Temporary Crowns Research Articles

Dynamics of soft tissue thickness in the area of one-stage dental implantation with the use of a soft tissue cuff reinforced with bone graft material

Aim. The study aims to compare the dynamics of the increase in the thickness of soft tissues in the area of one-stage dental implantation after the use of a xenogenic collagen matrix and a soft tissue cuff reinforced with bone graft material (BGM). Materials and methods. The study enrolled 51 patients who received one-stage dental implantation. Depending on the dental implantation technique, the patients were divided into two groups. The main group comprised 25 patients who after teeth extraction had their implants placed into a prepared socket preliminary filled with Sensobone xenograft, after which BGM was formed with the subsequent fixation of a temporary crown. The comparison group included 26 patients who after teeth extraction had their implants placed into a prepared socket preliminary filled with Sensobone xenograft, after which the soft tissue area was filled with Senobone xenograft, with the subsequent fixation of the temporary crown. The attached mucous membrane (AMM) thickness around the implant was measured before implantation and again after 3 months and one year (the distance from the top of the alveolar ridge center to the middle of the muco-gingival junction in the vestibular direction was measured with a periodontal probe). The results of the study were processed on a PC using the statistical package of the licensed software Statistica 13.0 (Copyright 1984–2018 TIBCO Software Inc. All rights reserved. License No. JPZ804I382130ARCN10-J). Results. The thickness of the AMM around the one-stage dental implantation area before implantation and in the dynamics did not depend on the jaw in both groups. Before implantation, the lowest values of the AMM thickness in patients of both groups were registered in the area of the canine and the first molar. The AMM thickness did not depend on the age and sex of the patients, as well as on the type of teeth and jaws. The use of BGM in one-stage dental implantation provided a significant increase in the AMM thickness by 1.38 mm in 3 months after implantation, and by 1.45 mm in a year (the intergroup difference was 0.29 mm in 3 months and 0.32 mm in a year), and a significant increase in the AMM thickness on both jaws, by 1.36 mm on the upper jaw and 1.41 mm on the lower jaw in 3 months and by 1.44 mm on the upper jaw and by 1.5 mm on the lower jaw in a year (the intergroup difference was 0.32 mm on the upper jaw and 0.33 mm on the lower jaw in a year) as well as a significant increase in the AMM thickness in all teeth after a year of follow-up. There were no dental implant failures in both groups, and the survival rate of implants was 100 % one year after the placement. Conclusions. The effectiveness of one-stage dental implantation is facilitated by the adequate AMM thickness provided by BGM.

Analysis of the efficacy of two kinds of loss restoration of posterior teeth using 3D printing temporary crown during the second phase of implant surgery.

This study aimed to analyze the effect of 3D printing temporary crowns on the single and continuous loss restoration of posterior teeth during secondary implant surgery. This study adopted a single-center, randomized, single-blind, parallel-controlled trial design. Thirty patients who were admitted to the Department of Stomatology, Affiliated Hospital of Jiangnan University between January 2020 and February 2023 and who had >2 consecutive missing posterior teeth were implanted with the same implant system. A simple random method was adopted to assign 30 patients to group A (using 3D-printed temporary crowns) and group B (control group) in a 1:1 ratio, with 15 patients in each group. The final prosthesis in Experimental group A was done based on the adjustment of the temporary crown and tooth. Both groups were compared based on total time, accuracy, and patient satisfaction of the final prosthesis. Additionally, 30 patients who had undergone single posterior tooth implantation during the same period were selected as the study objects and divided into 2 groups using the random comparison table method. The patients in the experimental group C (15 cases) were provided with 3D-printed temporary crowns, and the other 15 patients were assigned to the control group D (15 cases). In the experimental group A, the total time spent on dentures was 10.1 ± 1.3 minutes, which was lesser compared with that spent in the control group B (P < .05). Experimental group A exhibited a significantly higher accuracy of prosthesis (P < .05), as well as significantly higher satisfaction of patients (P < .05). Regarding the food impaction rate, after formal implantation and restoration, the food impaction rate of the experimental group C at 1 month and 6 months was compared with that of the traditional 2-stage surgery group D. Three-dimensional printing temporary crowns exhibited significantly better therapeutic effects for restoration in patients with continuous missing implants in posterior teeth. 3D printing temporary crowns in patients with single posterior tooth implant restoration showed promising results, which improved food immobilization and actively and effectively reduced the complications associated with a single posterior tooth implant.

Flexural Strength of Different Commercially Available Auto-Polymerizing Acrylic Resins: An In Vitro Study.

Background Auto-polymerizing acrylic resins, composed primarily of poly(methyl methacrylate) and methyl methacrylate, are crucial in prosthetic dentistry due to their ease of use, cost-effectiveness, and acceptable aesthetics, polymerizing at room temperature to form solid polymer networks. One of the most important mechanical properties of these resins is flexural strength, which is essential for their performance under continuous masticatory forces. In clinical applications, prosthetic materials endure repetitive stress from chewing, and resins with higher flexural strength are better equipped to resist deformation and fractures. This property is vital for ensuring the long-term integrity of prostheses, minimizing the risk of material failure, and enhancing prosthetic longevity, thus contributing to better clinical outcomes and patient satisfaction. Objective Resins with superior flexural strength, such as DPI, provide better clinical outcomes. High flexural strength minimizes the risk of material failure in high-stress areas, especially in extensive restorations like temporary bridges or denture repairs. For clinicians, using materials with greater strength reduces the likelihood of restoration failure, ensuring more reliable performance and fewer interventions for repair or replacement. This study aims to evaluate and compare the flexural strength of three commercially available auto-polymerizing acrylic resins, Pyrax (Pyrax International, Uttarakhand, India), DPI (Dental Products of India, Mumbai, India), and Quick Ashvin (National Dental Supply Company, Delhi, India), to determine their suitability for various dental applications. Methodology Following American Dental Association specifications, 20 rectangular bar-shaped specimens (25 mm x 2 mm x 2 mm) of each resin type were prepared. The resins were mixed according to manufacturer instructions, poured into molds, and allowed to auto-polymerize at room temperature. Post-polymerization, specimens were immersed in artificial saliva at 37°C for 10 days to simulate oral conditions. Flexural strength was assessed using a three-point bending test on a universal testing machine, and results were analyzed using ANOVA and post-hoc Bonferroni tests. Results The flexural strength of DPI resin bars (mean=482.10 MPa, SD=17.28) was significantly higher compared to both Pyrax (mean=467.82 MPa, SD=15.01) and Quick Ashvin (mean=470.17 MPa, SD=8.18). ANOVA revealed a significant difference among the resins (F=5.956, p=0.004). Post-hoc Bonferroni comparisons showed a statistically highly significant difference between DPI and Pyrax (p=0.006) and a significant difference between DPI and Quick Ashvin (p=0.028). No significant difference was observed between Pyrax and Quick Ashvin (p=1.000). Conclusion DPI resin, with its superior flexural strength, is the best choice for high-stress dental applications, while Quick Ashvin offers balanced performance for interim uses such as temporary crowns. Pyrax, being more cost-effective, is suitable for less demanding cases. This study underscores the importance of selecting materials based on mechanical properties and calls for further research to enhance resin durability. For dental practitioners, DPI is ideal for long-lasting restorations, Quick Ashvin for temporary solutions, and Pyrax for budget-conscious cases.

Importance of an Evaluation Phase When Increasing the Occlusal Vertical Dimension: A Systematic Review.

To assess whether an evaluation period is necessary for patient and clinical success when increasing the occlusal vertical dimension (OVD) for a full mouth rehabilitation. A systematic search was conducted in six databases: MEDLINE, Web of Science, Scopus, CENTRAL, VHL, and EMBASE. The eligibility criteria of this systematic review used the PICO framework to address the following research question: "In dentate adults requiring an increase in occlusal vertical dimension (OVD) (P), is an evaluation period of the new OVD (I) superior to no evaluation period (C) in terms of success (O)?" Study characteristics, survival, and success rates were extracted from each article. No language restrictions were applied. Study quality was appraised using Cochrane's Risk of Bias 2 tool and Newcastle-Ottawa Scale (NOS) according to the study design. The electronic search yielded 1188 titles after duplicates were removed. One RCT and 103 non-comparative articles were found relevant to the search question. Out of the 103 articles, 80 had an evaluation phase and 23 did not. The included RCT revealed that removable devices tended to cause chewing difficulties, unclear speech, and esthetic discomfort. Therefore, the use of a removable appliance to functionally or esthetically evaluate OVD was not indicated prior to the definitive treatment. Esthetics was the highest reported parameter preoperatively for the non-comparative studies, at 85% with an evaluation and 86% without. At present, there is lack of evidence that an evaluation period improves clinical and patient-reported outcomes when increasing OVD for full mouth rehabilitations. Thus, an increase in OVD can be successful with or without an evaluation phase. The evaluation phase helps the clinician manage patient expectations and assist with the treatment sequencing. This phase is most effective with fixed restoration, such as temporary crowns or adhesive restorations. However, there is limited evidence that this phase improves clinical or patient-reported outcomes.

One-Piece Versus Two-Piece Abutments for Single Crowns in the Esthetic Zone: A Clinical Trial.

To evaluate whether a two-piece abutment is equivalent to a one-piece in peri-implant esthetics, patients' satisfaction, and oral health-related quality of life (OHRQOL) for implant-supported anterior single crown placement. Thirty implants were allocated sequentially: 15 in the one-piece abutment group (OP) and 15 in the two-piece abutment group (TP). Peri-implant esthetics were evaluated by the pink esthetic score (PES) at temporary crown insertion (T1), after tissue conditioning (T2), and at 30 days after the final crown insertion (T3). OHRQOL was measured using the OHIP-14 and satisfaction was evaluated using the visual analog scale (VAS) at baseline, T1, and T3. Treatment was considered equivalent if the 95% coefficient interval (CI) for mean difference in PES was between -1.5 and +1.5 points. Statistical analysis was performed using Mann-Whitney, SPANOVA, and Student's t-test, with Sidak's posttest, adopting p < 0.05. No differences were found between the groups for any variable and during follow-up. A significant increase in OHRQOL and satisfaction was observed at T3, when compared to baseline (p < 0.05) for both groups. Significant improvements in peri-implant esthetics were also observed throughout the treatment, particularly after tissue conditioning (p < 0.05). Primary and secondary outcomes were evaluated for equivalence, and both abutment types were considered equivalent following the insertion of the temporary crowns. Two-piece abutment was equivalent to one-piece abutment for peri-implant esthetics, quality of life, or the satisfaction of patients rehabilitated with metal-free single crowns. Tissue conditioning and final crown insertion appear to play a role in improving these outcomes.

Mechanical and Physical Properties of 3D Printed Temporary Crowns

Mechanical and Physical Properties of 3D Printed Temporary Crowns

Surface Roughness and Bacterial Adhesion of Temporary Crown Materials

Surface Roughness and Bacterial Adhesion of Temporary Crown Materials

Repair bond strength of 3D printed temporary crown materials

Repair bond strength of 3D printed temporary crown materials

Analyzing the Educational Needs of Dental Hygiene Students Using the Borich Needs Assessment and Locus for Focus Models

Objective: This study aimed to develop a standard for a practice-based curriculum that reflects the needs of dental hygiene students’ clinical practice education and to provide basic data that can contribute to improving dental hygienists’ competence in clinical practice. Methods: A survey of 132 dental hygiene students from selected universities was conducted. The Borich Needs Assessment model and The Locus for Focus models were used to evaluate the students’ educational needs for clinical practice content. Results: The highest level of present educational needs was for ‘fluoride application,’ while the greatest requirement was for ‘preparing surgical dental treatment’. Using The Locus for Focus model, 33 items in the first quadrant were identified as common to the Borich Needs Assessment priorities. These items include ‘dental insurance claims’, ‘patient reception’, ‘dental materials counseling’, ‘making a temporary crown’, ‘setting a temporary crown’, ‘document management’ and ‘prepare of dental emergencies’. Conclusions: The analysis of the clinical practice needs of dental hygiene students identified the needs for practice-oriented education. These findings suggest that future curriculum revisions should reflect not only the needs of students, but also the perspectives of educators and clinical dental hygienists.

Manufacturing of temporary artificial crowns using 3D printing

The article discusses current issues of introducing digital technologies in orthopedic dentistry and the feasibility of using them to improve the quality of dental care and reduce labor costs. Object: to develop guidelines for the use of temporary composite crowns using 3D printing, to identify the advantages of this method compared to traditional methods of manufacturing orthopedic dental structures of this type. Material and methods. Based on the author’s clinical experience in the dental clinic of the Clinical Hospital “RZhD-Medicine”, Chelyabinsk, 72 clinical cases were analyzed (patients aged 18 to 55 years, 50% men, 50% women), of which in 36 cases composite crowns were made for patients using 3D printing in accordance with patent No. 2805832, and in 36 cases – in the traditional way. Results and discussion. Recommendations are given for the practical application of the method proposed by the author for the production of temporary composite crowns using 3D printing, and the advantages of this method compared to traditional crown production are shown. Conclusions. It is concluded that the use of the technology for producing temporary composite crowns using 3D printing improves the quality of services and increases economic efficiency: the process of taking impressions occurs without an impression mass, physical labor is facilitated, the production time is reduced, and therefore the number of visits, the amount of consumables is reduced; the accuracy of 3D structures for temporary use increases, there is no release of residual monomer onto the oral mucosa, which is typical for the production of temporary structures from acrylic plastics.

Cumulative effect of digital manufacturing techniques, preparation taper and finish line designs on the retention of aged temporary molar crowns − An in vitro study

ObjectiveThis study evaluated the effects of finish-line design, tooth preparation taper or total occlusal convergence (TOC), and digital production technology on the retention of provisional crowns for molars. Material and MethodsDifferent taper angles (10° TOC and 20° TOC) and finish line designs (chamfer and shoulder) were used to prepare four mandibular first molar teeth. Two subgroups of the prepared teeth received temporary crowns that were either “Computer-Aided Design” and “Computer-Aided Manufacturing (CAD/CAM) milled or 3D printed. Hence, eight test groups of temporary crowns containing 10 samples each were created. Groups 1–4 were milled, and Groups 5–8 were 3D printed specimens. A consistent procedure was used to cement 80 temporary crowns. The specimens were thermocycled for a total of 5000 heat cycles, initially at 5 °C for 30 s (dwell time) and then at 55 °C for 30 s. The pull-off force necessary to remove the temporary crowns was recorded, and the tensile strength, which served as the dependent variable, was calculated. Analysis of variance (ANOVA) was used to assess the variations in retention forces among the test groups. ResultsThe mean tensile strengths at maximum load [MPa] were higher in Groups 5, 6, 7, 8 (6.6 MPa, 6.91 MPa, 7.65 MPa, and 7.45 MPa respectively) as compared to the mean tensile strengths at maximum load [MPa] in Groups 1, 2, 3, 4 (2.35 MPa, 3.52 MPa, 3.21 MPa, and 2.45 MPa respectively). ConclusionFor extended periods, 3D-printed crowns with steeper preparation tapers (20° TOC) and shoulder finish lines exhibited enhanced retention.

Clinical assessment of monolithic zirconia crowns fabricated using an intraoral scanner.

This in vivo study assessed the accuracy of single-tooth monolithic zirconia crowns made using an intraoral scanner (IOS) and computer-aided design/computer-aided manufacturing (CAD/CAM) technology. Thirty patients requiring single posterior crowns were selected. The teeth were prepared with a deep chamfer finish line with a 1-mm extension subgingivally and a 1-mm reduction in all surfaces by one prosthodontist. The gingival margins were retracted using a gingival retraction paste before making impressions using a Trios scanner. All the digital impression files were sent to one laboratory using the dental designer software (3Shape, Copenhagen, Denmark). After completing the milling and sintering processes, the crowns were dyed and glazed. After removing the temporary crown, the qualitative assessment of proximal contacts of definitive monolithic zirconia crowns was performed according to the CDA criteria. Data were analyzed with Friedman's two-way analysis and independent t-test at α=0.05. The difference in axial and total gaps between premolar and molar teeth was not significant; however, the mean marginal gap of molars was higher than that of the premolars (P=0.043). Furthermore, the comparison of the axial, total, and marginal gaps between the upper and lower jaws showed no significant difference (P>0.05). The distribution of occlusal and proximal contacts indicated 60% and 66.7% proper contacts and no contacts in 6.7% and 10% of cases, respectively. Using IOSs could result in accurate monolithic zirconia crowns in terms of adaptation. Also, most occlusal and proximal contacts did not need any adjustments.

Influence of the Composition of Provisional Luting Materials on the Bond Strength of Temporary Single-Tooth Crowns on Titanium Abutments.

In addition to zinc oxide-based cements, resin-based materials are also available for temporary cementation. The aim of this in vitro study was to determine the influence of the different material compositions on temporary bonds. In nine test series (n = 30), temporary bis-acrylate single-tooth crowns were bonded onto prefabricated titanium abutments with nine different temporary luting materials. After simulating an initial (24 h, distilled water, 37 °C), a short-term (7 days, distilled water, 37 °C) and a long-term provisional restoration period (12h, distilled water, 37 °C; thermocycling: 5000 cycles) in subgroups (n = 10), the bond strength was examined using a combined tensile-shear test. Statistical analysis was performed by univariate analysis of variance or a non-parametric Kruskal-Wallis test, followed by post hoc tests. Of the three resin-based materials, two showed significantly higher bond strength values compared to all other materials (p < 0.001), regardless of the storage procedure. The resin-based materials were followed by eugenol-free and eugenol-containing zinc oxide materials. Significant intragroup differences were observed between the composite-based materials after all storage periods. This was only observed for some of the zinc oxide-based materials. The results show that under in vitro conditions, not only the composition of the temporary luting materials but also the different storage conditions have a significant influence on temporary bonds.

A prosthetic-surgical approach for aesthetic treatment of peri-implant soft tissue defects: A case report

Peri-implant soft tissue defects (PSTD) in the esthetic zone affect approximately 54% cases of post-implant insertion, leading to aesthetic concerns and increasing the risk of peri-implantitis. Various surgical techniques are aimed at addressing these issues, but the outcomes can be unpredictable, especially for severely mispositioned implants. This report details a combined prosthetic and surgical approach to treat a severely angulated single central maxillary implant with mid-labial mucosal recession. A 38-year-old female expressed dissatisfaction with the implant at 21 area, which appeared elongated due to peri-implant mucosal recession of almost 4 mm. Treatment involved two phases: 1) prosthetic phase involves replacing the original crown of implant at 21 area with a temporary crown to promote mucosal growth and 2) surgical phase that involves soft tissue surgery three months later using an envelope flap technique at the recipient site and a connective tissue graft harvested from the palate. Upon three months after the surgery, full coverage with thick mucosal tissue was achieved, and a new zirconia crown was placed. The outcome remained stable throughout the nine-month follow-up. This case demonstrates that PSTD in angulated implants in the esthetic zone can be effectively treated through a combination of prosthetic and surgical modalities.

A retrospective cohort study on 3D printed temporary crowns

In this retrospective cohort study the survival rate, clinical parameters, patient satisfaction with aesthetics and oral health-related quality of life of 3D printed temporary crowns were evaluated. Temporary crowns were 3D printed with a Form3B out of Permanent Crown Resin (Formlabs GmbH). Anonymized data for the restorations’ survival (in-situ) was evaluated retrospectively for 98 temporary crowns of 63 patients fabricated within 19 months. Among these restorations, further analysis was conducted for 42 temporary crowns of 24 patients regarding clinical parameters (modified USPHS criteria), patient satisfaction with aesthetics and impact on oral health-related quality of life (OHRQoL) (OHIP 14). Descriptive statistical analysis (significance level of α = 0.05) included a Kaplan–Meier curve for survival analysis, a Kolmogorov–Smirnov test for USPHS, aesthetics and OHIP data, followed by a Wilcoxon test for USPHS and OHIP data and Chi-squared test for aesthetics data. Cronbach’s alpha was calculated for OHIP data. The average observation period for survival analysis was 256 days. The survival rate was satisfactory at 98% and n = 2 catastrophic failures (i.e. fracture) occurred. Total OHIP scores, with good reliabilities, improved from 6.63 to 2.21 significantly (p = 0.005) and patient satisfaction with aesthetics (p < 0.001) as well. Clinical analysis with modified USPHS criteria revealed encouraging results.

An In Vitro Evaluation of Periotest Implant Stability Measurements Taken on Implant Retained Crowns and Healing Abutments.

To assess the reliability of implant stability measurements recorded with the Periotest device and to investigate the differences in values when these measurements were taken on implant retained crowns and healing abutments. Fifty-six implants in eight synthetic bone blocks were used to carry out implant stability measurements using the Periotest device by two different operators. Each block constituted an example of bone of density D1, D2, D3, or D4, and two blocks of each density were used. The healing abutments placed were of a height to allow approximately 6 mm of the implant-abutment complex to be supracrestal and temporary crowns were made to match the dimensions of an average central incisor. Descriptive statistics were used to describe the perio test values (PTVs) at each of the different heights on the implant abutments and implant crowns. Means for each site were calculated and distribution of data assessed using the Kruskal Wallis test. The interclass correlation coefficient (ICC) was used to determine the relationship between the PTVs recorded on the implant abutments and implant crowns. The mean PTV (±standard devidation) recorded across all sites was 5.57 ± 11.643 on the implant abutments, and 12.27 ± 11.735 on the temporary crowns. Excellent/good inter-operator ICCs were recorded for the mid-abutment site in all bone blocks D1-D4 (ICC = 0.814, p < 0.001, ICC = 0.922, p < 0.001, ICC = 0.938, p < 0.001, ICC = 776, p < 0.001). For mid crown sites, ICC between operators was excellent/good only for recordings in D2 bone (ICC = 0.897, p < 0.001). Periotest device seems to be able to reliably measure implant stability across all types of bones when the implant stability is assessed at approximately 3 mm coronal to the implant platform for abutments and 4.5 mm for implant supported single crowns.

ИСПОЛЬЗОВАНИЕ ЦИФРОВЫХ ТЕХНОЛОГИЙ ПРИ РЕАБИЛИТАЦИИ ПАЦИЕНТОВ С ПЕРВИЧНОЙ АДЕНТИЕЙ

Abstract. Introduction. Number of patients with hypodontia has increased at orthodontic appointments. According to different authors, the frequency of tooth rudiments absence ranges from 2 % to 16.5 %. The highest rank is held by maxillary lateral incisors hypodontia. Due the increased patients’ aesthetic requirements, it is a difficult task, especially with the alveolar ridge bone deficiency. Treatment of such patients requires a multidisciplinary approach and the use of digital technology. The aim of the study is to improve the treatment effectiveness for patients with hypodontia, using digital planning, surgical templates, intraoral scanning, and the CAD/CAM modelling of metal-free screw-retained crowns on dental implants. Materials and Methods. The clinical study was performed in the dental office PreziDent (Cheboksary) in 2018-2023. The total number of patients was 24 people (female), aged 16 to 34 years. There were two groups (n=12). The first group patients had their missing teeth replaced using dental implantation without using any digital technology. In the second group, those with the use of digital technologies. Gingival condition of the dentition defect area was assessed: Severity of stippling phenomenon degree, density gingival margin adherence to the structural materials, vacuum capillary resistance by Kulazhenko, and Mülleman-Cowell bleeding index. SPSS 13.0 software package was used for the statistical processing of the results obtained. Results and Discussion. The first stage of treatment included orthodontic treatment, bracket placement and canine distalization. Some patients were fitted with orthodontic miniscrews in the subclavicular region. After creating gaps for the future lateral incisors, a surgical template was fabricated and dental implants were placed. Four months after implantation, the bracket system was removed and the implant temporary crowns were placed; six months later, CAD/CAM digital metal-free prosthetics were placed. Not a single case of implant loss was detected. An algorithm framework was developed for managing patients with maxillary lateral incisor hypodontia. Conclusions. Using computer programs for planning dental implantation and in navigation surgery allows installing dental implants most accurately and making digital metal-free prosthetic constructions by computer-aided modelling and manufacturing. Thus, the risk of complications is reduced and an effective functional and aesthetic state of dentoalveolar system is achieved in patients with primary anodontia.

Investigating the impact of post-curing cycles on surface hardness and color stability in 3D printed resin crowns.

This study evaluated the effect of different post-curing cycles on the Vickers hardness, color change, and translucency value of 3D printed methacrylic acid ester-based temporary and permanent crown resins. A total of 300 samples were printed in disk shape (ø:8mm, thickness: 2mm) using VarseoSmile Crown Plus (VSC) and VarseoSmile Temp (VST) materials from a 3D printer. These disks were divided into five subgroups (n = 30 each) based on flash-curing cycles (0, 750, 1500, 2250, and 3000). Surface hardness tests and color tests were conducted on both the green state and flash-cured groups. The data were analyzed using univariate analysis of variance (ANOVA). The hardness of 3D printed temporary and permanent crown resin increased with post-curing time. Compared to the post-curing cycle recommended by the manufacturer, no clinically significant color change (ΔE00 ≥ 2.25) was observed in any of the polymerized groups. It was determined that permanent crown material had a more translucent structure than temporary crown material. The interaction between material and post-curing had significant effects on surface hardness, color (ΔE00), and translucency of 3D printed methacrylic acid ester-based resins.

Effects of washing agents on the mechanical and biocompatibility properties of water-washable 3D printing crown and bridge resin

Three-dimensional (3D) printing, otherwise known as additive manufacturing in a non-technical context, is becoming increasingly popular in the field of dentistry. As an essential step in the 3D printing process, postwashing with organic solvents can damage the printed resin polymer and possibly pose a risk to human health. The development of water-washable dental resins means that water can be used as a washing agent. However, the effects of washing agents and washing times on the mechanical and biocompatibility properties of water-washable resins remain unclear. This study investigated the impact of different washing agents (water, detergent, and alcohol) and washing time points (5, 10, 20, and 30 min) on the flexural strength, Vickers hardness, surface characterization, degree of conversion, biocompatibility, and monomer elution of 3D printed samples. Using water for long-term washing better preserved the mechanical properties, caused a smooth surface, and improved the degree of conversion, with 20 min of washing with water achieving the same biological performance as organic solvents. Water is an applicable agent option for washing the 3D printing water-washable temporary crown and bridge resin in the postwashing process. This advancement facilitates the development of other water-washable intraoral resins and the optimization of clinical standard washing guidelines.

A comparative study of the use of digital technology in the anterior smile experience

Objectivesthis study aims to compare the clinical outcomes of traditional and digital crown extension guides in the aesthetic restoration of anterior teeth. Additionally, the study will analyze the differences in the results of various digital crown extension guides in anterior aesthetic restorations.MethodsSixty-two patients who required aesthetic restoration of their anterior teeth were selected for this study. The patients had a total of 230 anterior teeth and were randomly divided into three groups: a control group of 22 cases who received diagnostic wax-up with pressure film, an experimental group 1 of 20 cases who received 3D printed digital models with pressure film, and an experimental group 2 of 20 patients who received digital dual-positioning guides. The control group had a total of 84 anterior teeth, experimental group 1 had 72 anterior teeth, and experimental group 2 had 74 anterior teeth. The study compared three methods for fabricating crown extension guides: the control group used the diagnostic wax-up plus compression film method, while experimental group 1 used compression film on 3D printed models and experimental group 2 used 3D printed digital dual-positioning crown extension guides. After the crown lengthening surgery, the control group patients wore DMG resin temporary crown material for gingival contouring, while the experimental group patients wore 3D printed resin temporary crowns for the same purpose. The patients were followed up in the outpatient clinic after wearing temporary crowns for 1 month, 3 months, and 6 months, respectively. The clinical results were evaluated in terms of marginal fit, red aesthetic index, and white aesthetic index.ResultsBased on the statistical analysis, the experimental group required significantly fewer follow-up visits and less time for guide design and fabrication compared to the control group. Additionally, the surgical time for the experimental group was significantly shorter than that of the control group. During the postoperative period between the 1st and 3rd month, the PES index scores for the marginal gingival level, proximal, and distal mesiodistal gingival papillae of the experimental group showed a trend of superiority over those of the control group. By the 6th month, the marginal gingival level exhibited a significant difference between the experimental and control groups. The experimental group demonstrated superior results to the control group in terms of shape, contour, and volume of the teeth, color, surface texture, and transparency of the restorations, and features during the 1st and 3rd postoperative months. In the 6th month, the comparative results indicated that the experimental group continued to exhibit superior outcomes to the control group in terms of the shape, color, surface texture, and transparency of the restorations, as well as the characteristics of the teeth. Additionally, the experimental group demonstrated significantly fewer gingival alterations than the control group at 1 month, 3 months, and 6 months post-procedure, with this difference being statistically significant. Furthermore, the combination of 3D printing technology and restorative techniques was utilized, resulting in consistent patient satisfaction.ConclusionDigitalisation plays an important role in anterior aesthetic restorations. The use of digital technology to manage the entire process of anterior cosmetic restorations can improve restorative results, reduce the number of follow-up appointments, shorten consultation time, and achieve better patient satisfaction.