PURPOSE: The purpose of this clinical study was to formulate a custom-made, 2-color chewing gum for the mixing ability test and to develop an image-processing method for color mixing analysis.

MATERIAL AND METHODS: Specimens of red-green (RG) chewing gum were prepared as a test food. Twenty dentate participants (10 men, 10 women; mean age 21 years) took part in this study. Each participant masticated 1 piece of RG gum for 3, 6, 9, 15, and 25 cycles, and this task was repeated 3 times consecutively (total n=15 for each participant). The boluses were retrieved and flattened to 1-mm-thick wafers and scanned with a flatbed scanner. The digital images were analyzed using ImageJ software equipped with a custom-built plug-in to measure the geometric dispersion (GD) of baseline red segment. The predictive criterion validity of this method was determined by correlating GD to the number of mastication cycles. The hardness and mass of RG chewing gum were measured before and after mastication. Hardness loss (%) and mass loss (%) were then calculated and compared with those of a commercially available chewing gum.

PURPOSE: The purpose of this study was to develop and validate a novel instrument, termed the questionnaire on perceived prosthodontic treatment needs (PPTN), that assesses perceived prosthodontic treatment needs in adults.

MATERIAL AND METHODS: The PPTN was developed following a literature review, consultation with healthcare workers, and patient interviews. It included 15 questions and a self-rated need for prosthodontic treatment, categorized on a Likert scale. A cross-sectional descriptive study was completed on 193 dental patients seeking or receiving prosthodontic treatment.

PURPOSE: The purpose of this finite element analysis study was to evaluate the biomechanical behavior (stress distribution pattern) in the mandibular overdenture, mucosa, bone, and implants when retained with 2 standard implants or 2 mini implants under unilateral or bilateral loading conditions.

MATERIAL AND METHODS: A patient with edentulous mandible and his denture was scanned with cone beam computed tomography (CBCT), and a 3D mandibular model was created in the Mimics software program by using the CBCT digital imaging and communications in medicine (DICOM) images. The model was transferred to the 3Matics software program to form a 2-mm-thick mucosal layer and to assemble the denture DICOM file. A 12-mm-long standard implant (Ø3.5 mm) and a mini dental implant (Ø2.5 mm) along with the LOCATOR male attachments (height 4 mm) were designed by using the SOLIDWORKS software program. Two standard or 2 mini implants in the canine region were embedded separately in the 3D assembled model. The base of the mandible was fixed, and vertical compressive loads of 100 N were applied unilaterally and bilaterally in the first molar region. The material properties for acrylic resin (denture), titanium (implants), mucosa (tissue), and bone (mandible) were allocated. Maximum von Mises stress and strain values were obtained and analyzed.

RESULTS: Maximum stresses of 9.78 MPa (bilaterally) and 11.98 MPa (unilaterally) were observed in 2 mini implants as compared with 3.12 MPa (bilaterally) and 3.81 MPa (unilaterally) in 2 standard implants. The stress values in the mandible were observed to be almost double the mini implants as compared with the standard implants. The stresses in the denture were in the range of 3.21 MPa and 3.83 MPa and in the mucosa of 0.68 MPa and 0.7 MPa for 2 implants under unilateral and bilateral loading conditions. The strain values shown similar trends with both implant types under bilateral and unilateral loading.

PURPOSE: The purpose of this finite element analysis study was to evaluate stress and strain distribution patterns in 2-implant mandibular overdentures with different positions and angulations of implants under unilateral and bilateral loading.

MATERIAL AND METHODS: A cone beam computed tomography (CBCT)-based, 3-dimensional (3D) model of the mandible and an intraoral scanning-based 3D model of the denture were developed in the Mimics software program. A 3D model of a standard-sized implant with a low-profile overdenture attachment (LOCATOR) was developed in the Solidworks software program. Two implants were inserted in the 3D model of the mandible, with implants placed at different positions, 5, 10, 15, and 20 mm from the midline, and different distal angulations, 0-5, 0-10, 0-15, 5-5, 10-10, and 15-15 degrees (at 10-mm distance), in the 3Matics software program. Unilateral and bilateral vertical loads of 100 N were applied on the first molars in the ANSYS software program to record maximum von Mises stresses and strain values.

RESULTS: The stresses in the implants were maximum when placed at a 20-mm distance (4.18 MPa under unilateral and 4.2 MPa under bilateral loading), while for the implants placed at 5 mm, 10 mm, and 15 mm, the indicated stresses were less than 2.46 MPa following an increasing trend with an increase in the distance. The stresses in the implants were maximum when placed at 15-15-degree angulations (0.93 under unilateral and 0.92 MPa under bilateral loading). For lower angulations, the stresses on the implants ranged from 0.05 to 0.87 MPa. No specific trend was observed in stresses and strains with 0-5-, 0-10-, and 0-15-degree angulations, but an increasing trend was observed with 5-5-, 10-10-, and 15-15-degree angulations under unilateral loading. Under bilateral loading, the stresses and strains on the implants and the mandible showed negligible variations across all 6 angulations.

PURPOSE: The purpose of this in vitro study was to evaluate the crestal strain around 2 implants to support mandibular overdentures when placed at different positions.

MATERIAL AND METHODS: Edentulous mandibles were 3-dimensionally (3D) designed separately with 2 holes for implant placement at similar distances of 5, 10, 15, and 20 mm from the midline, resulting in 4 study conditions. The complete denture models were 3D designed and printed from digital imaging and communications in medicine (DICOM) images after scanning the patient's denture. Two 4.3×12-mm dummy implants were placed in the preplanned holes. Two linear strain gauges were attached on the crest of the mesial and distal side of each implant (CH1, CH2, CH3, and CH4) and connected to a computer to record the electrical signals. Male LOCATOR attachments were attached, the mucosal layer simulated, and the denture picked up with pink female nylon caps. A unilateral and bilateral force of 100 N was maintained for 10 seconds for each model in a universal testing machine while recording the maximum strains in the DCS-100A KYOWA computer software program. Data were analyzed by using 1-way analysis of variance, the Tukey post hoc test, and the paired t test (α=.05).

PURPOSE: The purpose of this 3D finite element analysis study was to evaluate the biomechanical behavior of 2-implant mandibular overdentures (2IMO) and their individual components by using implants of different diameters.

MATERIAL AND METHODS: A 3D mandibular model was obtained from the cone beam computed tomography (CBCT) images of a 59-year-old edentulous man, and a 3D denture model was developed from intraoral scanning files in the Mimics software program. A 3D model of different diameters of implants (2.5 mm, 3.0 mm, 3.5 mm, and 4.0 mm) with a LOCATOR attachment was developed in the Solidworks software program. Two same-sized implants were inserted in the mandibular model at 10 mm from the midline in the 3Matics software program. A vertical load of 100 N was applied on the first molar region on the right side or both sides in the ANSYS software program. The maximum von Mises stresses and strains were recorded and analyzed.

RESULTS: Stresses within the implants decreased with an increase in diameter (from 2.5 mm to 3 mm, 3.5 mm, and 4.0 mm) of the implants. The highest stresses were observed with 2.5-mm-diameter implants (0.949 MPa under unilateral and 0.915 MPa under bilateral loading) and the lowest with Ø4-mm implants (0.710 MPa under unilateral and 0.703 MPa under bilateral loading). The strains on the implants ranged between 0.0000056 and 0.0000097, and those on the mandible ranged between 0.0000513 and 0.0000566 across all diameters of the implants without following a specific trend.

PURPOSE: The purpose of this in vitro study was to evaluate and compare the accuracy of 3D digital casts generated by 4 photogrammetry software programs (Agisoft Metashape, 3DF Zephyr, Meshroom, and Polycam) and casts from 2 conventional impression materials (alginate and polyvinyl siloxane [PVS]) for the fabrication of nasal maxillofacial prostheses.

MATERIAL AND METHODS: A stone cast of a patient's nose was used as the basis for generating a reference digital 3D cast and another 54 test 3D casts. The reference cast was created by scanning the stone cast using a FARO Optor Lab 3D scanner. The 54 test 3D casts were generated and divided into 6 test groups as follows: Agisoft group: 9 3D casts generated using Agisoft Metashape, a commercial personal computer (PC) software program; 3DF Zephyr group: 9 3D casts generated using 3DF Zephyr, a commercial PC software program; Meshroom group: 9 3D casts generated using Meshroom, a free PC software program; Polycam group: 9 3D casts generated using the Polycam, a commercial Android cloud application; PVS group: 9 3D casts generated indirectly by 3D scanning a gypsum cast made from a polyvinyl siloxane (PVS) impression of the stone nose cast; and Alginate group: 9 3D casts generated indirectly by scanning a master cast made using alginate impressions of the stone nose cast. Deviation measurements of the produced specimens were analyzed using the Geomagic Control X software program, and statistical comparisons were performed employing the Kruskal-Wallis test (α=.05).

RESULTS: The results showed that the 3DF Zephyr group had the smallest deviation measurements (median: 0.057 mm ±0.012) among the 4 photogrammetry software programs, while the alginate impression group had the largest deviations (median: 0.151 mm ±0.094) of the 2 conventional impression materials. Significant differences were observed among the 4 photogrammetry software programs and the 2 conventional impression materials (H=39.41, df=5, P.05).

PURPOSE: The purpose of this prospective randomized controlled clinical study was to evaluate crest bone-level changes and patient satisfaction with mandibular overdentures retained by 1 or 2 titanium-zirconium (Ti-Zr) implants with immediate loading protocols after 1 year.

MATERIAL AND METHODS: Thirty-six Ti-Zr implants were placed in 24 participants (single central implant in 12 participants and 2 interforaminal implants in 11 participants) by a single operator. LOCATOR attachments were used to retain the mandibular overdentures with an immediate loading protocol, and observations were made at 1 month and 1 year. Changes to the crestal bone level were evaluated with digital periapical radiographs. A 100-mm visual analog scale (VAS) was used to evaluate patient satisfaction. The Mann-Whitney U test was used to analyze the data.

RESULTS: At 1 month, the mean crestal bone loss was 0.23 mm in the 2-implant group (n=22) and 0.39 mm (P=.181) in the single-implant group (n=11). At 1 year, the bone loss was 0.67 mm in the 2-implant group and 0.88 mm (P=.248) in the single-implant group. The mean VAS score for patient satisfaction level increased from 38.3% to 49.7% for single-implant participants and from 40.5% to 54.8% for 2-implant participants 1 month after implant placement (P=.250) and from 38.3% to 54.5% for single-implant participants and from 40.5% to 58.9% for 2-implant participants after 1 year (P=.341).

PURPOSE: The purpose of this prospective clinical study was to evaluate correlations between different implant positions and crestal bone loss and between interimplant distance and the crestal bone loss in patients with 2IMOs with immediate loading protocols at 1-year follow-up.

MATERIAL AND METHODS: A total of 24 participants (13 men, 11 women, mean ±standard deviation age 63.25 ±10.76 years) were treated with 2IMOs (48 Ti-Zr implants) by a single operator between August 2015 and October 2020. The implant diameters (3.3 mm or 4.1 mm) and lengths (10 mm or 12 mm) were selected based on the crestal bone width, and the implants were placed, if possible, in the canine regions. Implant positions and interimplant distance (mm) were measured intraorally with dividers. Prefabricated mandibular dentures were immediately loaded with the LOCATOR-attachments by using a direct intraoral pickup procedure. Crestal bone-level changes were measured with a software program on the mesial and distal sides of each implant from periapical radiographs made with a paralleling technique (at baseline and 1-year follow-up). The measurement values were normalized. The Spearman rho correlation test and paired samples t tests were used for data analysis (α=.05).

RESULTS: The mean ±standard deviation position of the implants from the midline was 8.78 ±2.25 mm (9.00 ±2.22 mm right side, 8.56 ±2.31 mm left side), and the mean interimplant distance was 16.94 ±4.03 mm. At 1-year follow-up, the mean ±standard deviation crestal bone loss was 0.50 ±0.47 mm (n=48) (0.57 ±0.65 mm mesial, 0.43 ±0.53 mm distal). The mean ±standard deviation crestal bone loss was 0.46 ±0.4 mm with Ø3.3-mm implants (n=42) and 0.9 ±0.8 mm with Ø4.1-mm implants (n=6) (P=.005). Implant positions were negatively correlated (rs=-0.37) with the crestal bone loss, and the correlation was significant (P=.009). Interimplant distances were also negatively correlated with crestal bone loss (rs=-0.60; P=.002). Bone loss on the mesial side was positively correlated with that on the distal side rs=0.20; however, the correlation was not significant (P=.16).

PURPOSE: The purpose of this bibliometric study was to analyze the characteristics of the Journal of Prosthetic Dentistry between 1970 and 2019.

MATERIAL AND METHODS: The Web of Science Core Collection was used to retrieve 9 categories of the Journal of Prosthetic Dentistry, including keywords and terms used, cited documents published, the countries and organizations of the authors, references, and sources cited during this period. Data were exported to a software program and analyzed for each 10-year period and for the entire 50 years. The highest 10 in each category were reported. Co-occurrence, couthorships, and linkage were also reported.

RESULTS: A total of 11 989 records were reached by the search on the Web of Science Core Collection database; of which, 10 638 (92.9%) were included in the analysis. Articles made up 91.1%, of all records, with 217 review documents (1.8%). The most productive decade was 1980 to 1989 with 2936 documents. The total number of citations of all documents (available period 1980 to 2019) including self-citations was 155 112. During the period 1970 to 2019, 14 837 terms were used. The total number of keywords was 4933 (available period 1990 to 2019). There were 15 382 authors, 82 countries, and 2113 organizations identified in articles published in the Journal of Prosthetic Dentistry during this period, with most from the United States. There were 43 027 authors, 95 324 references, and 14 594 sources cited in the Journal of Prosthetic Dentistry during the period surveyed.

PURPOSE: The purpose of this in vitro study was to evaluate the significance of geometric heterogeneity on complete arch implant scanning by using a novel auxiliary geometric device. Three different clinical simulations were tested to assess its significance. The study also assessed whether scans produced using the auxiliary device would meet a clinically acceptable threshold.

MATERIAL AND METHODS: A total of 60 scans (n=20) were performed using an intraoral scanner in 3 different clinical simulations: 2 parallel implants, 4 parallel implants, and 4 implants with a 30-degree posterior angulation of the distal implants. Scanning alternated between using the auxiliary geometric scanning device (test groups; 4IP+, 4IA+, 2IP+) and not using the device (control groups; 4IP-, 4IA-, 2IP-). A reference scan for each model was prepared from a high precision laboratory scanner. The scans were analyzed for accuracy in 3-dimensional deviation, interimplant distance deviation, and angular deviation by using an inspection software program. The effect of the auxiliary device was statistically analyzed by comparing scans of the same group using the paired t test for normally distributed data and the Wilcoxon Signed Rank test when data were not normally distributed (α=.05).

PURPOSE: The purpose of this systematic review was to gather, compare, and appraise studies that attempted to determine the biological and mechanical tolerance of misfits.

MATERIAL AND METHODS: The review protocol was published in the Prospective Register for Systematic Reviews (PROSPERO; registration no. CRD42021268399) and follows the Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was conducted through PubMed, Ebscohost, and Web of Science followed by a manual search up to December 2021.

RESULTS: A total of 413 manuscripts were identified by electronic and manual search. After removing duplicates, nonrelevant titles, and abstract screening, 62 manuscripts were eligible for full-text assessment. Finally, a total of 13 articles (1 cross-sectional study, 1 retrospective and prospective, 7 in vitro studies, and 4 animal studies) met the eligibility criteria and were included in this review. A wide range of tolerable misfits were reported. Vertical misfit up to 1 mm and horizontal misfit up to 345 μm were associated with no adverse outcomes.

PURPOSE: The purpose of this in vitro and clinical study was to evaluate the effect of different build orientations on the adaptation of removable partial denture frameworks fabricated by SLM technology in vitro and to compare the adaptation of the SLM and conventional RPD frameworks clinically.

MATERIAL AND METHODS: A master model simulating a maxillary arch of Kennedy class III modification 1 was scanned and duplicated to create a virtual 3D cast and reference cast. Four groups (n=40) of Co-Cr RPD frameworks were fabricated. For the SLM groups, the Co-Cr framework was virtually designed and exported for SLM printing. The SLM printing was done in 3 different build orientations: 0-degree (n=10), 45-degree (n=10), and 90-degree (n=10) groups. Other Co-Cr frameworks were conventionally cast (n=10). All Co-Cr frameworks were scanned and virtually superimposed with the master model using a surface-matching software program. The gap under 9 selected points in the palatal major connectors was analyzed and calculated. A smaller gap indicates more surface adaptation and close contact between the palatal major connector and the master model. The data were analyzed using the Kruskal-Wallis and Dunnett T3 tests (α=.05). Three patients with a partially dentate maxillary arch were enrolled in the clinical part based on inclusion criteria. Two RPD frameworks were provided for each patient (conventional casting and SLM printing). The adaptation of each framework was assessed by measuring the gap between the palatal major connector of the framework and the palate with light-body silicone. The differences in adaptation between the conventional and SLM frameworks were compared by using independent t tests (α=.05).

PURPOSE: The purpose of this systematic review was to compare the cost-effectiveness and PROMs between digitally and conventionally fabricated complete dentures.

MATERIAL AND METHODS: An electronic search of publications from 2011 to mid-2023 was established using PubMed/Medline, EBSCOhost, and Google Scholar. Retrospective, prospective, randomized controlled, and randomized crossover clinical studies on at least 10 participants were included. A total of 540 articles were identified and assessed at the title, abstract, and full article level, resulting in the inclusion of 14 articles. Data on cost, number of visits, patient satisfaction, and oral health-related quality of life were examined and reported.

RESULTS: The systematic review included 572 digitally fabricated complete dentures and 939 conventionally fabricated complete dentures inserted in 1300 patients. Digitally fabricated complete dentures require less clinical time with a lower total cost, despite higher material costs compared with the conventional fabrication technique. Digitally and conventionally fabricated complete dentures were found to have significant effects on mastication efficiency, comfort, retention, stability, ease of cleaning, phonetics, and overall patient satisfaction, as well as social disability, functional limitation, psychological discomfort, physical pain, and handicap.

PURPOSE: The purpose of this in vitro study was to determine the wetting properties of 3 different commercially available denture base resin materials with artificial salivary substitute by using contact angle measurements and to compare these properties before and after thermocycling.

MATERIAL AND METHODS: A total 120 specimens were fabricated with 3 different denture base materials (n=40): heat-polymerized polymethylmethacrylate (DenTek), injection-molded nylon polyamide (Valplast), and microwave polymerized (VIPI WAVE). The advancing and receding contact angles were measured with a goniometer by using the WinDrop++ software program. The contact angle hysteresis was calculated from the advancing and receding contact angles values. The same specimens were subjected to thermocycling to measure the advancing and receding contact angles values. The comparative evaluation was carried out before and after thermocycling.