Assessment of dimensional stability of novel VPES impression material at different time intervals with standard disinfectants.

BACKGROUND: Vinyl polyether silicone (VPES) is a novel impression biomaterial made of a combination of vinyl polysiloxane (VPS) and polyether (PE). Thus, it is significant to assess its properties and behaviour under varied disinfectant test conditions. This study aimed to assess the dimensional stability of novel VPES impression material after immersion in standard disinfectants for different time intervals. METHODS: Elastomeric impression material used -medium body regular set (Monophase) [Exa'lence GC America]. A total of 84 Specimens were fabricated using stainless steel die and ring (ADA specification 19). These samples were distributed into a control group (n=12) and a test group (n=72). The test group was divided into 3 groups, based on the type of disinfectant used - Group-A- 2% Glutaraldehyde, Group-B- 0. 5% Sodium hypochlorite and Group-C- 2% Chlorhexidine each test group was further divided into 2 subgroups (n=12/subgroup) based on time intervals for which each sample was immersed in the disinfectants - subgroup-1- 10 mins and Subgroup 2- 30 mins. After the impression material was set, it was removed from the ring and then it was washed in water for 15 seconds. Control group measurements were made immediately on a stereomicroscope and other samples were immersed in the three disinfection solutions for 10 mins and 30 mins to check the dimensional stability by measuring the distance between the lines generated by the stainless steel die on the samples using a stereomicroscope at x40 magnification. RESULTS: The distance measured in the control group was 4397.2078 µm and 4396.1571 µm; for the test group Group-A- 2% Glutaraldehyde was 4396.4075 µm and 4394.5992 µm; Group-B- 0. 5% Sodium hypochlorite was 4394.5453 µm and 4389.4711 µm Group-C- 2% Chlorhexidine was 4395.2953 µm and 4387.1703 µm respectively for 10 mins and 30 mins. Percentage dimensional change was in the range of 0.02 - 0.25 for all the groups for 10 mins and 30 mins. CONCLUSIONS: 2 % Glutaraldehyde is the most suitable disinfectant for VPES elastomeric impression material in terms of dimensional stability and shows minimum dimensional changes as compared to that of 2% Chlorhexidine and 0.5% Sodium hypochlorite.

Estimating Ni, Cr, Co, and Mo release from 3 dental casting alloys in saliva and blood at 6 and 12 months by using inductively coupled plasma mass spectroscopy.

STATEMENT OF PROBLEM: The leaching of elements from long-term definitive prostheses, with saliva acting as an electrolyte, poses a biological concern. The approximate concentration in the biological samples that are considered clinically toxic ranges from 1 to 5000 nmol/L for Cr and Co, 1 to 200 nmol/L for Ni, and 1 to 20 nmol/L for Mo. While in vitro studies are available regarding the leaching of elements in artificial saliva, solutions containing protein, solutions of different pH, and different culture media, the in vivo effects of leaching in the biological sample with increasing time are unknown. PURPOSE: The purpose of this clinical study was to quantify the Ni, Co, Cr, and Mo metals in saliva and blood before and after restoration with prostheses made from 3 different brands of dental casting alloy at 6 and 12 months. MATERIAL AND METHODS: Three popular brands of Ni-Cr alloy with different compositions were evaluated. A total of 150 participants requiring a definitive prosthesis were enrolled and divided into 3 groups (n=50). Heavy metal levels from saliva and blood were measured by using the inductively coupled plasma mass spectroscopy method before cementation of the prosthesis and after 6 and 12 months. RESULTS: The presence of Ni in saliva was in the range of 10.34 to 12.12 µg/L, Cr was 1.04 to 1.22 µg/L, and Mo was 1.04 to 1.08 µg/L over a period of 6 and 12 months after cementation of the metal prosthesis. The presence of Ni in blood was in the range of 6.35 to 14.45 µg/L and that of Cr was 9.09 to 16.16 µg/L over a period of 6 and 12 months after cementation. Co levels were not detected from any brands in saliva or blood, and Mo was detected only in the saliva samples. CONCLUSIONS: Increased levels of Ni and Cr in saliva and blood from all 3 brands of base metal alloy at 6 and 12 months were observed at higher than threshold values.

Effectiveness of the photobiomodulation therapy using low-level laser around dental implants: A systematic review and meta-analysis.

BACKGROUND: The photobiomodulation (PBM) therapy has been applied in various fields. Its use in implant dentistry has been proven through various animal, in vitro, and recently also clinical studies. However, the cumulative data of its effect around dental implants in patients is limited. OBJECTIVES: The purpose of the present study was to evaluate whether or not the PBM therapy has a positive effect around dental implants and on implant stability. MATERIAL AND METHODS: The studies included in the review and meta-analysis were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the PICOS criteria. The RoB 2 tool was used for assessing the risk of bias and the RevMan software, v. 5.0, was used for meta-analysis. Quantitative analysis was done considering the implant stability measurement as the outcome. The mean and standard deviation (M ±SD) values for implant stability as well as the sample size were extracted from the articles, and the inverse variance method with random effects was used for meta-analysis. The forest plots for all time intervals were inspected to estimate the heterogeneity by assessing the I2 statistic. RESULTS: A total of 148 articles were initially retrieved, out of which 81 remained after duplicate removal. Ten articles were included in the review after rejecting 68 on the basis of title and abstract. Seven were eligible for quantitative analysis. The meta-analysis showed non-significant differences in primary stability in control and laser groups at baseline (p = 0.63) and 3 months and above (p = 0.06). At 2 weeks, 1 month and 2 months, the results were statistically significant with p = 0.01, p = 0.02 and p = 0.04, respectively. CONCLUSION: The PBM therapy showed a positive effect on implant stability during the early stages of healing and can be considered for patients with dental implants.

Comparative evaluation of frictional resistance of extracoronal attachments of different designs and lengths in fixed partial denture: A finite element analysis.

Aim: The purpose of the study was to evaluate the frictional resistance and the vertical force required to achieve the frictional resistance for different length and designs of extracoronal attachments used in fixed partial denture (FPD). Setting and Design: Finite element analysis. Materials and Methods: Four different designs and five different lengths (3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm) of extracoronal attachments for FPD were selected from different manufacturers. Three-dimensional models of all the samples were simulated using Catia V5 software. The properties were incorporated to the software to simulate the clinical conditions. The frictional resistance and the vertical force required to achieve frictional resistance were analyzed using ANSYS workbench 15.0 finite element software. Statistical Analysis Used: ANOVA and Tukey's post hoc test. Results: The mean microhardness of the Variolink N resin cements were significantly higher than Panavia SA ones (P < 0.001). Variolink N cements exhibited lower sorption/solubility than Panavia SA resin cements (P < 0.05). The ceramic shade had a significant influence on the microhardness of both cements (P < 0.001) but had no significant effect on the sorption/solubility of resin cements (P > 0.05). Conclusion: Interposition of monolithic zirconia decreases the microhardness of resin cement especially Panavia SA. The microhardness decreased in Variolink N with the increase in the chroma saturation of ceramics. However, in Panavia SA, it was altered by the shades. For both cements, there were no statistical differences between the sorption/solubility. There was a reverse correlation between microhardness and water sorption/solubility of both cements.

Anchored guided rehabilitation.

The loss of mandibular continuity leads to difficulty in swallowing, problems in mastication, altered mandibular movement, impaired speech articulation, and cosmetic disfigurement. Rehabilitation of such patients becomes more challenging in the case of complete edentulous maxillary and mandibular arches due to a lack of support and anchorage. This case report describes prosthetic rehabilitation of completely edentulous arches with segmental mandibulectomy. Hence, the anchorage was provided with the help of osseointegrated implants in both the maxillary and mandibular arches. Deviation of the mandible toward the unresected side during mastication and other functions was corrected using a palatal ramp. An attempt was made for prosthetic rehabilitation of mandibulectomy defect which required a multidisciplinary approach and which fulfilled the patient's requirement of mastication.

Evaluation of the effect of ultraviolet light polymerized clear adhesive on shear and tensile bond strength of heat cure denture base resin to the cobalt-chromium retentive minor connector: An in vitro study.

AIM: The aim of this study is to evaluate the efficacy of new material ultraviolet (UV) light polymerized clear adhesive on shear and tensile bond strength of heat cure denture base resin (Polymethylmethacrylate (PMMA)) to cobalt-chromium (Co-Cr) retentive minor connector. SETTING AND DESIGN: Comparative evaluation- In-vitro study. MATERIALS AND METHODS: Sixty samples of Co-Cr plates mimicking minor connectors were fabricated. Thirty samples were coated with new material UV light polymerized clear adhesive and cured under UV light source for 10 min. In gun-metal flask, metal plates were placed in the lower compartment over it. Heat cure acrylic resin was packed in the dough stage with the help of clamps and processed according to the manufacturer's instructions. Samples were kept in artificial saliva for 90 days. Shear and tensile bond strengths were calculated of each sample with a Universal testing machine, and results were statistically analyzed. Type of bond failure was observed for each sample under stereomicroscope. STATISTICAL ANALYSIS USED: Unpaired t test. RESULTS: Tensile bond strength, as well as shear bond strength, showed that 0.93 N and 1.64 N respectively for without application of new adhesive was more as compared to that of samples with the application of new adhesive which is 0.75 N and 1.54 N respectively. Bond failure was found to be an adhesive failure in resin-metal interface. CONCLUSIONS: Excellent bonding seen between the new adhesive and acrylic interface but limited effect on the metal interface. To increase bond strength between metal and resin interface, some surface treatment with the metal surface is needed to increase the bonding of the new adhesive to the metal surface.

A split-mouth clinico-radiographic comparative study for evaluation of crestal bone and peri-implant soft tissues in immediately loaded implants with and without platelet-rich plasma bioactivation.

Background. This study evaluated the viability of platelet-rich plasma for enhancement of osseous and associated soft tissue healing around single-piece implants, subjected to immediate loading and to compare it with a control site not treated with PRP. Methods. Twenty completely edentulous patients were selected and 2 one-piece implants with O-ball head were placed for mandibular overdenture. The implant on the right side was treated with PRP whereas the left side implant served as a control. All the cases were immediately loaded and marginal bone loss, probing depth, percussion, implant mobility and peri-implantitis were assessed and compared at 3, 6, 9 and 12 months. Results. Overall analysis of the results showed less marginal bone loss, probing depth, percussion, implant mobility and periimplantitis around implants treated with PRP; however, the results were insignificant statistically. Conclusion. PRP can be used as a viable treatment adjunct in immediately loaded one-piece implants.

A clinical comparative study to assess the efficacy of a new centric registration technique with a conventional technique.

AIM: The aim and objectives of this study were to assess and compare the efficacy of a new copyrighted technique (wax ball technique, L-77997/2018) and design (denture base design for the wax ball technique, L-78006/2018) for recording centric relation (CR). SETTINGS AND DESIGNS: In vivo - comparative study. MATERIALS AND METHODS: This study was conducted on sixty consented edentulous patients. The study participants were divided into Group I and Group II. CR in Group I patients was recorded using Dawson's bimanual technique (technique 1). For participants in Group II, CR was recorded using the authors' copyrighted technique (technique 2). Time taken and accuracy of CR records by both the techniques were evaluated. STATISTICAL ANALYSIS USED: Descriptive statistics such as frequency and percentage were calculated for categorical variables, mean and standard deviation were calculated for quantitative variables. Independent t-test was used to compare the time taken to record the CR between the two groups. The accuracy of both the techniques was assessed by Mann-Whitney U-test. RESULTS: The mean time taken for technique 1 was 56.47 s, whereas for technique 2, it was 5.97 s, with an overall mean difference of 50.5 s between the two techniques. Both techniques were found to be accurate, as the CR recorded during jaw relation matched with CR during trial in all the cases in both the groups (frequency 30 (N) and cumulative percentage 100%). CONCLUSION: From the study, it was found that, time taken for technique 2 was statistically less compared to that of technique 1, and both the techniques were found to be equally accurate.

An In vitro Comparative Evaluation of Disinfectants on Standard and Clinical Microbial Strains on Heat Cure Resins.

INTRODUCTION: Oral cavity is colonised by numerous micro-organisms that form a biofilm on the acrylic resin. Hence, routine hygiene is essential to prevent oral mucosal inflammation and lesions. Knowledge of appropriate disinfecting agents for acrylic resins is crucial in this context. AIM: To compare and evaluate the effectiveness of four commercially available disinfectants on heat cure acrylic resin specimens contaminated with standard and clinical strains of two micro-organisms commonly inhabiting the oral microflora. MATERIALS AND METHODS: Two hundred acrylic resin specimens (n=200), 10 in each group were contaminated in vitro with 1x106 cells/ml suspensions of standard and clinical strains of micro-organisms (Candida albicans and Streptococcus mutans) and were immersed in four disinfectants (1% sodium hypochlorite, 2% chlorhexidine digluconate, 2% glutaraldehyde and 3.8% sodium perborate) for 10 minutes. The control group was not subjected to any disinfection process. For collection of clinical strains, oral swab was passed over the buccal mucosa and grown on blood agar culture media. Organism confirmation was done by growing them on selective culture media. Final counts of micro-organisms per ml were performed by plating method for evaluation of microbial level reduction. Results obtained were subjected to ANOVA and Tukey's test. RESULTS: Standard strains of Candida albicans (C) and Streptoccocus mutans (S) subjected to various disinfectants showed varied mean Colony Forming Units per ml (CFU/ml) from <10,000 to 25,000 and <10000 to <50,000 respectively. Clinical strains and of Candida albicans (C) and Streptococcus mutans (S) subjected to various disinfectants showed varied mean CFU/ml from <10,000 to 50,000 and from 10,000 to 50,000 respectively. Control groups showed maximum mean CFU/ml (>105). All intergroup comparisons were highly significant (p<0.001; HS) and intragroup comparisons were significant (p<0.05; S) except the comparison of clinical strains of Streptococcusmutans subjected to 2% chlorhexidine digluconate and 2% glutaraldehyde which was found to be non significant (p>0.05; NS). CONCLUSION: Almost 1% sodium hypochlorite was found to be the most effective disinfectant for both Candida albicans and Streptococcus mutans. The least effective disinfectant being: 3.8% sodium perborate.

"Nature cures:" An alternative herbal formulation as a denture cleanser.

BACKGROUND: Candida albicans is one of the microorganisms which harbor the oral cavity, especially in elderly. However, the incidence of existence of this increases in patients using removable dental prosthesis. There is therefore a need to test the anticandidal efficacy of these cost-effective, easily available products to be used as routine denture cleansers. AIM AND OBJECTIVES: (1) To evaluate antifungal properties of triphala churna on the heat cure denture base material. (2) To evaluate the antifungal effect of chlorhexidine gluconate on the heat cure denture base material. (3) To compare the antifungal effect of triphala churna and chlorhexidine gluconate with a control. (4) To evaluate which among triphala churna and chlorhexidine gluconate has a better antifungal property on the heat cure denture base material. MATERIALS AND METHODS: Study population consisted of sixty dentures wearers from those attending the Outpatient Department of Prosthodontics of the School of Dentistry, Krishna Institute of Medical Sciences Deemed University, Karad. Swabs were collected from the dentures before and after the use of triphala and chlorhexidine. The swabs were cultured on Sabouraud dextrose agar and the total Candida counts were determined. CONCLUSION: Triphala as an antifungal is shown to have more efficacy than the conventional chlorhexidine mouthwash. Résumé Arrière-plan: Candida albicans est l'un des micro-organismes qui abritent la cavité buccale surtout chez les personnes âgées. Cependant, l'incidence de l'existence de cette augmentation chez les patients utilisant des prothèses dentaires amovibles. Il est donc nécessaire de tester l'efficacité anticancédique de ces produits rentables et faciles à utiliser pour être utilisés comme nettoyants de routine pour prothèses dentaires. Buts et Objectifs: (1) Évaluer les propriétés antifongiques de Triphala churna sur le matériau de base de la prothèse thermo-durcissable. (2) Évaluer l'effet antifongique du gluconate de chlorhexidine sur le matériau de base de la prothèse thermo-durcissable. (3) Comparer l'effet antifongique de Triphala churna et du gluconate de chlorhexidine avec un témoin. (4) Évaluer lequel parmi Triphala churna et le gluconate de chlorhexidine a une meilleure propriété antifongique sur le matériel de base de la prothèse de durcissement à chaud. Matériaux et Méthode: La population de l'étude était constituée de soixante porteurs de prothèses dentaires de ceux qui fréquentaient le Département de Prosthodontie de l'École des Sciences Dentaires de l'Institut Krishna des Sciences Médicales de l'Université de Karad. Des prélèvements ont été effectués sur les prothèses avant et après l'utilisation de Triphala et de chlorhexidine. On a cultivé les écouvillons sur de l'agar Sabouraud dextrose et on a déterminé le nombre total de candida. CONCLUSION: Triphala comme un anti fongique est démontré pour avoir plus d'efficacité que le lavage de la bouche classique chlorhexidine.

Use of heat cure clear acrylic as a permanent denture base material: a case report

Clear acrylic denture base material finds is use in the fabrication of implant guides, surgical stents, and guiding flanges in dentistry. Given its excellent transparent property, the material will show the original gingival pigmentation which mimics the natural gingiva. In this case report one such attempt was made to use the clear acrylic denture so as to reflect the patients' original gingival pigmentation.