Trends and future perspectives of 3D printing in prosthodontics.

The three-dimensional (3D) printing technology has led to transformative shift in prosthodontics. This review summarizes the evolution, processing techniques, materials, integration of digital plan, challenges, clinical applications and future directions of 3D printing in prosthodontics. It appraises from the launch of 3D printing to its current applications in prosthodontics. The convergence of printing technology with digital dentistry has facilitated the creation of accurate, customized prostheses, redefining treatment planning, design, and manufacturing processes. The progression of this technology is from generating models to prosthesis like-fixed dental prosthesis (FDP), implants, and splints. Additionally, it exhibits more wide capabilities. The exploration of materials for 3D printing provides various options like polymers, ceramics, metals, and hybrids, each with distinctive properties that are applicable to different clinical scenarios. The combination of 3D-printing technology and digital workflow simplifies the processes of data transfer, computer-aided design (CAD) design to fabrication, decreasing errors and chairside time. The clinical benefits include enhanced accuracy, comfort, conservative lab procedures, and economics. Challenges in the technology involve significant aspects like initial investment, material availability, and skill requirements. Future trends emphasize on research for improved materials, bioprinting integration, artificial intelligence (AI) application, regularization efforts to ensure safe and common use of the technology. 3D printing offers promise in prosthodontics, addressing challenges through research. The material improvements will promote its broader adoption and revolutionize the future of dental rehabilitation.

Comparing the influence of cuspal angulation, occlusal loading, and connector widths between tooth- and implant-supported zirconia fixed dental prosthesis.

Background: Few studies have established the relationship between connector widths, cuspal angulation, loading forces, and supporting structures of zirconia fixed dental prosthesis (FDP). The objective of the study was to compare the stress distribution in implant- and tooth-supported zirconia FDP with different connector designs, and cuspal angulations of replaced teeth under diverse angulations of forces. Methods: Finite element (FE) analysis was done by simulating a 3-unit implant- and tooth-supported FDP. FE models with varying cuspal angulations 0°, 20°, and 33° and connector designs 2 mm, 2.5 mm, and 3 mm was generated. The simulated models were loaded with 100 N of forces under different axial and non-axial angulations. The graphical and numerical stresses were observed, recorded, and statistically analyzed. Results: Higher stress of 245.55 MPa in implant-supported FDP and lower stress value of 28.22 MPa in tooth-supported FDP was observed at 0-cuspal inclination for 3 mm connector width. The data were statistically analyzed with unpaired t test to eliminate the differences. The inter-group, intra-group tests, p and t values for various connector, and tooth angulations of tooth- and implant-supported FDP were statistically insignificant. (p > 0.05). Conclusion: There was no statistically significant difference in stress was observed between tooth- and implant-supported FDP for different connector widths, cuspal inclination, and diverse angulation of forces.

The impact of extended pulp chamber preparations on the clinical performance of endocrowns in Indian patients: A 1-year observational study.

Purpose: The limitations of foundation restorations have been reduced with the advent of endocrowns. Despite their success, the extent of endocrowns tooth preparation into the pulp chamber has not been fully explored in the literature. The study aimed to evaluate the clinical performance of endocrowns with 5 mm extended pulp chamber tooth preparations in Indian patients over a 1- year period using modified USPHS criteria. Methods: The observational study recruited 36 participants with definite criteria. Ceramic crown was planned for all the participants. Conventional endocrown tooth preparation was made with 5 mm pulpal extension. Clinical assessments were made at 0-, 6- and 12-months intervals using modified USPHS criteria. The data was statistically analyzed using Friedman test and Wilcoxon signed rank test. Results: One patient (2.8%) experienced loss of retention, marginal adaptation, and loss of anatomical form during 1-year follow up period. The majority of the participants (97.3%) reported no discomfort and high satisfaction. (P < .05) No opposing tooth wear was observed at 0- and 6-months. The results showed statistical significance in the parameters of retention, marginal adaptation, loss of anatomical form, and patient satisfaction. (P < .05). Conclusion: The clinical performance of endocrowns with extended pulp chamber preparation was satisfactory for a period of 12 months.

Comparative evaluation of hemispheric and masticatory laterality in complete dentures with two occlusal schemes - A prospective cohort study.

Purpose: The lateralization can influence the choice of occlusion scheme, patient comfort and success of the prosthesis. The existence of favored masticatory side in complete denture patients and its influence with various occlusal schemes is less analyzed in the literature. The study objective was to compare the masticatory and hemispheric laterality in complete denture subjects rehabilitated with 2 different occlusal schemes at different time intervals. Methodology: The cohort study recruited 26 patients in each group of balanced and non-balanced occlusion with definitive criteria. Conventional procedures were followed in denture fabrication. The hemispheric and masticatory laterality for all participants were established at 0,1,3- and 6-month intervals. The laterality was categorized as preferred chewing side (CPCS), predominant preferred chewing side (PPCS) and observed preferred chewing side (OPCS). The data on chewing side preference was analyzed by chi square test. (α = 0.05). Results: Right side preference was predominant in 86.1% of non-balanced and 60.1% of balanced occlusion participants. The side preference among the 2 laterality and across time interval decreased in masticatory laterality of balanced occlusion participants (P < .05) when compared to non-balanced occlusion. (P > .05). Conclusion: The balanced occlusion dentures had lesser masticatory side preference when compared to non-balanced occlusion complete denture.

Denture tracker for edentulous Alzheimer's patients.

Dementia in Alzheimer's disease complicates the caregivers in tracking the patients. Many options are discussed in the literature. A novel technique is essential to improve the quality of life and to assist in locating the patients. The Global Position System (GPS) trackers are attached to dentures and the movements are observed through a mobile application. This technique discusses on a simple method of tracking Alzheimer's edentulous patients with the support of removable dentures. Denture tracking devices are a secured form of tracking patients. A GPS device in dentures assists in locating the patient's movement and supports the caretakers.

Differences in quality of life and patient satisfaction between complete denture occlusion schemes: A parallel randomized control trial.

STATEMENT OF PROBLEM: Bilateral balanced occlusion has been advocated over nonbalanced occlusion for improved removable complete denture stability and function. However, assessments of quality of life and patient satisfaction studies between the 2 occlusion schemes are lacking. PURPOSE: The objective of this parallel randomized control trial was to determine the difference in quality of life and patient satisfaction between the nonbalanced and bilaterally balanced occlusal schemes. MATERIAL AND METHODS: Sixty participants were included in the parallel randomized control trial of nonbalanced and bilaterally balanced complete dentures. Thirty were recruited into each group with definitive inclusion and exclusion criteria as per the Consolidated Standards of Reporting Trials (CONSORT) guidelines. Quality of life was estimated from the oral health quality of life (Oral Health Impact profile) for edentulous patients questionnaire, and patient satisfaction was analyzed from a visual analog scale. The estimation was made at 0, 3, and 6 months after denture insertion. The data were statistically analyzed with the Friedman, Mann-Whitney, and t test (α=.05). RESULTS: The mean ±standard deviation Oral Health Impact profile score was 60.81 ±8.87 for nonbalanced dentures and 64.12 ±8.98 for bilaterally balanced dentures. The mean ±standard deviation visual analog scale score was 2.84 ±0.28 for nonbalanced dentures and 2.90 ±0.31 for bilaterally balanced dentures. The Mann-Whitney and t test indicated nonsignificant differences between the 2 groups and at different time intervals for Oral Health Impact profile and visual analog scale scores (P>.05). CONCLUSIONS: The study detected no significant differences between the 2 occlusal schemes in quality of life or patient satisfaction.

Estimation of differences and reapplication effect of peel bond strength between silicone-based and water-based adhesives.

STATEMENT OF PROBLEM: Retention is essential for maxillofacial prosthesis. Adhesives are commonly used for retention because of their simplicity, availability, and cost-effectiveness. Studies that have estimated the differences in bond strength between the types of adhesives and the impact of reapplication are sparse. PURPOSE: The purpose of this observational clinical study was to estimate the peel bond strength and reapplication effects of water-based and silicone-based adhesives at 0, 24, and 48 hours. MATERIAL AND METHODS: A total of 46 participants were enrolled, with 23 participants in each adhesive test group-water-based and silicone-based adhesive. Silicone elastomeric strips were attached to the ventral aspect of the participants' forearm 5 cm away from the radial styloid prominence. The strength of each adhesive group was tested at 0 hours, and its reapplication effects were evaluated at 24 and 48 hours. The peel bond strength was estimated by using a universal testing machine, and the data were recorded in N/m and statistically analyzed by the independent Student t test and Spearman rho correlation coefficient tests (α=.05). RESULTS: The mean ±standard deviation of peel bond strength at 0 hours for silicone-based adhesive (111.5 ±2.5 N/m) was higher than that for water-based adhesive (99.9 ±3.9 N/m) (P<.001). On reapplication, the silicone-based adhesive had a higher peel bond strength (113.5 ±2.8 N/m) than the water-based adhesive (105.2 ±3.0 N/m) (P<.001). The results were statistically significant between the 2 groups at different time intervals (P=.04). CONCLUSIONS: The mean peel bond strength of the silicone-based adhesive was higher than that of the water-based adhesive. The reapplication of adhesives improved the bond strength in both the groups.

Mechanical properties and surface roughness of chitosan reinforced heat polymerized denture base resin.

PURPOSE: The antifungal property of chitosan (Ch) in denture base resin (DBR) was well established. Ch influence on the mechanical properties of DBR is less studied in the literature and is vital for clinical success of denture. This study estimates the effect of different concentrations of Ch on the flexural strength (FS), fracture toughness (FT), impact strength (IS) and surface roughness (Ra) in heat polymerized DBR. METHODS: A total of 160 samples were divided into 4 groups (n =10) by weight percentage - Ch 0, Ch 5, Ch 10, Ch 15. FS and FT were estimated by three-point bending test. IS was determined by Charpy test. Ra was evaluated by non-contact laser surface profilometer. The tested samples were characterized by scanning electron microscope and Fourier transformation infra-red spectroscopy. Data were statistical analyzed with one-way ANOVA and Post hoc Bonferroni test. RESULTS: FS, FT and IS improved with Ch addition when compared to control group. Ch5 showed higher "FS, FT, IS. (p<0.001)". Increased Ra was observed in Ch5 and Ch10 with significant statistical differences among the groups. (p <0.001) Ch15 displayed decrease in Ra compared to control group. CONCLUSION: The addition of Ch to DBR improved the "FS, FT, IS at 5%wt and Ra at 15%wt" of Ch.

Retention of removable complete dentures made with different posterior palatal seal techniques and oral health quality of life: A clinical study.

STATEMENT OF PROBLEM: How different methods of recording posterior palatal seal affect removable complete-denture retention and oral health quality of life is unclear. PURPOSE: The purpose of this clinical study was to compare the retention and oral health quality of life (OHIP-14) between conventional and arbitrary posterior palatal seal techniques in participants with removable complete dentures. MATERIAL AND METHODS: Edentulous patients were recruited according to definitive criteria. The participants were randomly divided into conventional and arbitrary seal. After the delivery of the denture, the retention was evaluated with a force gauge dynamometer and at 3, 6, 9, and 12 months. Denture satisfaction was evaluated with the OHIP-14 questionnaire. Data were statistically analyzed by using the t test and repeated measure ANOVA (α=.05). RESULTS: The mean ±standard deviation values (N) for conventional seal at 0, 3, 6, 9, and 12 months by dynamometer in the anterior region ranged from 4.73 ±0.78 to 4.90 ±0.81 and in the posterior region between 5.07 ±0.84 and 5.31 ±0.99. Dynamometer values for arbitrary seal in the anterior region were from 4.56 ±0.77 to 4.88 ±0.81, and in the posterior, it varied between 4.74 ±0.74 and 5.15 ±0.81. Force gauge values (N) for conventional and arbitrary seal were in the range of 18.35 ±2.84 to 20.69 ±3.89. The general mean ±SD OHIP-14 was higher for the conventional seal at 3.12 ±0.25 than for the arbitrary seal at 2.73 ±0.23 The difference between the conventional and arbitrary seal techniques was not statistically significant (P>.05) CONCLUSIONS: No significant difference in complete denture retention was detected between the 2 posterior palatal seal techniques. Oral health quality of life was higher with the conventional seal technique.

Evaluation of Psychological Stress Marker in Partially Edentulous Indian Adults Restored with Fixed Dental Prosthesis - A Prospective Cohort Study.

BACKGROUND: Clinical studies have established mastication as a stress relaxation behavior in humans. Absence of teeth compromises mastication, increasing psychologic stress in individuals depicted by many physiologic changes in body. Quantitative level of psychologic stress bio-markers serve as indicators of underlying physical ailment. Lesser literatures are available in determining the role of alpha amylase stress bio marker in partially edentulous clinical situations. AIM: The purpose of this clinical study was to evaluate the levels of salivary alpha-amylase (sAA) stress biomarker in partially edentulous subjects before and after restoration with fixed dental prosthesis. MATERIAL AND METHODS: Forty partially edentulous patients with missing mandibular first molar were selected for this study. Two questionnaires, state trait anxiety inventory (STAI) and perceived stress scale (PSS) was used to evaluate stress and anxiety levels of participants. The recruited participants were treated with metal ceramic fixed dental prosthesis (FDP). A visual analog scale (VAS) was used to determine the patient satisfaction .Unstimulated salivary samples were collected preoperative, 3rd and 6th month post FDP placement. Level of sAA was estimated. Data obtained in the form of mean ± SD was subjected to statistical analysis using paired sample t-test (α=.05). RESULTS: The salivary alpha amylase level was highest with mean of 36.73 µM/min/mg ptn before restoration with FDP. In the third month after prosthesis placement, the enzyme values decreased to16.62 µM/min/mg ptn and least value of 8.58 µM/min/mg ptn was detected in sixth month (P < 0.05). CONCLUSION: The salivary alpha amylase stress biomarker decreased after tooth replacement with FDP.

Clinical acceptability of PEEK fixed dental prosthesis in partially edentulous patient - A one year single arm pilot study.

PURPOSE: The study evaluated the clinical efficacy of Polyether ether ketone (PEEK) fixed dental prosthesis (FDP) over a period of one year using modified Ryges criteria and California Dental Assessment system. METHODS: The group consisted of 20 patients restored with posterior three-unit PEEK FDP. Patient recall and clinical examination of the restorations were done at interval of 0, 3, 6, 9 and 12 months. Clinical examination for evaluation of longevity of restorations was done using modified Ryges criteria and California dental assessment system on chipping of the veneered composite, discoloration at the marginal areas, and marginal adaptation, retention, periodontal health and hygiene of PEEK FDP. Radiographic assessment was done after 12 months. Statistical analysis were done using Friedman test. RESULTS: 95% of the patients had maintained the restoration of PEEK FDP without fracture during the study period. 5% patient reported with de-cementation of fixed dental prosthesis. 10% of the PEEK FDP shows marginal discoloration. However, no significant changes were observed during the periodic time interval evaluation in marginal adaptation, oral hygiene status and periodontal health. (p < 0.5). CONCLUSION: PEEK FDP had satisfactory clinical efficacy and acceptable clinical outcome during the observation period of 12 months. No significant radiological changes were observed at the end of 12 months.

Effects of incorporation of silver and titanium nanoparticles on feldspathic ceramic toughness.

Background. Porcelain is brittle and in many situations it requires replacement in fractured or chipped restorations. The prospects exist in improving the strength of feldspathic porcelain to widen its applications. This study evaluated the fracture toughness of feldspathic porcelain after incorporation of silver and titanium nanoparticles at varying concentrations (0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%). Methods. Test specimen dimensions were standardized to ASTM C1421-16 standards and a three-point flexure test was carried out to evaluate fracture toughness. A total of 330 samples were fabricated and broadly divided into three groups. Group I (titanium nanoparticles) and group II (silver nanoparticles) were further subdivided into 5 groups (0 wt%, 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%) for fracture toughness analysis, with each group consisting of 30 samples. Group III contained the superior concentration of both titanium and silver nanoparticles. The fracture toughness (KIC) was calculated using indentation fracture method and microstructure observations were made using scanning electron microscopy. The KIC values were compared and evaluated using one-way ANOVA. Results. Data were analyzed using one-way ANOVA and Tukey's HSD post hoc test multiple comparisons. The mean values of group I, group II and group III were 1.949 MPa.m1/2, 2.002 MPa.m1/2 and 1.330 MPa.m1/2 , respectively. Conclusion. The results revealed that the samples reinforced with titanium and silver nanoparticles showed significant increases in fracture toughness. The blending of superior concentration of both titanium and silver nanoparticles decreased fracture resistance.

A salivary sensor for the management of xerostomia in edentulous patients.

This article describes a method for managing xerostomia in edentulous patients with a newly developed salivary sensor. A micropressure sensor unit with a capsule to hold artificial salivary substitute was built into the dental prosthesis. This sensor prosthesis can help patients overcome mouth dryness, improves patient comfort, and aids in retention of the prosthesis.

Correlation between iris diameter and the width of the maxillary central incisor with digital image analysis.

STATEMENT OF PROBLEM: Various methods have been suggested for determining the width of maxillary anterior teeth for complete dentures. A straightforward and reliable technique for anterior tooth selection in complete denture is still needed. PURPOSE: The purpose of this clinical study was to determine the correlation between the horizontal visible iris diameter (HVID) of the eye and the mesiodistal width of the maxillary central incisor tooth in a dentate Indian population. MATERIAL AND METHODS: One hundred Indian dental students participated in this study. A standardized image of the face revealing the eyes and teeth on smile was captured. The measurements of the HVID and the mesiodistal width of the maxillary central incisor at the cervical third, middle third, and incisal edge were evaluated with photoimaging software. The data were subjected to statistical analysis by paired-sample t test to compare the right and left sides, independent-sample t tests to compare between sexes, and the Pearson correlation coefficient (r) to investigate the association between variables (α=.05) RESULTS: A positive correlation between the HVID and the mesiodistal width of the maxillary central incisor was found in men, with r values of .62, .78, and .79 in the cervical, middle, and incisal third regions, respectively. In women, respective r values of .59, .73, and .75 were found. Minimal differences were observed between right- and left-side measurements. CONCLUSIONS: The HVID of the eyes can be used to estimate the mesiodistal width of the maxillary central incisor tooth.

Golden proportion assessment between maxillary and mandibular teeth on Indian population.

PURPOSE: This study evaluated the existence of golden proportion between the widths of the maxillary and mandibular anterior teeth in Indian population. MATERIALS AND METHODS: The clinical tooth width measurements were recorded with the digital vernier calipers on 576 patients of both sexes in the age group of 21 - 30 years. Flexible ruler was used to determine the width of maxillary and mandibular anterior teeth on the patients by the same operator. The data obtained was statistically analyzed using paired student t-test (α=.05). RESULTS: The golden proportion was not found between the width of the right central and lateral incisors in 53% of women and 47% of men. The results revealed the golden percentage was rather inconstant in terms of relative tooth width. CONCLUSION: The golden proportion is an inappropriate method to relate the successive widths of the maxillary anterior teeth in Indian population.