Displaying publications 1 - 20 of 58 in total

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  1. Yacob N, Ahmad NA, Safii SH, Yunus N, Abdul Razak F
    J Prosthet Dent, 2023 Jul;130(1):131.e1-131.e7.
    PMID: 37210224 DOI: 10.1016/j.prosdent.2023.04.017
    STATEMENT OF PROBLEM: How the build orientation of a 3-dimensionally (3D) printed denture affects microbial adhesion is unclear.

    PURPOSE: The purpose of this in vitro study was to compare the adherence of Streptococcus spp. and Candida spp. on 3D-printed denture bases prepared at different build orientations with conventional heat-polymerized resin.

    MATERIAL AND METHODS: Resin specimens (n=5) with standardized 28.3 mm2 surface area were 3D printed at 0 and 60 degrees, and heat-polymerized (3DP-0, 3DP-60, and HP, respectively). The specimens were placed in a Nordini artificial mouth (NAM) model and exposed to 2 mL of clarified whole saliva to create a pellicle-coated substratum. Suspensions of Streptococcus mitis and Streptococcus sanguinis, Candida albicans and Candida glabrata, and a mixed species, each at 108 cfu/mL were pumped separately into the model for 24 hours to promote microbial adhesion. The resin specimens were then removed, placed in fresh media, and sonicated to dislodge attached microbes. Each suspension (100 μL) was aliquoted and spread on agar plates for colony counting. The resin specimens were also examined under a scanning electron microscope. The interaction between types of specimen and groups of microbes was examined with 2-way ANOVA and then further analysis with Tukey honest significant test and Kruskal-Wallis post hoc tests (α=.05).

    RESULTS: A significant interaction was observed between the 3DP-0, 3DP-60, and HP specimen types and the groups of microbes adhering to the corresponding denture resin specimens (P

  2. Ahmed N, Khalid S, Vohra F, Halim MS, Al-Saleh S, Tulbah HI, et al.
    J Prosthet Dent, 2024 Feb;131(2):187-196.
    PMID: 35277267 DOI: 10.1016/j.prosdent.2021.11.035
    STATEMENT OF PROBLEM: The recurrent esthetic dental (RED) proportion has been a benchmark for the rehabilitation of the maxillary anterior teeth of North American patients. While it has been evaluated in other populations, the global application of RED proportions in the rehabilitation of maxillary anterior teeth is unclear.

    PURPOSE: The purpose of this systematic review was to examine the existing evidence on dental proportion to evaluate the existence of RED proportions in the esthetic smile in different geographic regions.

    MATERIAL AND METHODS: A systematic search was conducted by reviewing different databases. The focused question was "Does RED proportion exist in esthetically pleasing smiles in different populations around the world?" The search included articles with a combination of MeSH keywords based on dental proportion from January 2000 to July 2020. The titles and abstracts were identified by using a search protocol. Full text of the articles was independently evaluated. The systematic review was modified to summarize the relevant data. The general characteristics, outcomes, and quality of studies were reviewed and analyzed systematically.

    RESULTS: Seventeen studies were selected from the reviewed articles. Three studies were conducted in Europe, 10 in South Asia, and 4 in Western Asia. Eleven studies found that the mean perceived ratio of anterior teeth was not constant when progressing distally. Five studies reported that the ratio was constant in a small percentage of their populations, and 1 suggested that the ratio was constant if it remains between 60% and 80%. The central-to-LI and Ca-to-LI proportion values were not constant. Overall, the Ca-to-LI proportion values were higher than the central-to-LI proportions.

    CONCLUSIONS: RED proportions were not found in the successive widths of maxillary anterior teeth among the reviewed data from different geographic regions. RED proportions are not the only standard for restoring esthetic smiles worldwide, and anterior tooth proportions differ among populations based on their race and ethnicity.

  3. Rahman AM, Jamayet NB, Nizami MMUI, Johari Y, Husein A, Alam MK
    J Prosthet Dent, 2021 Jan 17.
    PMID: 33472753 DOI: 10.1016/j.prosdent.2020.07.026
    STATEMENT OF PROBLEM: The climate of tropical Southeast Asia includes high humidity and ultraviolet radiation that reduce the lifespan of silicone prostheses by inducing changes in their mechanical properties and color stability. Studies on the surface roughness (SR) and mechanical properties of different silicone elastomers (SEs) subjected to the natural tropical weather of Southeast Asia are lacking.

    PURPOSE: The purpose of this in vitro study was to evaluate the SR, tensile strength (TS), and percentage elongation (% E) of different SEs subjected to outdoor weathering in the Malaysian climate.

    MATERIAL AND METHODS: Type-II dumbbell-shaped specimens (N-120) (nonweathered=15, weathered=15) were made from 3 room-temperature vulcanized (A-2000, A-2006, and A-103) and 1 heat-temperature vulcanized (M-511) silicone (Factor II). For 6 months, weathered specimens were subjected to outdoor weathering inside a custom exposure rack. Simultaneously, the nonweathered specimens were kept in a dehumidifier. Subsequently, the SR was measured with a profilometer; TS and % E were measured by using a universal testing machine. Two-way ANOVA was used to compare the means of the tested properties of the nonweathered and weathered specimens, and pairwise comparison was carried out between the silicones (α=.05).

    RESULTS: After outdoor weathering, the SR, TS, and % E were adversely affected by weathering in the Malaysian environment. Among the silicone materials, A-2000 showed the least TS changes (2.51 MPa), while A-2006 demonstrated significant changes in percentage elongation after outdoor weathering (266.5%). M-511 exhibited the highest mean value (2.50 μm) for SR changes. In addition, A-103 SE showed statistically significant differences in most pairwise comparisons for all 3 dependent variables.

    CONCLUSIONS: Based on the evaluation of mechanical properties, A-103 can be suggested as a suitable silicone for maxillofacial prostheses fabricated for tropical climates. However, A-2000 can be a suitable alternative, although significant changes to surface roughness were detected after outdoor weathering.

  4. Farook TH, Abdullah JY, Jamayet NB, Alam MK
    J Prosthet Dent, 2021 Feb 15.
    PMID: 33602541 DOI: 10.1016/j.prosdent.2020.07.039
    STATEMENT OF PROBLEM: Computer-aided design (CAD) of maxillofacial prostheses is a hardware-intensive process. The greater the mesh detail is, the more processing power is required from the computer. A reduction in mesh quality has been shown to reduce workload on computers, yet no reference value of reduction is present for intraoral prostheses that can be applied during the design.

    PURPOSE: The purpose of this simulation study was to establish a reference percentage value that can be used to effectively reduce the size and polygons of the 3D mesh without drastically affecting the dimensions of the prosthesis itself.

    MATERIAL AND METHODS: Fifteen different maxillary palatal defects were simulated on a dental cast and scanned to create 3D casts. Digital bulbs were fabricated from the casts. Conventional bulbs for the defects were fabricated, scanned, and compared with the digital bulb to serve as a control. The polygon parameters of digital bulbs were then reduced by different percentages (75%, 50%, 25%, 10%, 5%, and 1% of the original mesh) which created a total of 105 meshes across 7 mesh groups. The reduced mesh files were compared individually with the original design in an open-source point cloud comparison software program. The parameters of comparison used in this study were Hausdorff distance (HD), Dice similarity coefficient (DSC), and volume.

    RESULTS: The reduction in file size was directly proportional to the amount of mesh reduction. There were minute yet insignificant differences in volume (P>.05) across all mesh groups, with significant differences (P

  5. Chong WX, Lai YX, Choudhury M, Amalraj FD
    J Prosthet Dent, 2022 Nov;128(5):1114-1120.
    PMID: 33685653 DOI: 10.1016/j.prosdent.2021.01.010
    STATEMENT OF PROBLEM: The presence of biofilms on maxillofacial silicone increases the risk of infections and reduces durability. Whether silver nanoparticles (AgNPs) with potent antimicrobial effects help reduce biofilm formation is unclear.

    PURPOSE: The purpose of this in vitro study was to assess the antimicrobial effect of sub 10-nm AgNPs in maxillofacial silicone against Staphylococcus aureus, Candida albicans, and mixed species biofilms containing both and to test the effectiveness of different AgNP concentrations against all 3 biofilms in vitro.

    MATERIAL AND METHODS: Silicone disks (M511; Technovent Ltd) containing 0.0% (control), 0.1%, and 0.5% AgNPs were fabricated and treated with S. aureus, C. albicans, and mixed species strains of both in 24-well culture plates containing appropriate media. Each well received a 0.1-mL aliquot of the standardized suspension of microorganisms. The plates were incubated for 21 consecutive days, and colony-forming units per milliliter (CFU/mL) were measured on the first, third, fifth, seventh, fifteenth, and twenty-first day with the Miles and Misra method. Data were analyzed by 2-way ANOVA and the paired t test to evaluate the relationship between AgNP concentration, microbial strain, and time (α=.05). Mean CFU/mL differences for each time and for each biofilm category were assessed by repeated measure ANOVA.

    RESULTS: AgNPs decreased the mean CFU/mL in both concentrations compared with the control. The 0.1% concentration showed sustained efficacy throughout the test, while the 0.5% concentration had high efficacy initially with a gradual decrease. However, the results were inconsistent for the mixed biofilm. The paired sample t test at day 3 and 15 and day 3 and 21 showed statistically significantly different results (P

  6. Sulong MZ, Aziz RA
    J Prosthet Dent, 1990 Mar;63(3):342-9.
    PMID: 2407832
    This is a review of the literature concerning wear related to the following materials used in dentistry: dental amalgam, composite resins, and glass-ionomer cements, as well as natural tooth substance. Discussions are included on both in vivo and in vitro studies in which various methods were used to help determine wear resistance.
  7. Sivakumar I, Arunachalam S, Choudhary S, Buzayan MM
    J Prosthet Dent, 2021 Jun;125(6):862-869.
    PMID: 32694022 DOI: 10.1016/j.prosdent.2020.04.001
    STATEMENT OF PROBLEM: Immunosuppression and coinfections associated with human immunodeficiency virus (HIV) infection pose a relative contraindication for dental implant therapy. However, although implants have been placed in patients with HIV with reasonable success, how HIV infection affects their survival is unclear.

    PURPOSE: The purpose of this systematic review of the literature and meta-analysis was to analyze the data on the survival of dental implants in patients with HIV.

    MATERIAL AND METHODS: A search for relevant articles published up to November 2019 was performed in PubMed/Medline and Cochrane databases, Clinicaltrials.gov, and Google Scholar. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted for the conduct of the systematic review. The most pertinent data were extracted and pooled for qualitative and quantitative analyses with 95% confidence intervals. Heterogeneity was analyzed by using I-squared statistics.

    RESULTS: A total of 8 studies involving 411 individuals with HIV and 1109 implants were included in the meta-analysis. The mean follow-up period was 2.8 years. A pooled estimate of 95% of implant survival rate with 95% confidence interval(92% to 96%) was noted. Heterogeneity across the 8 studies was found to be 41% with moderate true variability.

    CONCLUSIONS: This systematic review demonstrated that HIV infection does not pose a serious threat to implant survival on short-term evaluation, but the evidence is of low quality.

  8. Ahmad R, Morgano SM, Wu BM, Giordano RA
    J Prosthet Dent, 2005 Nov;94(5):421-9.
    PMID: 16275301
    Many studies on the strengthening effects of grinding and polishing, as well as heat treatment on ceramics, are not well standardized or use commercially available industrial polishing systems. The reported effectiveness of these strengthening mechanisms on ceramics may not be applicable to clinical dentistry.
  9. Yunus N, Abdullah H, Hanapiah F
    J Prosthet Dent, 2001 Jun;85(6):540-3.
    PMID: 11404753
    This article describes the occlusal rehabilitation of a partially edentulous patient who did not want a removable partial denture. Implants and extensive fixed restorations were used to restore posterior support and treat severely worn dentition, respectively. The treatment offered the patient a functional and esthetic result.
  10. Razak AA, Harrison A
    J Prosthet Dent, 1997 Apr;77(4):353-8.
    PMID: 9104710
    Dimensional accuracy of a composite inlay restoration is important to ensure an accurate fit and to minimize cementation stresses.
  11. Ahmed N, Halim MS, Khalid S, Ghani ZA, Jamayet NB
    J Prosthet Dent, 2021 Jul 31.
    PMID: 34340826 DOI: 10.1016/j.prosdent.2021.06.015
    STATEMENT OF PROBLEM: The color and form of teeth are 2 of the 3 main determinants of success in an esthetic restoration; the third is dental proportion. A recent systematic review of the literature devoted to the evaluation of dental proportion is lacking.

    PURPOSE: The purpose of this systematic review was to investigate the quality and outcome of studies into maxillary anterior tooth proportion and to determine whether dental proportion ratios based on different geographic regions are appropriate.

    MATERIAL AND METHODS: An electronic search was conducted using PubMed, MEDLINE, Google Scholar, Embase, Scopus, Cochrane Library, Web of Science, and Science Direct databases. English-language articles reporting with the specific combination of medical subject heading (MeSH) key words were analyzed by 2 investigators. The titles, full text, and abstracts were scanned by investigators independently to identify articles that fulfilled the inclusion criteria. The general characteristics, outcomes, and quality of each study were reviewed and analyzed systematically.

    RESULTS: The search plan resulted in a total of 73 articles until September 2020; of which, 16 articles fulfilling the inclusion criteria were selected. The geographic distribution of the selected article revealed 12 articles from Asia, 2 from Continental Europe, and 2 from the United Kingdom. Golden percentage values of 25%, 15%, and 10% for central, lateral incisor, and canine teeth were not found. The mean predicted dental percentage was either larger or smaller than the successive widths of maxillary natural anterior teeth.

    CONCLUSIONS: The golden percentage could not be used to formulate a smile design. Rather, the dental ratios should be set on a racial and ethnic basis for a population.

  12. Vohra F, Al-Kheraif AA, Ab Ghani SM, Abu Hassan MI, Alnassar T, Javed F
    J Prosthet Dent, 2015 Sep;114(3):351-7.
    PMID: 26047803 DOI: 10.1016/j.prosdent.2015.03.016
    STATEMENT OF PROBLEM: Zirconia implants have been used for oral rehabilitation; however, evidence of their ability to maintain crestal bone and periimplant soft tissue health is not clear.

    PURPOSE: The purpose of this systematic review was to evaluate crestal bone loss (CBL) around zirconia dental implants and clinical periimplant inflammatory parameters.

    MATERIAL AND METHODS: The focus question addressed was, "Do zirconia implants maintain crestal bone levels and periimplant soft tissue health?" Databases were searched for articles from 1977 through September 2014 with different combinations of the following MeSH terms: "dental implants," "zirconium," "alveolar bone loss," "periodontal attachment loss," "periodontal pocket," "periodontal index." Letters to the editor, case reports, commentaries, review articles, and articles published in languages other than English were excluded.

    RESULTS: Thirteen clinical studies were included. In 8 of the studies, the CBL around zirconia implants was comparable between baseline and follow-up. In the other 5 studies, the CBL around zirconia implants was significantly higher at follow-up. Among the studies that used titanium implants as controls, 2 studies showed significantly higher CBL around zirconia implants, and in 1 study, the CBL around zirconia and titanium implants was comparable. The reported implant survival rates for zirconia implants ranged between 67.6% and 100%. Eleven studies selectively reported the periimplant inflammatory parameters.

    CONCLUSIONS: Because of the variations in study design and methodology, it was difficult to reach a consensus regarding the efficacy of zirconia implants in maintaining crestal bone levels and periimplant soft tissue health.

  13. Mustafa AA, Matinlinna JP, Saidin S, Kadir MR
    J Prosthet Dent, 2014 Dec;112(6):1498-506.
    PMID: 24993375 DOI: 10.1016/j.prosdent.2014.05.011
    STATEMENT OF PROBLEM: The inconsistency of dentin bonding affects retention and microleakage.

    PURPOSE: The purpose of this laboratory and finite element analysis study was to investigate the effects on the formation of a hybrid layer of an experimental silane coupling agent containing primer solutions composed of different percentages of hydroxyethyl methacrylate.

    MATERIAL AND METHODS: A total of 125 sound human premolars were restored in vitro. Simple class I cavities were formed on each tooth, followed by the application of different compositions of experimental silane primers (0%, 5%, 25%, and 50% of hydroxyethyl methacrylate), bonding agents, and dental composite resins. Bond strength tests and scanning electron microscopy analyses were performed. The laboratory experimental results were validated with finite element analysis to determine the pattern of stress distribution. Simulations were conducted by placing the restorative composite resin in a premolar tooth by imitating simple class I cavities. The laboratory and finite element analysis data were significantly different from each other, as determined by 1-way ANOVA. A post hoc analysis was conducted on the bond strength data to further clarify the effects of silane primers.

    RESULTS: The strongest bond of hybrid layer (16.96 MPa) was found in the primer with 25% hydroxyethyl methacrylate, suggesting a barely visible hybrid layer barrier. The control specimens without the application of the primer and the primer specimens with no hydroxyethyl methacrylate exhibited the lowest strength values (8.30 MPa and 11.78 MPa) with intermittent and low visibility of the hybrid layer. These results were supported by finite element analysis that suggested an evenly distributed stress on the model with 25% hydroxyethyl methacrylate.

    CONCLUSIONS: Different compositions of experimental silane primers affected the formation of the hybrid layer and its resulting bond strength.

  14. Chadda H, Naveen SV, Mohan S, Satapathy BK, Ray AR, Kamarul T
    J Prosthet Dent, 2016 Jul;116(1):129-35.
    PMID: 26873771 DOI: 10.1016/j.prosdent.2015.12.013
    STATEMENT OF PROBLEM: Although the physical and mechanical properties of hydroxyapatite-filled dental restorative composite resins have been examined, the biocompatibility of these materials has not been studied in detail.

    PURPOSE: The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination.

    MATERIAL AND METHODS: Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software.

    RESULTS: Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis.

    CONCLUSIONS: The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials.

  15. Farook TH, Rashid F, Jamayet NB, Abdullah JY, Dudley J, Khursheed Alam M
    J Prosthet Dent, 2022 Oct;128(4):830-836.
    PMID: 33642077 DOI: 10.1016/j.prosdent.2020.12.041
    STATEMENT OF PROBLEM: The anatomic complexity of the ear challenges conventional maxillofacial prosthetic rehabilitation. The introduction of specialized scanning hardware integrated into computer-aided design and computer-aided manufacturing (CAD-CAM) workflows has mitigated these challenges. Currently, the scanning hardware required for digital data acquisition is expensive and not readily available for prosthodontists in developing regions.

    PURPOSE: The purpose of this virtual analysis study was to compare the accuracy and precision of 3-dimensional (3D) ear models generated by scanning gypsum casts with a smartphone camera and a desktop laser scanner.

    MATERIAL AND METHODS: Six ear casts were fabricated from green dental gypsum and scanned with a laser scanner. The resultant 3D models were exported as standard tessellation language (STL) files. A stereophotogrammetry system was fabricated by using a motorized turntable and an automated microcontroller photograph capturing interface. A total of 48 images were captured from 2 angles on the arc (20 degrees and 40 degrees from the base of the turntable) with an image overlap of 15 degrees, controlled by a stepper motor. Ear 1 was placed on the turntable and captured 5 times with smartphone 1 and tested for precision. Then, ears 1 to 6 were scanned once with a laser scanner and with smartphones 1 and 2. The images were converted into 3D casts and compared for accuracy against their laser scanned counterparts for surface area, volume, interpoint mismatches, and spatial overlap. Acceptability thresholds were set at <0.5 mm for interpoint mismatches and >0.70 for spatial overlap.

    RESULTS: The test for smartphone precision in comparison with that of the laser scanner showed a difference in surface area of 774.22 ±295.27 mm2 (6.9% less area) and in volume of 4228.60 ±2276.89 mm3 (13.4% more volume). Both acceptability thresholds were also met. The test for accuracy among smartphones 1, 2, and the laser scanner showed no statistically significant differences (P>.05) in all 4 parameters among the groups while also meeting both acceptability thresholds.

    CONCLUSIONS: Smartphone cameras used to capture 48 overlapping gypsum cast ear images in a controlled environment generated 3D models parametrically similar to those produced by standard laser scanners.

  16. Tan WY, Ng JZL, Ajit Bapat R, Vijaykumar Chaubal T, Kishor Kanneppedy S
    J Prosthet Dent, 2021 May;125(5):766.e1-766.e8.
    PMID: 33752904 DOI: 10.1016/j.prosdent.2021.02.018
    STATEMENT OF PROBLEM: Lingual plate perforation can be life-threatening when vital structures are damaged during implant placement. Knowledge of the anatomy of lingual concavities is imperative for safe implant surgery.

    PURPOSE: The purpose of this clinical study was to determine the prevalence of type of posterior mandibular ridge morphology in a Malaysian population and to evaluate the buccolingual width of the alveolar ridge (Wb and Wc); alveolar ridge height (Vcb); and concavity angle, length, and depth for both left and right first and second molars in different age groups and sexes by using cone beam computed tomography (CBCT).

    MATERIAL AND METHODS: Bilateral posterior mandibular lingual concavities at the first and second molars were retrospectively studied in cross-sectional views of 150 CBCT scans (n=600 sites evaluated). The sample size was calculated at a power of 80%, confidence interval of 95%, and margin of error of .05. The buccolingual width from the base and crest of the ridge and the ridge height were measured to determine the type of ridge. For the U-shaped ridge, the concavity angle, length, and depth were assessed. The independent t test was used to compare mean values of CBCT measurements between sexes and tooth type, while the ANOVA and Pearson chi-squared test were used to determine the correlations with age groups and types of ridge morphology, respectively. To compare the left and right readings for first and second molars in the same patient, the paired t test was performed (α=.05 for all tests).

    RESULTS: The Pearson correlation showed a strong agreement between the 2 examiners with an interobserver reliability of 87.3%. Significant difference was noted in all dimensional measurements when comparing right and left first and second molars (P

  17. Aggarwal H, Kumar P, Eachempati P, Krishanappa SK
    J Prosthet Dent, 2015 Sep;114(3):456-7.
    PMID: 26047802 DOI: 10.1016/j.prosdent.2015.04.010
    This article describes a cost-effective, expedient, and time-saving technique for surface texturing a facial prosthesis with fine sand mixed in resin adhesive glue.
  18. Patil PG, Lim HF
    J Prosthet Dent, 2023 Jul;130(1):14-18.
    PMID: 34774303 DOI: 10.1016/j.prosdent.2021.08.005
    Fabricating a new crown to retrofit with an existing removable partial denture (RPD) is a complex procedure for both clinician and dental laboratory technician. The presented technique facilitates the fabrication and retrofitting of a metal-ceramic crown onto the principal abutment of the existing RPD by using 2-step intraoral scanning (with and without the RPD in place) and 2 different 3-dimensionally printed casts. The technique enables the dental laboratory technician to precisely reproduce the retentive areas, guiding planes, and rest seats on the retrofitted crown.
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