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The Journal of Prosthetic Dentistry Oct 2023Gingival displacement is used in prosthodontics to obtain an accurate impression. However, randomized clinical trials to analyze the performance of different gingival...
STATEMENT OF PROBLEM
Gingival displacement is used in prosthodontics to obtain an accurate impression. However, randomized clinical trials to analyze the performance of different gingival displacement products are lacking.
PURPOSE
The purpose of this prospective, comparative randomized clinical trial was to evaluate the clinical effectiveness of 3 gingival displacement techniques: Racegel cordless, Racegel with a cord, and Racestyptine with a cord.
MATERIAL AND METHODS
A prospective, multicenter randomized, open label, 3-arm parallel group study was carried out in private dental practices. Patients with prepared teeth with healthy gingiva were recruited to make impressions before and after gingival displacement, which were digitized. Lateral and vertical gingival displacements were measured with computer-aided 3-dimensional analysis performed by a single operator who was blinded to the technique and the patient. For mean lateral gingival displacement, each gingival displacement method was compared with a required clinical value of 200 µm with the Student t test. The comparison of means among the 3 groups was performed using an ANOVA. Periodontal indices were recorded immediately and 7 to 14 days after gingival displacement. The percentages were compared with the chi-squared test or the Fisher exact test (α=.05 for all tests).
RESULTS
Eighty-eight participants were enrolled. The mean lateral gingival displacement obtained by Racestyptine with a cord (253 ±59 µm, P<.001) and by Racegel with a cord (247 ±61 µm, P<.001) were significantly higher than 200 µm. Lateral displacement observed with Racegel cordless was 207 ±57 µm (P=.53). For vertical gingival displacement, no difference among the 3 techniques was found. The astringent effect of these products was confirmed by the absence of crevicular fluid or bleeding. No periodontal damage was observed immediately or 7-14 days after displacement.
CONCLUSIONS
The study showed that cord impregnated with Racestyptine and Racegel with or without a cord provided a sufficient sulcus opening before impression making in prosthodontics, consistent with the clinical requirements for lateral displacement.
PubMed: 37919130
DOI: 10.1016/j.prosdent.2023.09.027 -
Journal of Applied Oral Science :... 2023The use of a fiber glass post (FGP) type and choice of FGP diameter to restore endodontically treated incisors without ferrule is controversial. This study evaluated...
OBJECTIVE
The use of a fiber glass post (FGP) type and choice of FGP diameter to restore endodontically treated incisors without ferrule is controversial. This study evaluated survival rate and failure mode of severely compromised central incisors without ferrule rehabilitated using resin-based composite (RBC) with or without FGP with different diameters.
METHODOLOGY
A total of 60 decoronated bovine incisors without a ferrule were endodontically treated and prepared for 1.4, 1.6, and 1.8 mm diameter FGPs (Whitepost System DC 0.5, Fit 0.4, and DCE 0.5; FGM). Half of the teeth received FGPs cemented using dual-cure resin cement (Allcem Core; FGM), the other half were filled using only bulk-fill RBC (OPUS Bulk Fill; FGM). The crowns were directly restored with RBC. The roots were embedded in polystyrene resin and the periodontal ligament was simulated with polyether impression material. Fatigue testing was conducted under 5 Hz cyclic loading at 30 degrees to the incisal edge, beginning at 50 N (5,000 cycles) as a warmup. After, the load was increased 100 N every 15,000 cycles until fracture occurred. All specimens were subjected to transillumination, micro-CT analysis, and digital radiography before and after fatigue testing. Fracture mode was classified according to severity and repair potential. Data were analyzed with Kaplan-Meier survival test and post hoc log-rank test (α=0.05) for pairwise comparisons.
RESULTS
Using FGP significantly increased the number of cycles to failure, irrespective of FGP diameters (p=0.001). The FGP diameters had no statistically significant effect on cycles to failure or failure mode.
CONCLUSION
Using FGP without ferrule improved survival rate of structurally severely compromised central incisors compared with rehabilitation without FGP. The diameter of the FGPs had no effect on the survival rate and failure mode.
Topics: Animals; Cattle; Post and Core Technique; Composite Resins; Tooth, Nonvital; Crowns; Dental Materials; Glass; Dental Stress Analysis; Tooth Fractures; Dental Restoration Failure
PubMed: 37909530
DOI: 10.1590/1678-7757-2023-0241 -
JPMA. the Journal of the Pakistan... Oct 2023To determine the current trends in complete denture education in undergraduate dental colleges.
OBJECTIVE
To determine the current trends in complete denture education in undergraduate dental colleges.
METHODS
The survey-based study was conducted in April and May 2020 at undergraduate dental colleges of Pakistan, and comprised heads of the Prosthodontics Department at all dental colleges across Pakistan having at least one batch of final year dental students. Data was collected using an online predesigned questionnaire that explored theoretical and practical teaching patterns of complete denture prosthodontics in the undergraduate years, and the materials and practices of students when constructing complete dentures in the clinics. The participants were given the option of choosing more than one option where needed. Data was analysed using SPSS 23.
RESULTS
Of the 49 subjects approached, 40(81.6%) returned the forms duly filled; 11(27.5%) from public-sector institutions and 29(72.5%) from the private sector. There were 26(65%) institutions which required that their undergraduate students fabricate 2-4 conventional complete dentures. In all 40(100%) colleges, faculty gave live clinical demonstrations before students fabricated conventional complete dentures in the outpatient departments. Teaching strategy included small group discussions in 25(62.5%) institutions. Green stick 40(100%), zinc oxide eugenol 40(100%) and impression compound 39(97.2%) were the materials of choice for various steps of impression making. In all the 40(100%) institutions, students fabricated conventional complete dentures during their prosthodontics rotation. Immediate, copy and overdentures were constructed by students in 8(20%), 3(7.5%) and 8(20%) institutions, respectively.
CONCLUSION
Majority of the dental schools used similar impression materials and techniques for fabricating conventional complete dentures. Didactic teaching of conventional and unconventional complete dentures was being carried out at a huge majority of the dental institutions studied.
Topics: Humans; Curriculum; Pakistan; Education, Dental; Schools, Dental; Denture, Complete; Students
PubMed: 37876065
DOI: 10.47391/JPMA.9710 -
BMC Oral Health Oct 2023The variabilities in design and material of scan bodies have a major role in the positional transfer accuracy of implants. The purpose of this invitro study was to...
BACKGROUND
The variabilities in design and material of scan bodies have a major role in the positional transfer accuracy of implants. The purpose of this invitro study was to compare the 3D transfer accuracy (trueness and precision) of titanium base (TB) abutment position provided by 2 different scan bodies: one-piece scan body (SB) in comparison to two-piece healing abutment and scan peg (HA-SP).
METHODS
A maxillary model with a dummy implant in the 2nd premolar (Proactive Tapered Implant; Neoss) was 3D printed and TB (Ti Neolink Mono; Neoss) was tightened on the implant and scanned by using a laboratory scanner (inEos X5; Dentsply Sirona) (reference scan). An SB (Elos Medtech) and an HA-SP (Neoss) were subsequently connected to the implant and were scanned 10 times each by using the same scanner (test scans). All the scans were exported as STL files and imported into CAD software where the TBs were formed. Test scans were superimposed on reference scans for transfer accuracy analysis using 3D metrology software (GOM Inspect; GOM GmbH) in terms of angular deviation in vertical and horizontal directions, linear deviation in each XYZ axis of TBs and total linear deviation in all axes. Statistical analysis was done using independent sample t test. When Levene's test for equality of variances was significant, Welch's t-test was used. (P value < 0.05) RESULTS: Significant differences were found amongst the tested groups in both angular and linear deviation in terms of trueness with less deviation values for the SB group (P < 0.001). For the precision, significant differences were found amongst the tested groups in angular deviation in vertical direction with less deviation value for the SB group compared to HA-SP group (P < 0.001). However, no significant difference was found between the tested groups regarding the angular deviation in horizontal direction (P = 1.000). Moreover, significant differences were found amongst the tested groups in linear deviations with less linear deviations in XYZ axes for SB compared to HA-SP group (P = 0.020, < 0.001, = 0.010 respectively).
CONCLUSIONS
SB showed less angular and linear deviation values in the 3D positional transfer of TB than HA-SP indicating higher degree of accuracy of SB.
Topics: Humans; Computer-Aided Design; Titanium; Dental Impression Technique; Models, Dental; Dental Implants; Imaging, Three-Dimensional
PubMed: 37821890
DOI: 10.1186/s12903-023-03399-9 -
The Saudi Dental Journal Sep 2023Enamel, being the hardest and the highest mineralized tissue of the human body, contains nearly 96% inorganic components and 4% organic compounds and water. Dentin...
Enamel, being the hardest and the highest mineralized tissue of the human body, contains nearly 96% inorganic components and 4% organic compounds and water. Dentin contains 65% inorganic components and 35% organic and water content. The translucency and white appearance of enamel are attributed to Hydroxyapatite (HA), which constitutes the major part of the inorganic component of dental hard tissue. With the advent of nanotechnology, the application of Nanohydroxyapatite (nHA) has piqued interest in dentistry due to its excellent mechanical, physical, and chemical properties. Compared to HA, nHA is found to have superior properties such as increased solubility, high surface energy and better biocompatibility. This is due to the morphological and structural similarity of nanosized hydroxyapatite particles to tooth hydroxyapatite crystals. These nanoparticles have been incorporated into various dental formulations for different applications to ensure comprehensive oral healthcare. To prevent dental caries, several nHA based dentifrices, mouth rinsing solutions and remineralizing pastes have been developed. nHA-based materials, such as nanocomposites, nano impression materials, and nanoceramics, have proven to be very effective in restoring tooth deformities (decay, fracture, and tooth loss). The nHA coating on the surface of the dental implant helps it bind to the bone by forming a biomimetic coating. A recent innovative strategy involves using nHA to reduce dentinal hypersensitivity and to reconstruct periodontal bone defects. The purpose of the present review is to discuss the different applications of nHA in dentistry, especially in preventive and restorative dentistry, dental implantology, bleaching and dentine hypersensitivity management.
PubMed: 37817794
DOI: 10.1016/j.sdentj.2023.05.018 -
The Saudi Dental Journal Sep 2023Digitalized workflow eliminates the need for the tray, impression materials, its decontamination, packaging and shipping, pouring with plaster, cast fabrication,...
Digitalized workflow eliminates the need for the tray, impression materials, its decontamination, packaging and shipping, pouring with plaster, cast fabrication, mounting in an articulator, reducing storage spaces, and the risks of any loss or fracture of the plaster model is overcome by archiving on the computer. This clinical investigation aimed to evaluate the effectiveness of the fully digitalized rehabilitation [implant-supported prosthesis] method in partially edentulous patients and with TMD, using advanced software. Twelve patients requiring implant-supported prosthesis in the mandibular molar area with Temporomandibular disorders [TMD] were selected. The fully digitalized rehabilitation method with advanced software was used for rehabilitation. For each subject, Optical impressions, CBCT scan, and Digital recording of jaw movement data. Guided implant surgery and digitalized prosthetic rehabilitation; were performed. The effectiveness of the digitalized workflow was assessed by evaluating the changes in the joint symptoms before and after the end of the treatment, changes in the electromyographic tracings, the precision of the prosthetic artefact, assessed through the amount of chair adjustment operating time and the number of retouching/ modifications to be carried out before the completion of the work. The results showed that the mean operative time required in 12 patients was 9.42 min, significantly less than the time recorded in previous studies when the medium mean was 16.00 min. The mean number of touch-ups [adjustments] was less than 3, most of which were on the interproximal surfaces. There were no significant changes recorded in the electromyography tracings. There were also no changes in joint symptoms. It was found that this way of working was entirely reliable and significantly reduced operating times and the number of appointments. Digital flow is beneficial ei dysfunctional patients, not about improvements in temporomandibular symptoms but in times of operability and prosthetic retouching.
PubMed: 37817790
DOI: 10.1016/j.sdentj.2023.05.024 -
Clinical and Experimental Dental... Dec 2023The aim of this in vitro study was to evaluate the effect of arch size and implant angulation on the accuracy of digital impression in two intraoral scanners of Trios...
OBJECTIVES
The aim of this in vitro study was to evaluate the effect of arch size and implant angulation on the accuracy of digital impression in two intraoral scanners of Trios (3shape) and CEREC (Omnicam).
MATERIAL AND METHODS
Four acrylic models each including six implants at sites 11, 12, 15, 17, 23, and 27 were used, including large with parallel implants, large with angled implants, small with parallel implants, and small with angled implants. After tightening the scan bodies, distance measurements were done using a coordinate measuring machine. Then, each model was scanned 10 times using each scanner. Trueness and precision measurements were finally computed.
RESULTS
The trueness values ranged from 20 to 260 μm in CEREC Omnicam, and from 40 to 1030 μm in Trios. The precision values ranged from 30 to 190 μm in CEREC Omnicam, while from 50 to 770 μm in Trios. The multivariate test analysis indicated that the measured distances via two scanners and different models show different behaviors. Pairwise interactions between these three variables were significant (p < .05). Pairwise interactions between these variables were also significant. (p < .0001).
CONCLUSIONS
Arch width could affect the accuracy of digital impression; by rotating toward the second quadrant and end points of the scan, errors have increased. However, the angulation of the implants had no effect on the accuracy of digital impression. The CEREC Omnicam scanner showed higher accuracy (trueness and precision) compared to the Trios (3shape) one.
Topics: Imaging, Three-Dimensional; Models, Dental; Computer-Aided Design; Dental Impression Technique; Dental Implants
PubMed: 37786371
DOI: 10.1002/cre2.793 -
Clinical Oral Investigations Nov 2023Disinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming...
OBJECTIVES
Disinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming and exert a negative impact on accuracy and mechanical properties. Thus, this study aimed to prepare disinfecting agents (CHX and AgNO) and silver nanoparticles reduced by a natural plant extract to produce a self-disinfecting dental alginate.
METHODS
Conventional alginate impression material was used in this study. Silver nitrate (0.2% AgNO group) and chlorohexidine (0.2% CHX group) solutions were prepared using distilled water, and these solutions were later employed for alginate preparation. Moreover, a 90% aqueous plant extract was prepared from Boswellia sacra (BS) oleoresin and used to reduce silver nitrate to form silver nanoparticles that were incorporated in the dental alginate preparation (BS+AgNPs group). The plant extract was characterized by gas chromatography/mass spectrometry (GC/MS) analysis while green-synthesized silver nanoparticles (AgNPs) were characterized by UV-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). An agar disc diffusion assay was used to test the antimicrobial activity against Candida albicans, Streptococcus mutans, Escherichia coli, methicillin-resistant and susceptible Staphylococcus aureus strains, and Micrococcus luteus. Agar plates were incubated at 37 ± 1 °C for 24 h to allow microbial growth. Diameters of the circular inhibition zones formed around each specimen were measured digitally by using ImageJ software.
RESULTS
Chemical analysis of the plant extract revealed the presence of 41 volatile and semi-volatile active compounds. UV-Vis spectrophotometry, SEM, and EDX confirmed the formation of spherical silver nanoparticles using the BS extract. CHX, AgNO, and the BS+AgNPs modified groups showed significantly larger inhibition zones than the control group against all tested strains. BS+AgNPs and CHX groups showed comparable efficacy against all tested strains except for Staphylococcus aureus, where the CHX-modified alginate had a significantly higher effect.
CONCLUSIONS AND CLINICAL RELEVANCE
CHX, silver nitrate, and biosynthesized silver nanoparticles could be promising inexpensive potential candidates for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles using Boswellia sacra extract could be a very safe, efficient, and nontoxic way with the additional advantage of a synergistic action between metal ions and the phytotherapeutic agents of the plant extract.
Topics: Alginates; Disinfection; Silver Nitrate; Metal Nanoparticles; Agar; Gas Chromatography-Mass Spectrometry; Silver; Plant Extracts; Staphylococcus aureus; Nanotechnology; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37775587
DOI: 10.1007/s00784-023-05277-8 -
Cureus Aug 2023Addition silicones have revolutionized the field of fixed prosthodontics because of their dimensional stability, sufficient tear strength and excellent detail... (Review)
Review
Addition silicones have revolutionized the field of fixed prosthodontics because of their dimensional stability, sufficient tear strength and excellent detail reproduction. This review study aims to provide a detailed description of the essential variables to be taken into account during the process of making addition silicone impressions in fixed prosthodontics. These variables include the selection of appropriate tray type, size, and fabrication; the use of tray adhesive; gingival displacement techniques; manipulation of the impression material; the choice of the impression material's viscosity; impression techniques; and the proper insertion, removal, disinfection, and pouring of the cast. Additionally, this review aims to help doctors produce high-quality impressions by empowering them to critically assess the impressions to spot mistakes and motivating them to redo impressions that have serious problems before submitting them to the laboratory.
PubMed: 37746395
DOI: 10.7759/cureus.44014 -
Frontiers in Bioengineering and... 2023Mandibular flexure, characterized by unique biomechanical behaviors such as elastic bending and torsion under functional loading, has emerged as a crucial factor in oral... (Review)
Review
Mandibular flexure, characterized by unique biomechanical behaviors such as elastic bending and torsion under functional loading, has emerged as a crucial factor in oral clinical diagnosis and treatment. This paper presents a comprehensive review of the current research status on mandibular flexure, drawing insights from relevant studies retrieved from the PubMed database (www.ncbi.nlm.nih.gov/pubmed), including research conclusions, literature reviews, case reports, and authoritative reference books. This paper thoroughly explores the physiological mechanisms underlying mandibular flexure, discussing different concurrent deformation types and the essential factors influencing this process. Moreover, it explores the profound implications of mandibular flexure on clinical aspects such as bone absorption around dental implants, the precision of prosthesis fabrication, and the selection and design of superstructure materials. Based on the empirical findings, this review provides crucial clinical recommendations. Specifically, it is recommended to exert precise control over the patients mouth opening during impression-taking. Those with a high elastic modulus or bone-tissue-like properties should be prioritized when selecting superstructure materials. Moreover, this review underscores the significance of customizing framework design to accommodate individual variations in facial morphology and occlusal habits. Future research endeavors in this field have the potential to advance clinical diagnosis and treatment approaches, providing opportunities for improvement.
PubMed: 37744259
DOI: 10.3389/fbioe.2023.1238181