Evaluation of the bisphenol released in the saliva after residual adhesive removal in orthodontic patients by using ultrasonic scaling and rotary system: A single-center randomized clinical trial.

INTRODUCTION: Bisphenol A (BPA) is a substance commonly used in dental materials with noxious properties. Monomers of this substance may be dissolved in the saliva and cause adverse effects. This study aimed to evaluate the amount of BPA released in the saliva after residual adhesive removal in orthodontic patients using an ultrasonic scaler (US) and tungsten carbide bur (TCB). METHODS: This single-center randomized clinical trial was conducted on 40 subjects whose stainless-steel brackets were bonded directly with light-cured bonding and composite. The subjects were randomly divided into 2 equal groups (n = 20) of TCB or US according to the adhesive removal method. The salivary BPA level was determined using high-performance liquid chromatography-mass spectrometry. And adhesive cleaning time was measured by a stopwatch. Data were analyzed by SPSS using an independent t test and paired-samples t test (P <0.05). RESULTS: The mean salivary BPA level was significantly lower in the TCB method than in the US method. (1.008 ± 0.061 µg/mL and 2.83 ± 0.24 µg/mL, respectively) (P <0.001). The mean adhesive cleanup time was significantly shorter in the TCB method than in the US method (8.86 ± 0.83 minutes and 13.20±1.02 minutes, respectively) (P <0.001). CONCLUSIONS: According to the results, residual adhesive removal with TCB released less BPA in saliva and shortened the adhesive cleaning time than the US method. TRIAL REGISTRATION: The trial was registered at the Iranian Registry of Clinical Trials (IRCT20200702047988N1). PROTOCOL: The protocol was not published before trial commencement.

Remote clinical consultations in restorative dentistry: a clinical service evaluation study.

Introduction Specialist consultant services in the UK NHS provide a decision-making support service to other health professionals. There is a drive to deliver this service in a more patient-centred, cost-effective and efficient manner. Remote clinical consultations (RCC), using secure, live, super-fast internet connectivity and high-resolution, multi-channel audio-visual streaming, has the potential for the delivery of this service.Aim To conduct a clinical service evaluation to assess the viability and efficiency of conducting a RCC for the management of primary care referrals in restorative dentistry, compared to an in-person consultation.Design A RCC was conducted for every participating patient and immediately followed with a 'verification' in-person consultation.Materials and method Twenty-three patients of even gender distribution participated in this study across the three specialisms of restorative dentistry. A thematic questionnaire was completed by each member of the study intervention team and the patient after each consultation.Results In all the cases, the consultant was able to conduct an effective and safe clinical consultation, not inferior to an in-person process, regardless of gender and age. The GDP, the nurse and the patient were able to participate effectively in the process and with each other.Conclusion This proof-of-concept study suggests that the RCC concept is a feasible way of delivering specialist consultations in restorative dentistry with high levels of patient acceptability and that it can be delivered in a practical and simple manner.

Oral health-related quality of life after prosthodontic treatment for patients with partial edentulism: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Clinicians are currently unable to quantify the psychosocial, functional, and esthetic effects of prosthetic interventions to replace teeth. Understanding the effects of treatment to replace teeth on oral health-related quality of life (OHRQoL) is important for informed consent. A systematic review of the evidence of OHRQoL improvements with prosthodontic tooth replacement and a comparison of outcomes between treatment modalities is therefore indicated. PURPOSE: The purpose of this systematic review was to examine the OHRQoL of patients with partial edentulism after different dental prosthetic treatments. MATERIAL AND METHODS: Electronic database and manual searches were conducted to identify cohort studies and clinical trials reporting on the OHRQoL of individuals receiving implant-supported crowns (ISCs), implant-supported fixed dental prostheses (IFDPs), implant-supported removable dental prostheses (IRDPs), tooth-supported fixed dental prostheses (TFDPs), and removable partial dentures (RPDs). Two reviewers independently conducted article selection, data extraction, and quality assessment. Random-effects models were used to compare OHRQoL change scores (standardized mean change, 95% confidence intervals). RESULTS: Of the 2147 identified studies, 2 randomized controlled trials and 21 cohort studies met the inclusion criteria. Overall, studies were of low or moderate risk of bias. Pooled mean OHRQoL change ≤9 months was 15.3 for TFDP, 11.9 for RPD, and 14.9 for IFDP. Pooled standardized mean change OHRQoL change >9 months was 13.2 for TFDP and 15.8 for IFDP. Direct comparisons ≤9 months between TFDP against IFDP and RPD against IFDP significantly favored IFDP in both cases. CONCLUSIONS: TFDP and IFDP had short- and long-term positive effects on OHRQoL. RPDs positively affected OHRQoL in the short term. IFDP showed greater short-term improvement in OHRQoL than RPD and TFDP.

Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study.

BACKGROUND: Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets. MATERIAL AND METHODS: 120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups. RESULTS: The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems. CONCLUSIONS: The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system. KEY WORDS: Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch.

Effect of surface treatment on stress distribution in immediately loaded dental implants--a 3D finite element analysis.

OBJECTIVE: To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone-implant interface in immediately loaded mandibular implants. MATERIALS AND METHODS: An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (µ); these were either (1) plasma sprayed or porous-beaded (µ=1.0), (2) sandblasted (µ=0.68) or (3) polished (µ=0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (µ=0.4) interfacing with the cortical bone, and a body plasma treated surface component (µ=1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces. RESULTS: This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone-implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant-bone interface. SIGNIFICANCE: The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone-implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results.

Fracture strength of machined ceramic crowns as a function of tooth preparation design and the elastic modulus of the cement.

OBJECTIVES: To determine, by means of static fracture testing the effect of the tooth preparation design and the elastic modulus of the cement on the structural integrity of the cemented machined ceramic crown-tooth complex. METHODS: Human maxillary extracted premolar teeth were prepared for all-ceramic crowns using two preparation designs; a standard preparation in accordance with established protocols and a novel design with a flat occlusal design. All-ceramic feldspathic (Vita MK II) crowns were milled for all the preparations using a CAD/CAM system (CEREC-3). The machined all-ceramic crowns were resin bonded to the tooth structure using one of three cements with different elastic moduli: Super-Bond C&B, Rely X Unicem and Panavia F 2.0. The specimens were subjected to compressive force through a 4mm diameter steel ball at a crosshead speed of 1mm/min using a universal test machine (Loyds Instrument Model LRX.). The load at the fracture point was recorded for each specimen in Newtons (N). These values were compared to a control group of unprepared/unrestored teeth. RESULTS: There was a significant difference between the control group, with higher fracture strength, and the cemented samples regardless of the occlusal design and the type of resin cement. There was no significant difference in mean fracture load between the two designs of occlusal preparation using Super-Bond C&B. For the Rely X Unicem and Panavia F 2.0 cements, the proposed preparation design with a flat occlusal morphology provides a system with increased fracture strength. SIGNIFICANCE: The proposed novel flat design showed less dependency on the resin cement selection in relation to the fracture strength of the restored tooth. The choice of the cement resin, with respect to its modulus of elasticity, is more important in the anatomic design than in the flat design.

Effect of the crown design and interface lute parameters on the stress-state of a machined crown-tooth system: a finite element analysis.

The effect of preparation design and the physical properties of the interface lute on the restored machined ceramic crown-tooth complex are poorly understood. The aim of this work was to determine, by means of three-dimensional finite element analysis (3D FEA) the effect of the tooth preparation design and the elastic modulus of the cement on the stress state of the cemented machined ceramic crown-tooth complex. The three-dimensional structure of human premolar teeth, restored with adhesively cemented machined ceramic crowns, was digitized with a micro-CT scanner. An accurate, high resolution, digital replica model of a restored tooth was created. Two preparation designs, with different occlusal morphologies, were modeled with cements of 3 different elastic moduli. Interactive medical image processing software (mimics and professional CAD modeling software) was used to create sophisticated digital models that included the supporting structures; periodontal ligament and alveolar bone. The generated models were imported into an FEA software program (hypermesh version 10.0, Altair Engineering Inc.) with all degrees of freedom constrained at the outer surface of the supporting cortical bone of the crown-tooth complex. Five different elastic moduli values were given to the adhesive cement interface 1.8GPa, 4GPa, 8GPa, 18.3GPa and 40GPa; the four lower values are representative of currently used cementing lutes and 40GPa is set as an extreme high value. The stress distribution under simulated applied loads was determined. The preparation design demonstrated an effect on the stress state of the restored tooth system. The cement elastic modulus affected the stress state in the cement and dentin structures but not in the crown, the pulp, the periodontal ligament or the cancellous and cortical bone. The results of this study suggest that both the choice of the preparation design and the cement elastic modulus can affect the stress state within the restored crown-tooth complex.

Effect of self-etching primer/adhesive and conventional bonding on the shear bond strength in metallic and ceramic brackets.

INTRODUCTION: Bracket debonding from the tooth surface is a common problem in fixed orthodontics. The aims of the present study were to assess the bond strength and failure sites in two ways of bonding technique, with metallic and ceramic brackets. MATERIALS AND METHODS: One hundred premolars were assigned to 4 groups of 25 each: Group A, metallic brackets/conventional procedure; Group B, metallic brackets/Transbond XT; Group C, ceramic brackets/conventional procedure; and Group D, ceramic brackets/Transbond XT. Transbond XT composite paste was used for bracket bonding and cured by conventional light-cure device. Specimens were subjected to thermocycling. One week after bonding shearing force was applied to the bracket-tooth interface. Bonding failure site optically examined using a stereomicroscope under 10 × magnifications and scoring was done using the adhesive remnant index (ARI). Data were subjected to analysis of One-way variance, Tukey post hoc, Chi-square and Spearman's tests. RESULTS: Mean bond strength (in MPa) were: group A=9.2, group B=8.5, group C=6.2 and group D=5.7. Bond strength differences between groups A and B, and between C and D were not significant, (p<0.0005). Insignificant difference found in ARI in all groups. CONCLUSION: The bond strengths of metallic brackets were significantly higher than ceramic ones and the self-etching primer produce fewer bonds than the conventional method (clinically acceptable).A positive correlation found between changes in shearing bond strength and ARI.

Effect of psychological stress on orthodontic tooth movement in rats.

INTRODUCTION: The purpose of this study was to investigate the effect of psychological stress on orthodontic tooth movement in Wistar rats. MATERIALS AND METHODS: Forty-eight female ten-week old Wistar rats with an average weight of 188 ±12 gr were selected and randomly divided into two experimental and control groups. The experimental group received crowded environment-induced and cat odour stresses 4 weeks before spring insertion. On the 29th day in both groups, maxillary incisors were moved by the insertion of springs and exactly after 7 days, 9 rats from each group and after 14 days the remaining rats were sacrificed. Then the mesioincisal distance between maxillary incisors was measured. Afterwards, histological sections were prepared to count osteoclasts under a light microscope. The data on the extent of orthodontic tooth movement and the number of osteoclasts were analyzed by independent sample t-test. RESULTS: The results indicated that on the 7th day after spring placement the orthodontic tooth movement was significantly higher in the control group compared to the experimental group (p<0.05). The number of osteoclasts at a significance level of α=0.1 in the control group was higher compared to the experimental group. On the 14th day after spring placement, the orthodontic tooth movement in the control group was significantly higher compared to the experimental group (p<0.05). However, there were no significant differences in the number of osteoclasts between the two groups. The rats experienced weight loss in the experimental group (p<0.05). CONCLUSIONS: Psychological stress led to a decrease in orthodontic tooth movement and in the number of osteoclasts around the root in the movement direction in rats, but a decrease in osteoclast counts was not parallel with time and demonstrated a nonlinear pattern. In addition, psychological stress led to weight loss in rats.

Determining tooth size ratio in an Iranian-Azari population.

AIM: The aim of this investigation was to determine the tooth size ratio in an Iranian-Azari population. METHOD AND MATERIALS: The Bolton tooth size analysis was performed on a sample of 50 plaster models (25 male subjects, 25 female subjects) of Iranian-Azari subjects. The mesiodistal widths of all teeth were obtained and the Bolton anterior ratio and overall ratio were calculated. The mean, range, and standard deviation were calculated for the anterior and overall ratio, and a coefficient of variation was obtained for the tooth size ratio. RESULTS: For the anterior ratio (3-3), the Iranian-Azari had a mean of 78.0 mm with a standard deviation of 3.1; the range was 73.68 to 84.6 mm. For the overall ratio (6-6), the mean was 92.0 mm with a standard deviation of 2.4; the range was 88.09 to 97.5 mm. CONCLUSIONS: The results from the Iranian-Azari subjects in the study are similar to Bolton's original data for an American population. These values and the degree of variation were similar to the original data by Bolton, indicating the Bolton analysis for Caucasian samples can be transferred to an Iranian-Azari population. It also confirms no relevant sexual dimorphism exists, and these values are valid for both male and female subjects.