Internal and Marginal Fit Accuracy of Pre-sintered CAD/CAM Implant-Supported Frameworks Before and After Porcelain Layering.

PURPOSE: Internal and marginal fit accuracy of an implant-supported fixed partial denture (I-FPD) along with passive fit are required for long-term clinical success. This study compared the fit accuracy of three-unit CAD/CAM-fabricated cementretained I-FPDs milled from pre-sintered cobalt-chromium (Co-Cr) and zirconia (Zr) and evaluated the effect of applying porcelain. MATERIALS AND METHODS: Two implant analogs were positioned parallel at first premolar and first molar sites in an acrylic model. Their corresponding abutments were tightened with 25-Ncm torque force. Four groups were designed: two groups of I-FPD frameworks with pre-sintered Zr (ZrF) and soft millable Co-Cr alloy (SF) blocks, and two groups by applying porcelain to the Co-Cr (SP) and Zr (ZrP) frameworks (n = 4 in each group). Absolute marginal gap (AMG), marginal gap (MG), and internal discrepancies were measured. Kolmogorov-Smirnov, Levene, one-way analysis of variance (ANOVA), and Scheffe tests were used for statistical analysis using SPSS software version 22 at a significance level of .05. RESULTS: All measured criteria were significantly different from each other (all P values < .001). The rankings from the lowest gap to the highest gap for the main criteria were as follows: MG: SF < SP < ZrF < ZrP; AMG and internal discrepancies: SF < SP < ZrP < ZrF. Comparing molars and premolars, molars had smaller MGs, larger internal discrepancies, and smaller AMG in ZrP but larger AMG in SP. CONCLUSION: All three-unit CAD/CAM-fabricated cement-retained I-FPDs were in the clinically acceptable range of fit accuracy. The lowest and highest misfit values were observed in the SF and ZrF groups, respectively.

Role of laser or photodynamic therapy in treatment of denture stomatitis: A systematic review.

STATEMENT OF PROBLEM: Denture stomatitis (DS) is an inflammatory oral lesion that occurs mostly in elderly denture wearers and that can negatively affect their quality of life. The conventional treatment plan for DS is topical or systemic fungicidal drug therapy, which are not without side effects. PURPOSE: The purpose of this systematic review was to evaluate the clinical outcomes of using low-level laser therapy (LLLT) or photodynamic therapy (PDT) in the treatment of DS by reviewing high-quality published articles. MATERIAL AND METHODS: The Cochrane Library, Web of Science, Google Scholar, PubMed, ProQuest, Scopus, Embase, and Ovid databases were searched using appropriate key words. Related titles and abstracts published up to May 2017 were screened and selected based on defined inclusion criteria. The full texts of all selected articles were read, and citation lists were checked for missing references. All randomized controlled trials (RCT) were subjected to quality assessments. RESULTS: A total of 760 articles were included in the study after the initial search. Six studies were selected for assessment of eligibility, and 4 of them were sufficiently reliable in methodology and randomization to be included in the study. The applied wavelength varied from 455 nm to 830 nm. Also, the highest energy patients were exposed to was 122 J/cm2, and the lowest was 1 J/cm2. Exposure times ranged from 10 seconds to 26 minutes in the reviewed studies. CONCLUSIONS: Based on the available RCTs, LLLT has a significant role in the clinical treatment of DS. However, the results of PDT were similar to those of conventional antifungal therapies.

Effect of conventional and contemporary disinfectant techniques on three peri-implantitis associated microbiotas.

PURPOSE: To evaluate the antiseptic properties of five different disinfectant techniques on three different peri-implantitis (PI) associated biofilms. METHODS: 90 implant titanium disks, with the same thickness and diameter, were prepared and randomly divided into 18 groups (n = 5) based on the microbiota strains (S. aureus, S. epidermidis and C. albicans) and using the following disinfectant techniques:soft laser therapy, photodynamic therapy (PDT), 0.12% NaOCl, 0.2% chlorhexidine, 3% H2O2, and control groups. After forming a protein layer on disk surfaces, the specimens were exposed to the microbial suspensions. After decontamination according to designated techniques, 2% Trypsin protease was administered to isolate the surviving microorganisms. Muller Hinton agar culture was used for microbiota growth. After 48-hour incubation, the standard colony forming unit (CFU) was assayed and the collected data were analyzed by Kruskal-Wallis and Mann-Whitney tests at a significance level of 0.05. RESULTS: The highest amount of CFU/ml values was shown by C. albicans, which was subjected to PDT (25.12 ± 30.23). The least disinfecting efficacy on S. epidermidis was demonstrated by the laser group (all P-values ≤ 0.01). Nevertheless, all of the groups exhibited significant differences with the control groups (all P-values < 0.01). CLINICAL SIGNIFICANCE: None of the studied disinfectant techniques had the highest lethal effects on all of the tested microbiotas. Therefore, a combination of these disinfectant techniques, for instance PDT ⁺ 3% H2O2 or 0.2% chlorhexidine, is recommended.

A brief review on the efficacy of different possible and nonpharmacological techniques in eliminating discomfort of local anesthesia injection during dental procedures.

Dental anxiety and fear of needle injection is one of the most common problems encountered by dental practitioners, especially in the pediatric patient. In consequences, it might affect the patient's quality of life. Several methods are suggested to lower the discomfort of local anesthesia injection during dental procedures. Desensitization of injection site is one of the recommended strategies. Among chemical anesthetic topical agents that are effective but might have allergic side effects, using some nonpharmacological and safe techniques might be useful. This study aimed to overview the efficacy of using cooling techniques, mostly by ice or popsicles, warming or pH buffering of drug, and using modern devices to diminish the discomfort of local anesthesia injection during dental procedures.

Temporomandibular Joint Hypermobility Manifestation Based on Clinical Observations.

BACKGROUND: Joint range of motion might affected by some factors like laxity and increase joint mobility. Generalized joint hypermobility and temporomandibular joint hypermobility (TMJH) are reported as risk factors for temporomandibular disorders. The aim of this study was to survey the etiological factors of TMJH and its relations to habitual status. MATERIALS AND METHODS: In this cross-sectional descriptive study, 69 patients with TMJH were involved. After profiling personal information and medical history, the patients were divided into three groups based on their maximum mouth opening (MMO) as follow: (Light) MMO of 50-55 mm, (moderate): MMO between 55 and 65 mm, (severe) MMO >65 mm. For subjective observations, patients were asked to fill the prepared questionnaire. The objective evaluations conducted by a specialist. Finally, all the data subjected Chi-Square test by using SPSS software version 22 at a significant level of 0.05. RESULTS: TMJH was more common in women (74.2%). The light group had significant differences with other groups in the discomfort of TMJ and TMJ sound (P < 0.05). Furthermore, sever group manifested highest percentage of masticatory pains, significantly (P < 0.05). CONCLUSION: It can be concluded that pain in TMJ would have a correlation with MMO.

Efficacy of Different Techniques for Removing Debris from Endodontic Files Prior to Sterilization.

BACKGROUND: Dental instruments, like endodontic files, are hardly disinfected. The aim of this study was to evaluate the efficacy of mechanical, chemical, and ultrasonic (in combinations or separately) techniques for removing debris from files, prior to sterilization. MATERIALS AND METHODS: Totally, 90 new endodontic files with size of 15, 25, and 40 (30 files of each one) were sterilized and one files of each one kept as negative control (NC) group. The rest of files (29 files of each size) were divided into five groups after endodontic therapies and prior to autoclaving: (Positive control [PC]: Without interventions, A: Cleaned with scouring sponge soaked in chlorhexidine 0.2%, B: Stored in Micro 10 enzyme, C: Subjected to Micro 10 enzyme in both conventional and ultrasonic way for 15 min, D: Decontaminated by Micro 10 enzyme with ultrasonic). Finally, the samples were observed under a metallographic microscope, and the data were analyzed by Tuckey, paired t-test, two-way ANOVA tests using SPSS software version 15 at a significant level of 0.05. RESULTS: Significant differences were observed in heads of the files among groups C and PC (P = 0.02), and high amount of debris were seen in the shafts of groups A and D (P < 0.001). The amount of remaining debris were significant in the shafts of sizes 15 (P < 0.001) and 25 (P = 0.01). CONCLUSION: Using Micro 10 in both ultrasonic and conventional methods were acceptable for removing debris from the files. Furthermore, higher amounts of debris were found in the shafts and heads of files with lower sizes (15 and 25).

Comparing the Accuracy of Three Different Impression Materials in Making Duplicate Dies.

BACKGROUND: Marginal adaptation is very important in cast restorations. Maladaptation leads to plaque retention, reduction of mechanical and esthetic properties. The aim of this study was to evaluate the precision of three different impression materials (including: Additional silicone [AS] and condensational silicone [CS] and polyether [PE]) for duplicating master dies. MATERIALS AND METHODS: Three master dies from an acrylic tooth model-with supragingival and shoulder finishing line was made by using PE: Impergum, CS: Speedex, and AS: Panasil separately. The Ni-Cr copings were prepared from master dies separately. They were placed on the acrylic model and the mean marginal difference was recorded by using a stereomicroscope. Then 30 duplicate test dies were made by using the same impression materials and the marginal gaps were recorded. The comparison was done by one-way ANOVA and SPSS software (Version 13) at a significant level of 0.05. RESULTS: The mean marginal difference of four walls from Impergum (38.56 um) was the lowest than Speedex (38.92 um) and Panasil (38.24 um). The Impergum had the highest capability in making duplicate dies (P > 0.05). CONCLUSION: The Impergum impression material manifested the highest capability in making a better marginal adaptation of duplicate dies but further studies are needed to make a precise decision.

A Mini-review on the Effect of Mini-implants on Contemporary Orthodontic Science.

The purpose of this literature review was to screen the valuable published articles regarding to the impacts of mini-implants on orthodontic science, briefly. The searching category was performed on the Pubmed using MeSH words such as "dental (mini) implants, orthodontic anchorage procedures, and orthodontic appliances." After preliminary sketch, they were grouped as follow: Those evaluating (a) common appliances for providing orthodontic anchorage, (b) biomechanical details of mini-implants and their insertion, (c) clinical application of mini-implants for orthognathic treatments, (d) limitations and possible complications. In conclusion, mini-implant evolved the orthodontic treatment plans and compromised the required orthognathic surgery. Malocclusion treatment and pure orthodontic or orthopedic movements in the three-dimensions have become recently possible by using mini-implant to provide skeletal anchorage.

Comparing three different three-dimensional scaffolds for bone tissue engineering: an in vivo study.

INTRODUCTION: Three-dimensional Scaffold structure of synthetic biomaterials with their interconnected spaces seem to be a safe and effective option in supporting bone regeneration. The aim of this animal study was to compare the effectiveness of three different biocompatible scaffolds: bioglass (BG), demineralized bone matrix (DBM) and forstrite (FR). MATERIALS AND METHODS: Four healthy dogs were anesthetized and the first to fourth premolars were extracted atraumatically in each quadrant. After healing, linear incision was prepared from molar to anterior segment and 4 defects in each quadrant (16 defects in each dog) were prepared. Scaffold blocks of BG, DBM and FR were resized according to size of defects and placed in the 12 defects randomly, 4 defects remained as control group. The dogs were sacrificed in 4 time intervals (15, 30, 45 and 60 days after) and the percentage of different types of regenerated bones (lamellar and woven) and connective tissue were recorded in histological process. The data were analyzed by one-way ANOVA and post hoc using SPSS software Ver. 15 at significant level of 0.05. RESULTS: In day 30th, although the amount of regenerated lamellar bone in control, DBM and BG Scaffold (22.37±3.44; 21.46±1.96; 21.21±0.96) were near to each, the FR Scaffold provided the highest amount of lamellar (29.71±7. 94) and woven bone (18.28±2.35). Also, FRS caffold showed significant difference with BG (p=0.026) and DBM Scaffolds (p=0.032) in regenerated lamellar bone. CONCLUSION: We recommend paying more attention to FR Scaffold as a biomaterial, but it is better to be compared with other nano biomaterials in future studies.

Posterior open occlusion management by registration of overlay removable partial denture: A clinical report.

This clinical report describes prosthetic rehabilitation of posterior open bite relationship in a patient with several missing teeth and skeletal Class III malocclusion. Primary diagnostic esthetic evaluations were performed by mounting casts in centric relation and estimating lost vertical dimension of occlusion. Exclusive treatments were designated by applying overlay removable partial denture with external attachment systems for higher retentions.

The effect of eugenol-free temporary cement's remnants on retention of full metal crowns: comparative study.

INTRODUCTION: The aim of this study was to evaluate the effects of eugenol-free temporary cement's remnants on the retentive strength of full metal crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. MATERIALS AND METHODS: Forty complete standardized Ni-Cr crowns in four groups were cemented by two types of permanent cements: zinc phosphate cement and resin cement (Maxcem). In the two groups before permanent cementation of crowns, temporary acrylic crowns were cemented by eugenol-free temporary cement. Crowns' retention was evaluated by Universal testing machine. All data were analyzed by means of one-way ANOVA test in SPSS software version 11.5 (α=0.05). RESULTS: There was no significant difference in groups with prior using eugenol-free temporary cement and groups with just using two permanents cement (p-value≥0.05). DISCUSSION: The application of temporary cement before permanent cementation of full metal crowns does not have any adverse effect on retention of full metal crowns, when temporary cements are removed properly.

Effect of base metal alloys recasting on marginal integrity of castable crowns.

INTRODUCTION: Base metals have a wide use in casting methods. Sometimes they are reused in laboratories which may have an adverse effect on the restoration marginal integrity. This study aimed to investigate the effect of recasting of alloys on marginal integrity of restorations. MATERIALS AND METHODS: Models with two types of finishing lines shoulder bevel 45° and shoulder 135° were produced and 15 wax copings were formed on each one of them. Each group containing 15 copings was divided into three subgroups A, B and C. Group A was casted with 100% new alloy, group B with 50% new and 50% recasted alloy and group C with 100% recasted alloy. Obtained metal copings were placed on dies and marginal gap size between restoration margin and the dies finishing line was measured using metric microscope and Moticam camera in four points, buccal, lingual, mesial and distal. RESULTS: A significant difference in mean marginal gap size exists among three types of alloys used (p-value = 0.036). A significant difference is observed between mean marginal gap size of two types of finishing lines for different alloys (p-value = 0.001). CONCLUSION: Using 100% recasted alloy is not recommended for any of the two types of finishing lines.