Publications by authors named "Alireza Hashemi Ashtiani"

Systemic sclerosis (SS) is a debilitating disease that affects oral and any other tissues including skin, bone, blood vessels, and the connective tissues by excessive collagen accumulation. It is a difficult case for oral rehabilitation, let alone dental implantation. In this regard, only few studies have been conducted.

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Introduction: Orthodontic clear aligners and retainers have numerous advantages that is making them ever increasingly popular. However, they might, similar to any other oral appliance, contribute to biofilm formation and finally dental caries or white spot lesions or gingival inflammations. The literature on biofilm formation on orthodontic clear appliances is very scarce and limited to a few microorganisms and materials.

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No study has examined the simultaneous effect of facial forms, midline deviations and midline angulations on facial beauty. Therefore, this comprehensive study aimed to evaluate these and many other hypotheses. This psychometric study was performed on 15,042 observations.

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Background: The 3D position of the mental foramen (MF) is of significant clinical value in dental implantology and mandibular surgeries or in local anesthesia. Despite its importance, it is not clearly known how the position of MF can alter in different individuals, since the literature on the associations between the MF position with vertical growth patterns is non-existent and those on links between the MF position and skeletal malocclusions are scarce. Therefore, we aimed to investigate these, for the first time, on cone-beam computed tomographies (CBCTs).

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Background: An ever-increasing demand is seen for clear aligners and transparent vacuum-formed retainers. They are esthetic and convenient. However, the biomaterials used in these appliances might pose biological safety and biocompatibility threats in terms of their bisphenol-A (BPA) release, cytotoxicity, adverse effects, and estrogenic effects.

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Objectives: The jaw angle plays an important role in facial beauty. Therefore, this study is aimed at comparatively determining the range of most attractive female intergonial widths and gonial heights on Perceptometric frontal-view and three-quarter-view images, from the perspective of orthodontists, oral maxillofacial (OMF) surgeons, and laypeople of different ages and sexes.

Methods: This prospective multivariate Perceptometric study was performed on 4191 esthetic scores given by 127 individuals to 33 Perceptometric face images.

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Article Synopsis
  • * A panoramic radiograph and CBCT revealed multiple impacted supernumerary teeth located in both the maxilla and mandible, with no accompanying symptoms or oral abnormalities.
  • * All but one of the supernumerary teeth were extracted prior to orthodontic treatment, and the patient experienced no complications, emphasizing the importance of radiographic screenings to identify hidden dental issues.
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Statement Of Problem: How multiple firing cycles may affect the oxide layer and, consequently, the shear bond strength of metal-ceramic restorations is unclear.

Purpose: The purpose of this in vitro study was to determine the effect of multiple firings on the shear bond strength of porcelain to cobalt-chromium (Co-Cr) alloy.

Material And Methods: Forty cylinders (Ø6.

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Background And Aims: The replacement of teeth with osseointegrated implants is one of the significant advances in the field of restorative dentistry. The time interval between tooth extraction and the implant can be very short or long. This systematic review and meta-analysis aimed to collect and evaluate articles related to determining the effect of instant loading of dental implants are placed in the fresh socket initial stability on the clinical success of the implant compared to delay loading dental implants.

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Article Synopsis
  • * It involved 20 human premolars chewing against samples of both ceramics in a simulator, measuring enamel wear before and after.
  • * Results showed that the feldspathic porcelain caused significantly more enamel wear (377.294 μ) compared to the polymer-infiltrated ceramic (101.755 μ), indicating that the latter is gentler on natural teeth.
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Article Synopsis
  • The study aimed to assess how different surface treatments and types of zirconia affect the shear bond strength (SBS) between zirconia cores and veneering porcelain.
  • Eighty zirconia disks (white and colored) were used, treated with various mechanical methods, and tested for SBS, showing that surface treatment techniques significantly impacted bond strength.
  • While the type of zirconia did not affect SBS, grinding treatment reduced the bond strength in white zirconia compared to other treatments.
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