Dental Research Journal
Volume:18 Issue: 11, Dec 2021

The aim of this study was to evaluate the retention of implant‑supported overdentures with different attachment systems.

In this in vitro study edentulous model with 2 Straumann implant in symphyseal region was used to make an overdenture with different attachment systems. (Dolder bar with 1 and 3 metal clips, Hader bar with 1 and 3 plastic clips, ball on bar with 2 and 4 plastic caps, Locator, Rhein plastic caps and Eleptical matrix). Retention values were recorded by universal testing machine with a cross speed of 50.8 mm/min in vertical, posteroanterior, and lateral direction. Repeated measure ANOVA and Duncan tests were used for the data analysis (α =0.05).

There was a statistically significant difference between the retention values of studied attachments in different dislodgment directions (P < 0.05).The highest and lowest retention were recorded for 4 balls on bar (56.71 N) and Rhein pink caps(27.89 N) in the vertical direction.Three metal clips (61.43 N) and Rhein pink cap (24.77 had the highest and lowest retention force in the posteroanterior direction. In the lateral direction, 4 balls on bar (62.68 N) and 1 plastic clip (32.27 N) showed the highest and lowest retention, respectively.

If the higher retention force has been considered for implant‑supported overdenture attachment selection, the clinician can use splinted bar or ball on bar superstructure.

Ossifying fibromas (OFs) are benign, well‑demarcated lesions in the craniofacial region, particularly in the jaws, with clinical, radiographic, and histopathological similarities to other lesions, which make their diagnosis challenging. Herein, we report a case of a fibro‑osseous lesion in the anterior maxilla of a 13‑year‑old boy, consisting of an intraosseous and an extra‑osseous part, which created a diagnostic dilemma.

Dentists might face various artifacts (such as triangular‑shaped radiolucencies[TSRs]) during the assessment of radiographs and should be able to differentiate them from caries to avoid unnecessary treatments.

In this cross‑sectional study, 109 maxillary second primary molars were evaluated in cooperative children aged 4–9 years, who had distal caries in their maxillary first primary molars. First,TSRs were recorded on periapical radiographs of each maxillary second primary molar’s proximal surface.Then, after excavating distal caries in the adjacent teeth “D,” a pedodontist examined the mesial surfaces of teeth “E.” Chi‑square test was used to compare the distribution of caries in different variables, and the kappa coefficient was applied to evaluate clinical and radiographic agreements.A P < 0.05 was considered statistically significant.

Forty‑four cases were found to be carious both clinically and radiographically, and 54 cases were noncarious by both methods, while for 11 cases, the diagnosis was controversial. No statistically significant difference was found between radiographic and clinical caries detection methods in children whose periapical radiographs contained TSRs, and most of the subjects had similar diagnoses. Value of caries detection sensitivity, specificity, positive predictive value, and negative predictive value in TSRs was 88%, 92%, 90%, and 90%, respectively.

Considering high radiographic sensitivity for caries detection inTSRs,clinicians should be more cautious about them being carious or not, and both radiographic and clinical examinations are necessary. Further, to avoid misinterpretation in radiographs, additional education is necessary for young dentists.

It is difficult to perform dental procedures in autistic children, and parental involvement is necessary for successful hospital dental services.Therefore, in order to promote oral health in autistic children, this study was aimed to explore the knowledge, attitude, and performance of autistic children’s parents with respect to hospital dentistry.

This cross‑sectional study was conducted with the parents of 100 autistic children aged 2–6 years selected from among the children of Isfahan autism treatment centers. A self‑administered questionnaire, including parental demographic information and 22 items on the assessment of knowledge, attitude, and performance of autistic children’s parents regarding hospital dental procedures under general anesthesia, was completed by 100 parents. P <0.05 was considered statistically significant. Data were analyzed by SPSS software using Chi‑square test.

A total of 100 parents of autistic children, with an average age of 37.4 ± 6.1 years, were recruited in this study.The results showed that 56%, 50%, and 3% of parents had poor knowledge about dental hospital services, dental complications, and hospital dentistry rules, respectively. Further, 51% of parents believed that general anesthesia was dangerous to their children. In addition, 69% of children had little or no cooperation with the dentist.There was also a significant relationship between the knowledge, attitude, and performance of autistic children’s parents regarding hospital dentistry and the parents’ age and sex.

This study showed that autistic children’s parents had poor knowledge, attitude, and performance with respect to hospital dentistry.

This study aimed to assess the effect of different whitening toothpastes containing activated charcoal, abrasive particles or hydrogen peroxide on the color of aged microhybrid composite.

In this in vitro, experimental study, 45 composite discs (2 mm × 7 mm) were fabricated of a microhybrid composite.They underwent accelerated artificial aging for 300 h, corresponding to 1 year of clinical service. The composites were then randomly divided into five groups (n = 9). One group served as the control and underwent tooth brushing with distilled water. The remaining four groups underwent tooth brushing with Colgate Total whitening (Gt), Colgate Optic White (Go), Perfect White Black (Gp) and Bencer (Gb) toothpastes in a brushing machine The International Commission on Illumination values (Lm, am, bm) were determined using a spectrophotometer. Color change (ΔE) calculated based on this formula: ΔEm= ([ΔLm] 2 + [Δam] 2 + [Δbm] 2)½. The differences were defined by ΔE1 (after aging‑baseline),ΔE2 (after brushing‑after aging) and ΔE3 (after brushing‑base line). ΔE1 were evaluated to ensure that color mismatch had occurred (∆E1 > 5.5). Difference in (L, a, b) parameters after aging and after tooth brushing in each group, color parameter changes (ΔL2, Δa2, Δb2, ΔL3, Δa3, Δb3) and ΔE2 and ΔE3 were analyzed and compared usingWilcoxon test and independent sample median test at P = 0.05 level of significance.

The color parameter changes, ΔE3 and ∆ E2 were not significantly different among the five groups (P > 0.05). In Gp and Gb charcoal a*, b*, and L* after tooth brushing (P < 0.05). In Colgate Optic group, the a* parameter significantly decreased while the L* parameter significantly increased (P < 0.05).

The results showed that there is no significant difference in the color change of Spectrum composite following tooth brushing with different whitening toothpastes for two weeks. It should be noted that ∆ E3 reached to <3.3 only in charcoal whitening toothpastes.

Cleaning and shaping of root canals are essential steps for the success of endodontic therapy. This study compared two types of rotary files in oval‑shaped root canals: XP‑endo shaper (FKG, La Chaux‑de‑ Fonds, Switzerland) and Mtwo (VDW, Germany, Munich) with regard to cleaning ability and canal preparation. Mtwo is a system of nickel–titanium files with S‑shaped cross‑sectional design and XP‑endo shaper can change its shape according to the temperature.

This in vitro study was performed on 16 pairs of freshly extracted contralateral mandibular premolars with a single oval‑shaped canal that were selected and divided into two groups according to the root canal instrumentation technique: XP‑endo shaper and Mtwo. Then, each root cut into three coronal, middle and apical sections and processed for histologic evaluation of canal wall planning and the presence of debris. Sections were evaluated by using AutoCAD 2017 software. Statistical analysis was used to compare between both the groups using repeated measures multivariate analysis of variance with Bonferroni correction for post hoc comparison and independent sample t‑tests.The level of statistical significance was set at P < 0.05.

With a statistically significant difference in the middle third, untouched area and area with debris in XP‑endo shaper group were smaller (respectively P = 0.013 and P = 0.011). Despite the percentage difference between groups, there was not a statistically significant difference in other sections.

Statistically in the middle section of the oval‑shaped canals, the XP‑endo shaper performs better than the Mtwo rotary files.

The present study aimed to evaluate the stress distribution of porous tantalum implant and titanium solid implant assisted overdenture (IAO) in mandibular bone by utilizing three‑dimensional (3D) finite element (FE) analysis.

In this FE study, an existing cone‑beam volumetric tomography scan of a patient without any maxillofacial anomaly with an available acceptable IAO for mandible was used to attain the compartments of a completely edentulous mandible. Zimmer trabecular implants and locator attachment systems were selected as the case group (Model B), and Zimmer Screw‑Vent implants and locator attachment system were chosen for the control (Model A), as overdenture attachments in the present study. The mandibular overdenture was scanned and digitized as a FE model. Two 3D FE models were designed as edentulous lower jaws, each with four implants in the anterior section of the mandible. Three forms of loads were directed to the IAO in each model: Vertical loads on the left first molar vertical molar (VM). Vertical loads on the lower incisors (VI). Inclined force buccolingually applied at left first molar (IM).

Under all loading conditions, the maximum strain values in peri‑implant bone in Model A were less than Model B. Under VI, the greatest stress value around abutments in both models was about 2–3 times higher than the other loads. Under VM and IM loads, no significant difference was observed between models.

Using trabecular metal implants instead of solid implants reduces strain values around both cortical and trabecular bone.

This study aimed to assess and compare the type of dental procedures performed under general anesthesia for healthy and disabled children.

This descriptive, cross‑sectional study evaluated 361 dental records of children who received dental treatments under general anesthesia in the operating room of Torabinejad Research Center during 2011–2013. Patients with mental or physical disability were categorized as disabled.The age and gender of patients, number of treated teeth, duration of general anesthesia, type of tooth, and type of dental treatment such as extraction, pulp therapy, placement of stainless steel crowns, composite restoration, preventive resin restoration (PRR), fissure sealant treatment, and fluoride therapy were separately recorded for the healthy group and patients with disability. Data were analyzed using one‑way ANOVA, and independent sample t‑test at P < 0.05 level of significance.

Of 361 patients, 263 patients were healthy and 102 patients had disability. Of all disabled children, 48% had physical and 52% had mental disability. Among patients with physical disability, allergy (40%), followed by cardiovascular diseases (26%) were the most common. Mental retardation (54%) followed by cerebral palsy (10%) were the most common mental disabilities. Number of extracted teeth was significantly higher in disabled children (P = 0.006). Furthermore, disabled children received significantly lower PRR (P = 0.015), fissure sealant treatment (P = 0.003), fluoride therapy (P = 0.002), and pulp therapy (P < 0.001) compared with healthy children.

Tooth extraction has a higher frequency in disabled children; while, attempts are made to preserve the teeth as much as possible in healthy children.

Antimicrobial nanoparticles (NPs) have various applications in different fields of dentistry.The purpose of incorporating NPs into orthodontic adhesives is to inhibit the cariogenic bacteria and reduce decalcifications around bonded orthodontic brackets. However, they may affect the physical and mechanical properties of adhesive such as shear bond strength (SBS).This review was done to answer the question whether the incorporation of antimicrobial NPs into orthodontic adhesives changes the SBS.

An electronic search was performed with keywords such as adhesives AND nanoparticles AND orthodontics AND shear strength.After screening and applying eligibility criteria, 18 relevant studies were included.

The pooled data suggest that except for 10 wt% of various NPs incorporation, there is no significant difference in SBS between control conventional adhesives and experimental modified ones with tested concentrations.

The SBS of orthodontic adhesives containing up to 5% NPs is in clinical acceptable range. However, generalizing the results to in vivo situation may be problematic and further studies are required.