Computerized occlusal forces analysis in complete dentures fabricated by additive and subtractive techniques

Clinical outcomes of milled, 3D-printed, and conventional complete dentures in edentulous patients: A systematic review and meta-analysis

PURPOSE

This systematic review aims to compare clinical outcomes of digital dentures with conventional dentures.

MATERIALS AND METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in Prospero. The formulated population, intervention, comparison, outcome (PICO) question was "What is the clinical outcome of digital versus conventional complete dentures (CDs) in edentulous patients?". The search strategy used three main electronic databases and an additional manual search was completed in August 2023 by following an established search strategy. Initial inclusion was based on titles and abstracts, followed by a detailed review of selected studies, and clinical studies that evaluated the clinical outcome of digital (milled or 3D-printed) versus conventional CDs were included. A qualitative analysis for clinical studies was used to assess the risk of bias. The certainty of the evidence was assessed according to the grading of recommendations, assessment, development, and evaluations (GRADE) system. In addition, a single-arm meta-analysis was performed to evaluate the retention between digital versus conventional CDs.

RESULTS

The initial search yielded a total of 947 articles, out of which 19 were selected for a comprehensive review, and six met the eligibility criteria to be included in this systematic review. The computer-aided design and computer-aided manufacturing (CAD-CAM) CDs showed increased retention, no relevant differences in oral health-related quality of life (OHRQoL), and shorter working time compared to conventional dentures. Two studies were eligible for meta-analysis; retention was significantly better among CAD-CAM fabricated dentures (standardized mean difference [SMD] 0.501) than conventional dentures. The heterogeneity between studies was high (95% CI: 0.049-0.952).

CONCLUSIONS

Clinically, both the milled and the 3D-printed CD fared better than conventional dentures in terms of retention, reduction in the number of appointments, improved patient comfort, and improved predictable maintenance of the denture. Patients' perceptions and satisfaction were independent of the digital and conventional fabricated dentures.

Micronuclei as an indicator of genotoxic change in epithelial cells of buccal mucosa after panoramic radiographs

BACKGROUND

The radiation released at the time of dental panoramic radiographs causes genotoxic and cytotoxic effects on epithelial cells.

OBJECTIVE

This research aimed to evaluate the changes in the frequencies of micronucleated cells in patients' buccal epithelial cells following dental panoramic radiography.

METHODS

74 patients were recruited for the study who were advised for panoramic radiographs. Using a wooden spatula, the buccal epithelial cells were scraped from both cheeks before to panoramic radiation exposure and ten days after the panoramic radiation exposure. Giemsa stain was used to stain the cells, and 500 cells were scored on a slide to determine the frequency of micronuclei. To determine the difference between the frequency of micronuclei before and after radiation exposure, a paired t-test was used in the statistical analysis.

RESULTS

The proportion of micronuclei cells was 0.11% before radiation exposure and 0.57% following radiation exposure after 10 days. A statistically significant increase in the frequencies of micronuclei was noted after radiation exposure values.

CONCLUSION

This study revealed the genotoxicity of epithelial cells with dental panoramic radiation exposure. It is advised to reduce the use of such radiographs and to use only when there is no other diagnostic tool that is helpful or when absolutely essential.

Analysis of modified palatal surface for better speech in edentulous patients: A clinico-analytical study

BACKGROUND

Phonetics with mechanics and aesthetics are considered cardinal factors contributing to the success of complete dentures.

OBJECTIVE

The aim of the current study was to evaluate the changes in speech in complete denture patients with and without palatal surface changes.

METHODS

The data collected for the study involved completely edentulous Patients (n= 80). Patients were divided into two groups. Group A: Up to 50 years (n= 40); Group B: Above 50 years (n= 40) (including male and female). Each group was further divided into four subgroups for speech analysis-without dentures (A1/B1); with conventional dentures (A2/B2); dentures with a palatogram (A3/B3) and dentures with palate sandblasted (A4/B4). The speech sounds of all patients were evaluated for pitch and intensity using a spectrophotogram (Praat software) and Likert scale. The data so obtained from the quantitative and qualitative analysis were statistically analysed through one-way ANOVA, unpaired student's t-test, and Pearson correlation coefficient. Qualitative analysis was done with the Mann-Whitney U test.

RESULTS

The maximum mean value of the pitch and intensity in Groups A and B was subgroup A3 (Palatogram) 190.37 ± 21.50 and 77.07 ± 7.58, B3 (Palatogram) 190.87 ± 24.36 and 75.33 ± 8.12. When comparing Groups A [A1, A2, A3, A4] and B [B1, B2, B3, B4] on the basis of pitch and intensity, a statistically insignificant value was found. No changes in speech sounds (pitch and intensity) were observed in terms of age. Both quantitative and qualitative analysis results showed that speech sounds in the patients with palatogram, had the highest pitch and intensity and were most clear to the listener and there were statistically significant differences from other groups.

CONCLUSION

Speech was better in palatogram-based dentures in comparison to a sandblasted denture, conventional denture and without denture in terms of qualitative and quantitative analysis. The physiologic nature of the palatogram fabrication technique produces the palatal part of the denture more compatible with the tongue, thus producing better speech.

28Assessment of thermal variations in the pulpal chamber during fabrication of provisionals using two different techniques and three materials

BACKGROUND

The issue of an increase in pulpal temperature affects direct and indirect techniques, where the fabricating material will come in direct contact with the prepared teeth.

OBJECTIVE

The aim of this study was to assess the pulpal thermal variations during provisional fabrication using direct and indirect-direct techniques, with three commonly commercially available provisional fabricating materials.

METHOD

In this vitro analytical study, 120 extracted human teeth were placed in a dentulous mould and dental stone was poured, to create a working model with an embedded natural right maxillary central incisor. Recording of thermal changes in the pulp chamber during provisionalization with direct (technique 1) and indirect-direct (technique 2) using three common types of provisional crown materials. 120 provisional crowns were fabricated using polymethyl methacrylate (DPI) (Group 1), Bis-acryl composite (Protemp 4) (Group 2) and Visible-light polymerizing (VLP) Urethane Dimethacrylate (Revotek LC) (Group 3) by two techniques and recording of peak temperature changes were done. Temperature rise in the pulp chamber was recorded using a thermocouple.

RESULTS

The mean initial and final temperature of the pulp chamber recorded for Groups 1, 2 and 3 was 31.52, 32.56; 31.01, 32.34; 32.29, 34.47 for technique 1 and 29.13, 30.5; 29.29, 31.11; 30.31, 32.65 for technique 2. The mean change in temperature was higher in Group 3 compared to the other groups.

CONCLUSION

The temperature rise detected according to this study was within the safer pulpal health limits with all the investigated materials and techniques. The resin material recommended for clinical use when the direct technique is employed for the fabrication of provisional crowns is bis-acryl composite resin (Protemp-4) as it caused minimal temperature rise in the pulpal chamber.

Validation of Digital Impressions' Accuracy Obtained Using Intraoral and Extraoral Scanners: A Systematic Review

BACKGROUND

At present, the evidence regarding digital impressions' accuracy recorded by using digital scanners is lacking. This systematic review aimed to evaluate whether the type of scanning (intraoral/extraoral) affects the Accuracy of Digital Impressions.

METHOD

Two independent reviewers performed a systematic search in the database both electronically and manually (PubMed, Ebsco HOST, the Cochrane Library, and Google Scholar) for articles published from 1 January 2010 to 1 December 2022. This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO CRD42020188765) and followed the PRISMA statement. The question in focus was as follows: Does the type of scanning (intraoral or extraoral) affect the accuracy of digital impression?

RESULTS

A total of 449 papers were obtained by searching electronically and manually. In total, 15 complete-text papers qualified for assessment based on eligibility criteria. After reading the full-text articles, five studies were excluded. Ten studies were selected for the qualitative analysis. The qualitative data reported that the accuracy of both types of scanners (intraoral and extraoral) lies within the range of clinical acceptability. Nevertheless, the intraoral scanners seem to be more accurate when compared to the extraoral scanners for a partial arch situation.

CONCLUSIONS

Scanning type affects the accuracy of the digital impression. Various factors influence the scanning ability. Intraoral scanners seem to be more accurate compared to extraoral scanners for a partial arch situation. More studies comparing the accuracy of the intraoral scanner and extraoral scanner for a complete arch scan and in an in vivo study setting are needed.

Challenges of E-Learning: Behavioral Intention of Academicians to Use E-Learning during COVID-19 Crisis

The COVID-19 crisis demanded that all educational activities should be performed virtually to follow social distancing guidelines. Therefore, there was a need to perform a research study to assess the effects of external factors on the perceived usefulness, ease of use of e-learning, and the further effect of these perceptions on attitude and intent to use e-learning by using the technology acceptance model (TAM) among academicians at higher education institutions in the Kingdom of Saudi Arabia. Methods: A cross-sectional study was conducted, and data were collected from 263 academicians across Saudi Arabia through an online survey questionnaire using a non-probability purposive sampling technique and analyzed and tested using the SPSS and Smart PLS software. Results: This study found that self-efficacy was positively associated with perceived usefulness at β = 0.143 and p < 0.05, but it had no association with perceived ease of use at β = 0.057 at p > 0.05. System accessibility had a significant and positive relationship with perceived usefulness and perceived ease of use at β = 0.283, β = 0.247, and p < 0.01, respectively. Self-efficacy had a positive effect on perceived usefulness, whereas the subjective norm had no relationship with perceived usefulness and perceived ease of use at β = −0.065 and β = −0.012 at p > 0.05, respectively. Perceived ease of use and perceived usefulness were positively related to attitude towards use, which has a significant influence on intention to use e-learning. Conclusion: Perceived ease of application is the most significant factor (β = 0.556) in developing the attitude among academicians to practice e-learning, followed by perceived usefulness (β = 0.262). Moreover, it can be concluded that system accessibility has a stronger influence on developing perception among academicians about the expediency and ease of application of e-learning than self-efficacy.

Clinical Trial to Assess Physiology and Activity of Masticatory Muscles of Complete Denture Wearer Following Vitamin D Intervention

Background and Objectives: Little information is available on the role of Vitamin D as a micro-nutrient deficiency with masticatory muscle efficiency and its effect on the function of removable prosthesis. The aim of this study was to evaluate the role of vitamin D on masticatory muscle activity among completely edentulous patients and its effect on the retention of removable complete dentures (RCDs). Materials and Methods: A non-randomized clinical control trial was conducted on completely edentulous patients (60.53 ± 7.01 years) in the Indian population between 2017 and 2019. Subjects were evaluated for temporomandibular disorders according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Serum Vitamin D (S Vit D) levels, Ultrasonography (USG), and surface Electromyography (sEMG) readings of the masseter muscle were recorded at enrolment (Level 0), after 3 months of Vitamin D therapy (Level 3), and after consecutive 3 months of maintenance therapy, i.e., after 6 months from baseline (Level 6). The fabrication of new RCDs was done for all after the enrolment, and the retention of RCDs was assessed by asking a question regarding denture retention and asking respondents to mark their satisfaction on a 5-point Likert scale. Data were analysed using ANOVA, Paired'-test and Pearson correlation coefficients. A p-value less than 0.05 indicated a statistically significant association. Results: Between enrolment and a six-month follow-up, S Vit D levels showed an increase from 16.03 ± 5.68 ng/mL to 31.35 ± 9.28 ng/mL, showing an increase of 15.32 ± 9.38 ng/mL (95.57% rise). Statistically significant values were observed for USG and sEMG. Conclusions: Results showed that S Vit D affects masticatory muscle activity by improving its thickness and boosting its tonicity. Healthy muscles assist in the retention of RCDs, consequently aiding in mastication, speech, and phonetics, hence improving patient satisfaction. Clinical implication: Acknowledging the fact that the prevalence of Vitamin D deficiency is worldwide. We suggest Vitamin D therapy as a nutritional intervention among the elderly completely edentulous population, following dietary counselling, and consider Vitamin D therapy to be an adjunct to nutritional counselling for improving masticatory muscle activity and efficiency, which aids in RCD retention and stability. Consequently, improving oral health-related quality of life for individuals.

Retentive Forces and Deformation of Fitting Surface in RPD Clasp Made of Polyether-Ether-Ketone (PEEK)

BACKGROUND

Polyetheretherketone (PEEK) has provided the option to fabricate RPDs with aesthetics unlike metal RPDs, but little attention has been paid to its suitability, especially towards the retentive forces and deformation of the clasp. This study aimed to examine the retentive forces and the fitting surface (inner surface) deformation of clasps made from PEEK and compare it with cobalt-chromium (Co-Cr) clasp.

METHODS

Forty-two circumferential clasps (14 Co-Cr and 28 PEEK) were fabricated and divided into two groups with clasp undercuts (0.25 mm and 0.5 mm) with thicknesses of 1 mm and 1.5 mm. Each was examined for retentive forces after cycle test on its abutment for 360 cycles. Initial and final retentive forces were recorded. The fitting surface deformation was determined using 3-Matic research analysis software.

RESULTS

The results revealed that highest mean initial retentive force was of Co-Cr clasps with 0.50 mm undercut 22.26 N (±10.15 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 3.35 N (±0.72 N) and highest mean final retentive force was the Co-Cr clasps with 0.50 mm undercut 21.40 N (±9.66 N), and the lowest was the 1 mm PEEK clasps with 0.25 mm undercut 2.71 N (±0.47 N). PEEK clasps had a lower retentive force than Co-Cr clasps with 0.50 undercut. PEEK clasps (1.5 mm) at 0.25 mm undercut had the least deformation (35.3 µm). PEEK showed significantly less deformation (p ≤ 0.014) than Co-Cr.

CONCLUSION

The deformation of PEEK clasps fitting surface was lower than Co-Cr clasps and retentive forces were close to the Co-Cr clasps, suggesting the use of PEEK as an aesthetic clasp option for RPD framework.

Dimensional Stability of Light-Activated Urethane Dimethacrylate Denture Base Resins

An accurate and dimensionally stable trial denture base is required for a successful denture. The aim of this in vitro study was to assess the dimensional stability of a light-activated urethane dimethacrylate (UDMA) visible light cure (VLC) denture base with three fabrication techniques and different curing cycles. Forty-five VLC denture base samples were divided evenly into three groups. Group A used a conventional fabrication technique with a curing cycle of 5 min. Group B used a modified fabrication technique with two 4-min curing cycles. Group C used a multi-step fabrication technique with three curing cycles (4 min, plus 4 min, plus 2 min). The samples were sectioned and observed under a stereomicroscope to measure the discrepancy between the sample and the master cast. The mean dimensional discrepancy (mm) at the molar region at mid-palate, after 24 h in Group A, B and C was 0.790 mm, 0.741 mm and 0.379 mm, respectively; at the right ridge crest, it was 0.567, 0.408 and 0.185, while at the left ridge crest it was 0.475, 0.331 and 0.125, respectively. Statistical analysis showed significantly different dimensional discrepancies among the groups at all three sites; right ridge crest (F = 93.54, p < 0.001), left ridge crest (F = 105.96, p < 0.001) and mid-palate (F = 125.53, p < 0.001). Within the limitations of this laboratory study, it can be concluded that the denture base using a multi-step fabrication technique with three curing cycles provides better adaptation than the conventional technique. The significance of the study is that clinicians should consider performing denture base fabrication using a multi-step technique to enhance adaptation and hence the stability of the dentures for patients.

Fracture toughness of 3D printed denture teeth

BACKGROUND

Advances in digital dentistry lead to use of three-dimensional (3D) printed resin denture teeth. Fracture toughness of these teeth must be assessed.

OBJECTIVE

This study aimed to compare the chipping and indirect tensile fracture resistance of denture teeth fabricated by 3D printing technique with traditionally fabricated resin denture teeth.

METHOD

Four groups (Gr) were made (n= 50/group): Gr-1 3D printed denture teeth (denture teeth; Formlabs Inc., Somerville, MA, USA), Gr-2 SR-Orthosit-PE (Ivoclar Vivadent AG), Gr-3 Portrait IPN (Dentsply Sirona), Gr-4 Pala Premium 8 (Heraeus Kulzer GmbH). Stereolithography 3D printing was used to create the methacrylate-based photopolymerized resin teeth models and remaining group teeth were collected commercially. A 1 mm/min chipping and indirect tensile fracture speed tests were carried out till fracture occurred. The data so obtained were statistically analysed using one-way analysis of variance with Tukey's honestly significant difference multiple comparisons test (p< 0.05). At the end of the test, the fractured areas of the specimens were evaluated by the chief researcher to assess the fracture pattern of the teeth.

RESULTS

The indirect tensile fracture values of the 3D printed teeth were more than that of Pala Premium-8 and SR-Orthosit-PE but it was lower than that of Portrait IPN teeth. In chipping test, buccal chipping of the loaded cusp was seen in 3D printed resin without distortion and in indirect tensile test in 3D printed resin teeth, line of fracture emerges near the loading point propagates from the inner incline of both cusps and extends cervically, unlike in other groups where first deformation occurs then fracture.

CONCLUSION

Prosthetic teeth fabricated by the 3D printing technique using printable resin material provide adequate fracture resistance as denture teeth.

Fracture load assessment of digitally fabricated post and prefabricated fibre post in endodontically treated teeth

BACKGROUND

Endodontically treated teeth are structurally more susceptible to root fractures. Proper tooth restorations with digitally fabricated or fibre post following endodontic therapy is essential to restore function and esthetics.

OBJECTIVE

The aim of this in vitro study is to evaluate the fracture load of digitally fabricated and prefabricated fibre posts in endodontically treated teeth.

METHODS

Sixty extracted human single rooted teeth were selected. The crowns were sectioned at the cement-enamel junction to standardize the remaining root length at 15 mm from the apices. Cleaning, shaping and obturation was done using conventional step back technique to an ISO K-file size 40. The roots were divided into two groups of 30 samples each: Group S: teeth reinforced with digitally fabricated posts; Group F: teeth reinforced with fibre posts. Each group was further divided into three subgroups (S7, S9, S12, F7, F9, F12) based on lengths 7, 9 and 12 mm at which the posts were cemented. Composite resin core was fabricated and prepared to receive a complete metal crown. Universal testing machine was used to measure the compressive load required to fracture the teeth.

RESULTS

The highest fracture resistance of 1532N was observed with fibre posts at 12 mm of post space length followed by digitally fabricated post 1398N at 12 mm, but the difference was not statistically significant.

CONCLUSION

The highest fracture resistance was observed in the teeth restored with fibre posts with 12 mm length and the lowest with digitally fabricated post with 7 mm length. As the length of post increases irrespective of type of post fracture resistance increased.

Dental implants in growing patients: A systematic review and meta-analysis

BACKGROUND: Dental implants provide a suitable and reliable treatment for the replacement of missing teeth. Very few studies have been reported in the literature regarding the application of dental implants in growing and developing patients. OBJECTIVE: This systematic review with meta-analysis aimed to systematically review the available literature regarding the application of dental implants in growing and developing patients. METHODS: A detailed search in the literature was performed with the help of keywords such as dental implants, treatment planning, children, adolescents, growing patients, and developing jaws. PubMed, Scopus, Web of Sciences, and Ovidsp databases were searched for papers published between 1980 and 2021. The papers focused on children, adolescents, developing jaws, and implants. In this systemic review, the dataset concerned with the type of study, aim, number of patients and specimens included, age of patients, total number of implants placed, total number of implants evaluated, medical history of developmental disorders of teeth such as ectodermal dysplasia, congenital absence of teeth, were evaluated. RESULTS: Out of the total literature searched, 33.45% of studies and case reports documented no complications in any implant treatment. In 47.21% of studies and case reports, there was both success and failure of implants while in 13.21% of studies and case reports there was a complete failure of implants. The most common cause for loss of permanent teeth in growing children and adolescent patients was dental trauma (73.13%) followed by congenital developmental disturbance of teeth (18.19%). CONCLUSION: It can be concluded from this systematic review that the use of implants in edentulous growing patients is determined by several parameters, including the patient’s overall health, the stage of jaw growth, the number of teeth to be replaced, and soft and hard tissue anatomic features. Still, the use of a conservative treatment strategy for missing teeth management in patients with developing jaws is common and recommended until the patient’s growth is completed, as there are chances of changes in the position of dental implants placed in the developing and growing jaws due to the continuous changes taking place in their body. However, placement of implants can be done in these patients successfully with proper treatment planning and taking into account the phase of growth with proper follow-up.