstruction was realised. Next, the load tooth contact analysis (LTCA) model of the VH-CATT cylindrical gear was developed to calculate the meshing stiffness of the VH-CATT cylindrical gear, and it was verified by the finite-element calculation. Finally, the influence of the load and modification parameters on the VH-CATT cylindrical gear stiffness was investigated. Research shows that the stiffness calculation method of the VH-CATT cylindrical gear based on LTCA is accurate. The meshing stiffness of the VH-CATT cylindrical gear in the double-tooth meshing area is large, and the meshing stiffness of the VH-CATT cylindrical gear in the single-tooth meshing area is small. The stiffness of the VH-CATT cylindrical gear increases with an increase in the load and cutter inclination angle, the stiffness of the VH-CATT cylindrical gear only in the double-tooth meshing area decreases with an increase in the parabolic coefficient, and the stiffness of the VH-CATT cylindrical gear increases with a decrease in the blade parabolic vertex position value. The research results provide a basis for improving the bearing capacity of the VH-CATT cylindrical gear and optimising design.

Numerical Analysis of Tooth Contact and Wear Characteristics of Internal Cylindrical Gears with Curved Meshing Line

In order to improve the contact strength and reduce the sliding friction of the gear pair, an internal cylindrical gear pair with a curved meshing line is studied in this paper. Firstly, a curved meshing line is designed. The tooth profiles of the internal gear pair with the designed meshing line are calculated by using differential geometry and the gear meshing principle. Secondly, a wear model is established by combining the finite element method and the Archard wear formula. Then, a numerical simulation is conducted; the relative curvature, sliding coefficient, sliding distance, maximum contact pressure, transmission error, and wear depth are calculated. Ultimately, the variation law of tooth surface wear of new gear with and without installation errors is observed under different stress cycles. On this basis, the influence of tooth modification on tooth surface wear is further researched. Through the results, the advantages of the introduced novel internal cylindrical gears in wear resistance are further demonstrated. The study in this paper provides new research ideas and methods for gear wear research and gear design.

Effect of the Height of a 3D-Printed Model on the Force Transmission and Thickness of Thermoformed Orthodontic Aligners.

This research aims to investigate the influence of model height employed in the deep drawing of orthodontic aligner sheets on force transmission and aligner thickness. Forty aligner sheets (Zendura FLX) were thermoformed over four models of varying heights (15, 20, 25, and 30 mm). Normal contact force generated on the facial surface of the upper right central incisor (Tooth 11) was measured using pressure-sensitive films. Aligner thickness around Tooth 11 was measured at five points. A digital caliper and a micro-computed tomography (µ-CT) were employed for thickness measurements. The normal contact force exhibited an uneven distribution across the facial surface of Tooth 11. Model 15 displayed the highest force (88.9 ± 23.2 N), while Model 30 exhibited the lowest (45.7 ± 15.8 N). The force distribution was more favorable for bodily movement with Model 15. Thickness measurements revealed substantial thinning of the aligner after thermoforming. This thinning was most pronounced at the incisal edge (50% of the original thickness) and least at the gingivo-facial part (85%). Additionally, there was a progressive reduction in aligner thickness with increasing model height, which was most significant on the facial tooth surfaces. We conclude that the thermoplastic aligner sheets undergo substantial thinning during the thermoforming process, which becomes more pronounced as the height of the model increases. As a result, there is a decrease in both overall and localized force transmission, which could lead to increased tipping by the aligner and a diminished ability to achieve bodily movement.

A Comparative Evaluation of Removable Partial Denture Prostheses and Dental Caries Status among Diabetic and Nondiabetic Patients

Abstract Introduction Oral health is an integral part of general health. Systemic diseases such as diabetic condition and local factors have an impact on oral health of individuals. Dental caries is one of the most common oral health conditions affecting 60 to 90% of the population. Acrylic removable partial denture (RPD) is one of the most widely accepted means of tooth replacement. Its insertion in the mouth leads to altering the oral environment and increases plaque formation, particularly on tooth surface of those in contact with the acrylic partial denture facilitating the initiation of caries. Aim The aim of the study was to evaluate the effect of acrylic RPDs on caries prevalence in diabetic and nondiabetic patients. Methodology This comparative study was performed on 400 patients of age between 20 and 64 years visiting JSS Dental College and Hospital in Mysuru. Patients participating in this study were explained regarding the survey analysis and informed consent was taken. It was a questionnaire-based clinical study. Inclusion and exclusion criteria were considered for the selection of the study sample and categorize the patients into one of the following groups, with prostheses (Group A) and without prostheses (Group B) and subgroups diabetic patients with prostheses (Group A1) and nondiabetic patients with prostheses (Group A2). Diabetic patients without prostheses (Group B1) and nondiabetic patients without prostheses (Group B2). Sociodemographic information of each patient was recorded, and clinical examination was performed for decayed, missing, and filled teeth (DMFT) using DMFT index. Results A statistically significant high prevalence of dental caries was observed among nondiabetic patients with acrylic RPD (Group A2). Conclusion Acrylic RPD and diabetes had least role in caries prevalence.

Research on Calculation and Optimization Methods for Tooth Flash Temperature and Meshing Power Loss of the Gear System in Drum Shearer

The operating conditions of the drum shearer are very complex, and its ranging arm gear system often suffers from gear scuffing and wear. Gear scuffing is caused by the adhesive wear, which is due to the instantaneous friction and flash temperature of the tooth surface, and the gear meshing power loss is also caused by tooth surface friction. In order to resist tooth scuffing and improve meshing efficiency of the transmission system, an improved semi-analytical tooth surface flash temperature calculation method was used. The tooth flash temperature status under various working conditions were analyzed in detail. Based on the mechanical model of the shearer drum picks, the load condition of the drum was analyzed. Under these load and boundary conditions, the misalignments of each gear pair in the ranging arm were calculated. The tooth surface load distribution was calculated under the gear misalignments, and then the theoretical tooth surface flash temperature and meshing power loss were determined. Next, the tooth micro-geometry was modified to reduce flash temperature and meshing power loss. The flash temperature distribution pattern of the optimized tooth surface was studied under various working conditions, and the meshing power loss was also obtained. Finally, experiments were conducted to verify the effects of the optimized tooth surface on the friction temperature rise and the effectiveness of the modification method. Tooth surface optimization aimed at reducing tooth surface flash temperature can also effectively reduce meshing power loss, which has a significant effect on gear anti-scuffing and energy saving.

Depression, stress-related disorders and risk for dental caries and periodontitis: A bidirectional and multivariable Mendelian randomization study

AimsOur Mendelian randomization (MR) analysis focused on investigating the bidirectional relationships between major depressive disorder (MDD), anxiety and stress-related disorder (ASRD), and dental caries as well as periodontitis. Materials and methodsWe used summary statistics from two studies: an MDD genome-wide association study (GWAS) including 135,458 cases with 344,901 controls and a Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH) GWAS based on 12,655 ASRD individuals and 19,225 controls from Denmark. GWASs on dental caries and periodontitis were based on the Gene-Lifestyle Interactions in Dental Endpoints (GLIDE) consortium. We employed different MR approaches, such as inverse-variance weighted (IVW), MR–Egger, weighted median, and MR-PRESSO, to calculate causal effects. ResultsSingle-variable MR analysis revealed that ASRD was potentially significantly associated with decayed, missing, and filled tooth surfaces (DMFS) (β = 0.056; 95 % CI: 0.009, 0.103; p = 0.018). Periodontitis was suggested to be causally related to increased ASRD risk (OR = 1.143, 95 % CI: 1.008, 1.298; p = 0.038). According to the multivariable MR analysis, no significant associations were detected between MDD and ASRD with dental caries and periodontitis, and vice versa. ConclusionsASRD demonstrated a potential association with DMFS, and periodontitis was found to potentially impact ASRD according to single-variable MR analysis. Nevertheless, no significant associations were identified between MDD, ASRD, dental caries, or periodontitis after adjusting for smoking status and education level. Hence, more robust genetic instruments are required to validate and reinforce our findings.

A method for determining the actual coordinate system of spiral bevel gears by the measured positions of eight tooth surfaces

Abstract The coordinate system for the measurement of spiral bevel gear (SBG) by gear measuring center (GMC) is discussed and the misalignment between the actual coordinate system and the theoretical coordinate system of the SBG is analyzed. The misalignment can cause measurement errors and cannot be neglected in SBG precision measurements. To calculate the misalignment and accurately establish the actual coordinate system, a novel re-fitting method based on the measured positions of eight tooth surfaces is proposed. First, eight sets of gear axis direction vectors and original points can be obtained from the measurement of eight tooth surfaces, by the single tooth surface matching method. Second, the actual axis vector and the original point of the gear can be obtained, by re-fitting those eight sets of gear axis vectors and original points. Then, the actual coordinate system can be established by the actual gear axis direction vector and the original point. The least square method is used to calculate the original point, and a basis vector fitting method is proposed to solve the gear axis direction vector. Finally, two groups of preset coordinate system deviation tests are carried out to verify the accuracy and feasibility of the fitting algorithm. The results show that the fitting error of the original point is far less than 1 × 10 − 1 μ m and the fitting error of the angle is far less than 1 × 10 − 7 degree, which are superior to the design accuracy of the GMC. Therefore, the proposed algorithm can be applied to improve the measurement accuracy of current GMC.

In-Vitro Evaluation of Shear Bond Strength of Glass Ionomer Cement to Primary Teeth Dentin Pretreated with Silver Diamine Fluoride and Sodium Fluoride Varnish

Aim: To evaluate and compare the shear bond strength (SBS) of glass ionomer cement (GIC) to primary teeth dentin pretreated with silver diamine fluoride (SDF) and sodium fluoride (NaF) varnish. Materials and Methods: A total of 50 non carious human primary molars were used in this study. The teeth were prepared to expose a flat dentin surface, ensuring comparability across samples. The samples were then randomly divided into two groups. Group I: The dentin surface of the primary teeth was pretreated with 38% SDF. Group II: The dentin surface of the primary teeth was pretreated with 5% NaF varnish. Following pretreatment, all samples were restored using GIC. The SBS was evaluated using a universal testing machine, which measures the force required to detach the GIC from the dentin surface. Results: The study found that the mean SBS of Group I (SDF 38%) was significantly higher at 10.11 ± 2.34 MPa compared to Group II (NaF 5%), which had a mean SBS of 6.34 ± 2.56 MPa. This represented a mean difference of 3.77 MPa in favor of the SDF pretreatment group. Conclusion: The primary teeth dentin pretreated with 38% SDF demonstrated a significant increase in SBS to GIC compared to the teeth pretreated with 5% NaF varnish. This suggests that SDF not only acts as a caries-preventive agent but also enhances the bond strength of restorative materials adhered to dentin surfaces. Clinical Significance: The findings hold considerable clinical significance, especially for pediatric dentistry. The use of SDF as a dentin pretreatment can improve the adhesion of GIC to the dentin of primary teeth. This is particularly beneficial given the minimally invasive nature of the procedure, making it an optimal choice for young patients who may find conventional dental procedures distressing. In summary, this study supports the use of SDF over NaF varnish for pretreating primary teeth dentin before GIC restoration, due to the superior bond strength observed. Implementing this can improve the longevity and effectiveness of restorative treatments in primary teeth, offering a viable, simple method that aligns well with pediatric dental care standards.

A high-speed gear reshaping method for electric vehicles combining the effects of input torque and speed variation.

In this study, we introduce an optimization method for high-speed gear trimming in electric vehicles, focusing on variations in input torque and speed. This approach is designed to aid in vibration suppression in electric vehicle gears. We initially use Tooth Contact Analysis (TCA) and Loaded Tooth Contact Analysis (LTCA) to investigate meshing point localization, considering changes in gear tooth surface and deformations due to load. Based on impact mechanics theory, we then derive a formula for the maximum impact force. A 12-degree-of-freedom bending-torsion-axis coupled dynamic model for the helical gear drive in the gearbox's input stage is developed using the centralized mass method, allowing for an extensive examination of high-speed gear vibration characteristics. Through a genetic algorithm, we optimize the tooth profile and tooth flank parabolic modification coefficients, resulting in optimal vibration-suppressing tooth surfaces. Experimental results under various input torques and speeds demonstrate that the overall vibration amplitude is stable and lower than that of conventional gear shaping methods. Specifically, the root mean square of vibration acceleration along the meshing line under different conditions is 58.02 m/s2 and 20.33 m/s2, respectively. The vibration acceleration in the direction of the meshing line is 20.33 m/s2 and 20.02 m/s2 under varying torques and speeds, with 20.33 m/s2 being the lowest. Furthermore, the average magnitude of the meshing impact force is significantly reduced to 5015.2. This high-speed gear reshaping method not only enhances gear dynamics and reliability by considering changes in input torque and speed but also effectively reduces vibration in electric vehicle gear systems. The study provides valuable insights and methodologies for the design and optimization of electric vehicle gears, focusing on comprehensive improvement in dynamic performance.

The mucosal released‐coronally advanced flap: A novel surgical approach—A case report

AbstractBackgroundThe coronally advanced flap (CAF) can be a predictable surgical technique for the treatment of gingival recessions. However, the characteristics of the defect (e.g., limited amount of keratinized gingiva or flap tension, etc.) may limit the use of the CAF with a possible requirement of additional surgical interventions (i.e., the use of a tissue graft to be harvested from donor sites or connective tissue substitutes).MethodsA 28‐year‐old woman patient, with no history of periodontal disease, came for referral presenting receding gums as a chief complaint, poor esthetics, and dentinal hypersensitivity at the buccal surface of teeth 11, 12, and 13. Clinically, she presented a thick phenotype with gingival recession type, RT1, with detectable cemento‐enamel junction (A‒) in the second quadrant. To reduce the need of harvesting soft tissue grafts, the amount of cutting of muscles and vessels from the inner portion of the flap and mitigate the postoperative discomfort associated with the CAF, a novel surgical approach is described here using an advanced flap that incorporates an external incision along the mucogingival junction.ResultsThe average root coverage achieved with the novel procedure presented in this case report was 95%, along with an increased amount of keratinized gingiva and minimal postoperative patient's discomfort.ConclusionsThe mucosal released CAF is a promising technique in which the CAF technique alone may not be an indication.Key pointsThis technique has the following advantages: Reduce the need of harvesting soft tissue grafts. Reduce the amount of cutting of muscles and vessels from the inner portion of the flap. Minimal postoperative discomfort for the patient.

Establishment and evaluation of a 3D quantitative analysis method for dental plaque based on an intraoral scanner technique.

Quantitative dental plaque evaluation is necessary for clinical and scientific work. The present study aimed to examine the reliability of a 3D image analysis method by digitally analyzing the color 3D images obtained from an intraoral scanner (IOS) and then detecting and quantifying the plaque information and comparing it with the clinical examination results. A total of 140 teeth from five subjects with a standard dentition were enrolled. Plaque examination was performed at two different time points: after 24 h without oral hygiene (T1), and after habitual brushing (T2). At each time point, the Quigley-Hein Plaque Index (PI) of each tooth surface was recorded separately, followed by color 3D images obtained using an IOS, and image analysis and calculation using Geomagic Wrap 2021 software. The percentage of plaque staining area calculated from the 3D image analysis correlated well with the PI recorded during the clinical examination: the Spearman correlation coefficients were 0.9136 and 0.9061 (P < 0.001) for all tooth surfaces at T1 and T2, respectively. The measurements of the three investigators were in good agreement, with intraclass correlation coefficients of 0.989 and 0.992 (P < 0.001) for the vestibular and lingual surfaces at T1, respectively, and 0.964 and 0.983 (P < 0.001) for the vestibular and lingual surfaces at T2, respectively. In the present study, a digital 3D evaluation system of dental plaque suitable for research and clinical practice was initially developed and its reliability demonstrated.

Increasing Vertical Dimension of a Case with Full Mouth Rehabilitation: Case Report.

Introduction: Bruxism is one of the most frequent causes for occlusal tooth wear, with the loss of tooth structure caused by mechanical wear between maxillary and mandibular tooth surfaces, case report was conducted to improve the patient oral health, and to maintain the new vertical dimension since it was lost by teeth clenching. Case description: this paper presents a 50 years old male suffering from severe bruxism, which implicated the appearance and function of the patient, he was transferred to TIU dental hospital for full mouth rehabilitation treatment. Discussion: The rehabilitation of patients with extensive occlusal wear is complex and difficult to solve, becoming thus one of the biggest challenges of dentistry, a proper planning of a prosthetic rehabilitation should not attribute the re-establishing of occlusal vertical dimension (OVD) to new prostheses at the risk of the patient doesn’t adapt to a new condition of vertical dimension. Conclusion: Tooth wear causes dimensional changes in facial morphology and OVD decrease. The correct determination of occlusal vertical dimension represents a factor of success in the rehabilitation treatment. Keywords: Vertical Dimension, Rehabilitation, Full Mouth, Bruxism.

Protecting primary teeth from dental erosion through bioactive glass

ObjectivesThe present study aimed to evaluate the effectiveness of bioactive glass (BAG) in preventing dental erosion in primary teeth. MethodsEnamel and dentin specimens (2 × 2 × 2 mm) were obtained from extracted primary teeth, which were randomly divided into the following groups based on the pretreatments (n = 12): DW (deionized water), NaF (2 % sodium fluoride), 2BAG (2 % BAG), 4BAG (4 % BAG), 6BAG (6 % BAG), and 8BAG (8 % BAG). The specimens were immersed in the respective solutions for 2 min and subjected to in vitro erosive challenges (4 × 5 min/d) for 5 d. The erosive enamel loss (EEL), erosive dentin loss (EDL), and the thickness of the demineralized organic matrix (DOM) were measured using a contact profilometer. The surface microhardness (SMH) was measured, and the percentage of SMH loss (%SMHL) was calculated. The surface morphology and mineral composition were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), respectively. ResultsAfter the erosive challenges, the EEL, EDL, and%SMHL of the 2BAG, 4BAG, 6BAG, and 8BAG groups significantly reduced, with the greatest reduction was observed in the 6BAG (EEL: 6.5 ± 0.2 μm;%SMHL in enamel: 12.8 ± 2.6; EDL: 7.9 ± 0.3 μm; %SMHL in dentin: 22.1 ± 2.7) and 8BAG groups (EEL: 6.4 ± 0.4 μm;%SMHL in enamel: 11.0 ± 1.9; EDL: 7.8 ± 0.5 μm; %SMHL in dentin: 22.0 ± 2.5) (P < 0.05). With increasing BAG concentrations, the number of surface deposits containing Ca, P, and Si increased. Conclusions6BAG was the most effective for preventing dental erosion in primary teeth and showed a particularly strong potential for dentin erosion prevention. Clinical SignificanceBioactive glass, especially at a 6 % concentration, has proven effective in reducing erosive tooth wear and surface microhardness loss while also protecting demineralized organic matrix in primary dentin.