Provisional Crown Research Articles

Surface roughness and surface hardness changes in composite resin provisional crown before and after brushing with whitening toothpaste

Objective: To determine the surface roughness and surface hardness difference in composite resin provisional crown before and after brushing with whitening toothpaste.
 Material and Methods: This was a pre- and post-test group design experimental study. In this study, the sample was a composite resin provisional crown based on bis-acryl. The number of samples in this study was 32 samples, 16 for the surface roughness test and the other 16 for the surface hardness test. Each sample was brushed using a V8-Brushing Machine Modified, then tested for surface roughness and hardness using a Profilometer and Vickers Hardness Tester.
 Results: The paired T test was used to analyze the results statistically. There was a significant difference between the groups before and after brushing with whitening toothpaste. (p<0.05).
 Conclusion: After simulated brushing with whitening toothpaste, there was a change in the the provisional crown material surface roughness and hardness value.

Influence of aging process and restoration thickness on the fracture resistance of provisional crowns: A comparative study

BackgroundThe advancement of digital dentistry enhanced the fabrication of indirect provisional restorations utilizing durable materials, yet the performance of provisional crowns fabricated with various techniques, and different thickness remains unknown. Thus, this in-vitro study aimed to evaluate the influence of restoration thickness and aging on the fracture behavior of provisional crowns fabricated using different techniques. MethodsA dentiform maxillary first molar was prepared using a highly filled epoxy resin material to construct identical die replicas. Four groups of provisional crowns were fabricated: Group 1 was milled at 1.5 mm occlusal thickness; Group 2 was milled at 0.9 mm thickness; Group 3 was 3D-printed at 1.5 mm occlusal thickness; and Group 4 was 3D-printed at 0.9 mm occlusal thickness. Eight crowns from each group were subjected to a thermocycling process for 5000 cycles between baths held at 5 °C and 55 °C with a dwell time of 30 s and transfer time of 5 s. All crowns (aged and non-aged (control)) were loaded for fracturing using a universal testing machine at a 0.5 mm/min crosshead speed. Data were analyzed using a two-way analysis of variance and multiple comparisons at (α = 0.05). ResultsThe maximum mean force load was found in the non-aged milled group (M1.5) at 1706.36 ± 124.07 N; the minimum mean force load was recorded for the aged 3D-printed group (3D0.9) at 552.49 ± 173.46 N. A significant difference was observed before and after thermocycling (p < 0.01). ConclusionComputer-aided design and manufacture of milled provisional crowns is superior to 3D-printed crowns for fracture resistance.

Comparative Microscopic and Radiographic Evaluation of Proximal Marginal Integrity of CAD/CAM PMMA Crown and CAD/CAM Zirconia Monolithic Crown- An In-vitro Study

ABSTRACTS&#x0D; Aim: to evaluate and compare proximal marginal integrity radiographically and microscopically of CAD/CAM PMMA crown and CAD/CAM monolithic zirconia crown.&#x0D; Materials and methods: Fifteen maxillary or mandibular molar teeth with standardized anatomic preparation for provisional crown and monolithic zirconia crown were scanned with a 3-dimensional laboratory scanner. CAD/CAM crowns were designed 3-dimensionally using exocad software and then milled from presintered blocks in a milling machine. The proximal marginal integrity of CAD/CAM PMMA and monolithic zirconia crown were evaluated radiographically and microscopically. For radiographic evaluation, radiopaque dye is used to measured proximal marginal discrepancies on six reference points on PMMA crown. A digital microscope was used to measure the marginal discrepancies on six reference points on PMMA and zirconia crown. Photographs of the proximal marginal areas were captured at six reference lines at standardized orientation and placement of the samples. In all photographs margin was traced with the help of HiViewSetup software. The mean marginal discrepancies for each group were analysed using chi-square test and man whitney U test.&#x0D; Results: the test result shows there were no significant differences in radiographic and microscopic evaluation of CAD/CAM PMMA crown and CAD/CAM monolithic zirconia crown.&#x0D; Conclusion:&#x0D; It is found that radiographically, PMMA crown had greater marginal discrepancy as compared to the Zirconia crown. Microscopically, PMMA crown and the CAD/CAM monolithic zirconia crown had almost similar marginal discrepancy (statistically non- significant).

Gingival Contour in BOPT: A Review of Provisional Crown Guidance

Gingival Contour in BOPT: A Review of Provisional Crown Guidance

Marginal and Internal Gaps, Surface Roughness and Fracture Resistance of Provisional Crowns Fabricated With 3D Printing and Milling Systems.

To compare the marginal and internal gap, surface roughness, fracture resistance and mode of failure of provisional crowns fabricated with 3D printing and CAD/CAM manufacturing techniques. A maxillary first premolar was prepared for an all-ceramic crown and reproduced in cobalt-chromium metal dies (n=30) following CAD/CAM technology. The die was digitally scanned and exocad software was used to design the missing crown, which was manufactured using a CAM milling machine and two types of 3D printing machines (SLA and DLP) to produce 10 provisional crowns per group. The crowns were cemented to their respective dies and stored in water (24 hours; 37°C) followed by 600 thermal cycles (5°C/55°C) and 100,000 mechanical cycles (at 50N). Marginal and internal gap measurements were carried out using a 3D superimposition technique. Surface roughness (Ra) was determined using a profilometer at 0.5 mm/second cross-head speed. The crowns were loaded to fracture at 0.5 mm/minute cross-head speed. Fracture forces and mode of failure were recorded, and data were analyzed using one-way analysis of variance (ANOVA) and multiple comparisons post hoc tests (p<0.05). The SLA group exhibited higher marginal and internal gaps than both the CAD/CAM and DLP groups (p<0.05). The DLP group showed higher surface roughness than the CAD/CAM and SLA groups (p<0.01). The CAD/CAM and SLA groups showed higher resistance to fracture than the DLP (p<0.05) group. Mode of failure I: Minimal crown fracture or crack, was predominate among DLP and SLA crowns (60%), while the Mode II: Less than half of the crown lost, was predominant among CAD/CAM crowns (60%). Crowns manufactured following CAD/CAM technique have better marginal and internal fit, surface roughness than SLA and DLP crowns. The CAD/CAM and SLA crowns showed higher resistance to fracture than the DLP crowns.

Clinical and Radiographical Evaluation of Immediate Loading of Narrow Diameter Dental Implants.

The present study aimed to evaluate the peri-implant tissue response and marginal bone levels of immediately loaded narrow diameter dental implants. In this study, 10 patients with single maxillary anterior edentulous space were included. Implants were placed and immediate provisional crown was given without any centric or eccentric contacts. After three months, a definitive restoration was placed. All the clinical and radiographical parameters were evaluated.

The Use of a Soft Tissue Substitute at Immediate Postextractive Implants to Reduce Tissue Shrinkage: One-Year Results from a Randomized Controlled Trial.

The aim of this randomized controlled trial (RCT) was to evaluate whether placement of a soft tissue graft substitute (STGS) could decrease peri-implant tissue shrinkage at immediate postextractive implants. Twenty patients with one missing tooth between two adjacent healthy teeth in esthetic areas and at least 4 mm of bone apical to the tooth apex were randomly allocated (after tooth extraction) to receive (n = 10; test group) or not receive (n = 10; control group) a subepithelial buccal STGS. Implants were inserted with a torque of at least 30 Ncm, and sites were grafted with a cancellous particulate allograft. All patients were restored with nonoccluding immediate provisional screw-retained crowns, replaced after 6 months by definitive metal-ceramic crowns. One year after loading, no dropouts, crown or implant failure, or complications occurred. No statistically significant difference or trends in volume shrinkage, esthetics, peri-implant marginal bone loss, and keratinized mucosa heights between the two groups were observed. Acknowledging that the sample size was small, no clinical benefit could be observed for the use of a STGS in immediate postextractive implants.

Thermal Changes of One-Piece Versus Two-Piece Implants During Setting of an Autopolymerized Acrylic Resin.

Purpose: To evaluate differences in the temperature rise at the cervical area of one-piece vs two-piece implants during the setting of relined provisional crowns. Materials and Methods: A K-type thermocouple was fixed to the coronal thread of 15 one-piece implants and 15 two-piece implants that were mounted on a plexiglass apparatus. Baseline temperature (Bl Temp) was recorded before starting the curing process. The maximum temperature (Max Temp) reached during the process in both implant groups was also recorded. Total heat flux (THF) was calculated as well as the thermal amplitude (Temp-Amp) at the implant surface. Finally, the differences between the implant types were compared using unpaired t test. Results: The increase in temperature from baseline was statistically significantly greater in the one-piece implants than in the two-piece implants (P < .01). Similarly, the THF and Temp-Amp were significantly greater in the one-piece implants compared to two-piece implants (P < .01). Conclusions: The polymerization of PMMA-based resin temporary crowns produces a significant temperature rise in both one-piece and two-piece implants. It is advisable to use two-piece implants to restore immediately loaded implants to reduce the risk to implant surroundings that may occur due to the temperature rise at the implant neck.

Esthetic outcomes of immediate implants placement following immediate restoration: Controlled clinical trial

The aim of this controlled clinical trial was to evaluate the variation in the thickness of the buccal bone plate and the position of the gingival margin in single implants installed in extraction socket and in healed ridges, both with immediate loading in aesthetic region. Materials and Methods: individuals in group 1 (n=7) were treated with minimally invasive tooth extraction, cone morse implant (Neodent®), xenogene bone “gap” filling (Bio Oss®) and cementation of provisional crown. Individuals in group 2 (n=3), in edentulous unitary ridges, received a cone morse implant (Neodent®) and provisional crown cementation. The coronal (C), mid (M) and apical (A) points of the buccal bone plate (BBP) were measured by means of computed tomography and, with the aid of a probing guide, the measurements of the position of the gingival margin (PGM) were performed at the mesial (M), vestibular (V) and distal (D) points, both analyzes were assessed in the preoperative (T0), immediate postoperative (T1) and six months postoperatively (T2). Results: in the analysis of buccal bone plate (BBP), no statistical differences were observed in the interaction of period and group factors, the same happened when comparing only the different periods. Group 1, when compared to group 2 in T1, presented higher averages in the buccal bone plate (p &lt;0.05), and this statistical difference was significant. In the PGM analysis, there was no significant statistical difference between the groups and periods interaction, the same could be observed when comparing the groups with each other (p&gt; 0.05). A statistical difference between time T0 and T2 was observed, with time T2 having a mean of the measurements greater than the time T0 in both groups. Conclusions: the treatment conferred in group 1 was shown to be a reliable option, with results of vestibular bone thickness and gingival level stable in the observed periods, when compared with group 2 treatment. With similar results between groups, the advantages of immediate implant as reduction of postoperative morbidity, reduction of medication use and maintenance of the perimplant framework become attractive for indication of the technique tested

Comparison of the marginal and internal fit of PMMA interim crowns printed with different layer thicknesses in 3D-printing technique.

The aim of this in vitro study was to compare the effect of printing layer thickness on the marginal and internal fit of interim crowns. A maxillary first molar model was prepared for ceramic restoration. Thirty-six crowns were printed with three different layer thicknesses using a digital light processing-based three-dimensional printer (25, 50, and 100 µm [LT 25, LT 50, and LT 100]). The marginal and internal gaps of the crowns were measured with replica technique. An analysis of variance was conducted to determine if there were significant differences between the groups (ɑ = .05). The marginal gap of LT 100 group was significantly higher than that LT 25 (p = .002) and LT 50 groups (p ≤ .001). The LT 25 group has significantly larger axial gaps than LT 50 group (p = .013); however, there were no statistically significant differences between other groups. The LT 50 group showed the smallest axio-occlusal gap. The mean occlusal gap differed significantly by printing layer thickness (p ≤ .001), with the largest gap occurring for LT 100. Provisional crowns printed with 50 µm layer thickness provided the best marginal and internal fit. It is recommended that provisional crowns be printed with a 50 µm layer thickness to ensure optimal marginal and internal fit.

Can patients detect peri‑implant mucosal inflammation? Results from a multicentre randomized trial

PurposeThe objective of this study was to compare patient-reported outcomes (PROs) of peri‑implant soft tissue inflammation and aesthetics around single-tooth implants in the anterior maxillary region with three different implant-abutment interface designs. MethodsParticipants were randomized to one of three different types of implant-abutment interface designs [Conical (CI), flat-to-flat (FI), and Platform Switched (PS)]. Implants and provisional crowns with prefabricated titanium abutments were placed 5 months following extraction and/or ridge augmentation. Permanent ceramic crowns with zirconia abutments were placed after 12 weeks. To assess PROs, appearance and inflammation questionnaires were completed from provisional crown placement to the 3-year follow-up. ResultsTooth appearance at the 3-year follow-up revealed a difference amongst CI, FI and PS implants (p=0.049; Kruskal-Wallis test). PS was rated better than FI (p=0.047) at 1 year for appearance of soft-tissue and satisfaction with colour. There were no differences for self-consciousness, smile and pain/discomfort while eating/hard food items. ConclusionsAlthough participants tended to rate the health of mucosa around PS implants as slighty better than the other two implant systems, the differences were minimal and inconsistent. Thus, patient satisfaction in terms self-perceived gingival health and esthetics was high for all 3 systems tested, suggesting that patients are unable to detect mucosal inflammation. Clinical SignificancePatients find it difficult to perceive mucosal inflammation; hence, it is recommended that patients attend implant follow-up visits, even if they do not perceive inflammation. The study suggests that there is a relationship between the PROs and the clinical outcomes of tested implants.

Mechanical Properties of Three-Dimensional Printed Provisional Resin Materials for Crown and Fixed Dental Prosthesis: A Systematic Review.

The emergence of digital dentistry has led to the introduction of various three-dimensional (3D) printing materials in the market, specifically for provisional fixed restoration. This study aimed to undertake a systematic review of the published literature on the Mechanical Properties of 3D- Printed Provisional Resin Materials for crown and fixed dental prosthesis (FDP). The electronic database on PubMed/Medline was searched for relevant studies. The search retrieved articles that were published from January 2011 to March 2023. The established focus question was: "Do provisional 3D-printed materials have better mechanical properties than conventional or milled provisional materials?". The systematically extracted data included the researcher's name(s), publication year, evaluation method, number of samples, types of materials, and study outcome. A total of 19 studies were included in this systematic review. These studies examined different aspects of the mechanical properties of 3D-printed provisional materials. Flexural Strength and Microhardness were the frequently used mechanical testing. Furthermore, 3D-printed provisional restorations showed higher hardness, smoother surfaces, less wear volume loss, and higher wear resistance compared to either milled or conventional, or both. 3D-printed provisional resin materials appear to be a promising option for fabricating provisional crowns and FDPs.

Hard and soft tissue healing around teeth prepared with the biologically oriented preparation technique and restored with provisional crowns: An in vivo experimental investigation.

To evaluate the hard and soft tissues healing around teeth prepared with the biologically oriented preparation technique (BOPT) versus the chamfer technique versus non-prepared teeth. Thirty-two teeth in eight beagle dogs were randomly prepared with the BOPT (test = 16) or chamfer (control = 16) techniques and covered with polymethylmethacrylate crowns as provisional restorations. Sixteen negative controls (non-prepared teeth) were also used for comparison. Histological description and histomorphometrical measurements of the periodontal tissues were collected at 4 and 12 weeks in 7 out of 8 dogs, including the soft tissue height and thickness, and the horizontal and vertical bone dimensions. When compared with negative controls, test and control preparation techniques exhibited a more apical location of the free gingival margin with respect to the cement-enamel junction (∆ = 1.1 mm for both groups at 4 weeks (p < .05), 0.99 mm for the test group (p = .043) and 0.20 mm for control group (p = 1.000) at 12 weeks). There were no significant differences between test and control groups with respect to vertical and horizontal histometric measurements. The BOPT and chamfer tooth preparation protocols induced similar qualitative and quantitative changes in the healing of the supra-crestal soft tissue complex, when compared with non-prepared teeth. Despite the limited amount of power, it appeared that differences between the tested preparation techniques were not statistically significant.

Cytotoxicity of dental self-curing resin for a temporary crown: an in vitro study.

Residual monomer tests using high-performance liquid chromatography and cytotoxicity tests were performed to analyze the effect on the oral mucosa of a self-curing resin for provisional crown production. A cytotoxicity test was performed to confirm whether leaked residual monomers directly affected oral mucosal cells. The cytotoxicity of the liquid and solid resin polymers was measured using a water-soluble tetrazolium (WST) test and microplate reader. In the WST assay using a microplate reader, 73.4% of the cells survived at a concentration of 0.2% liquid resin polymer. The cytotoxicity of the liquid resin polymer was low at ≤0.2%. For the solid resins, when 100% of the eluate was used from each specimen, the average cell viability was 91.3% for the solid resin polymer and 100% for the hand-mixed self-curing resin, which is higher than the cell viability standard of 70%. The cytotoxicity of the solid resin polymer was low. Because the polymerization process of the self-curing resin may have harmful effects on the oral mucosa during the second and third stages, the solid resin should be manufactured indirectly using a dental model.

Performance of indirect technique in peri‐implant soft tissue contour duplication in the anterior maxilla: A clinical pilot study

To evaluate the performance of the indirect technique in peri-implant soft tissue contour duplication after the delivery procedure in the anterior maxilla. Patients with single implant-supported fixed restorations in the anterior maxilla were recruited. For the impression procedure, an intraoral scan was acquired by both the direct and the indirect techniques. For the delivery procedure, implants were randomly allocated into one of the two groups according to the approaches of digital impression preceding definite crown fabrication (A-direct technique; B-indirect technique) and were scanned again after the definite crown delivery. The stereolithography files were superimposed to analyze changes in peri-implant soft tissue contour after the delivery procedure. The main outcomes were dimensional deviations of peri-implant mucosa, and the secondary outcome was differences in the pink esthetic score (PES). A total of 20 implants that underwent the complete workflow were included. After the delivery procedure, significant deviations in palatal tissue thickness between the provisional and definite crowns were observed in Group A but these were absent in Group B. Additionally, deviations in labial thickness (0.27 ± 0.12 mm vs. 0.08 ± 0.09 mm) and palatal thickness (0.17 ± 0.15 mm vs. 0.03 ± 0.08 mm), and labial volume of soft tissue (1.87 ± 0.94 mm3 vs. 0.75 ± 0.74 mm3 ) in Group A were significantly higher than those in Group B. No significant differences in PES were found. The indirect technique of scanning the provisional crown can more accurately duplicate the peri-implant soft tissue contour than the direct technique, resulting in a smaller deviation of the soft tissue in the delivery procedure.

ASSESSMENT OF ORTHOPEDIC TREATMENT LATE RESULTS OF PATIENTS WITH FIXED PARTIAL DENTURES DUE TO THE FUNCTIONAL STATE OF ABUTMENT TEETH

The scientific work highlights the results of an index assessment of the periodontal condition of patients abutment teeth with dentition defects which were replaced with metal-ceramic fixed partial dentures due to partial teeth loss. Since during the preparation of abutment teeth there is sometimes a need for endodontic treatment of them due to medical indications, we investigated the state of the periodontium before, during and after treatment and compared index indicators of pulpless teeth with teeth in which the vascular-nerve bundle was preserved. It was established that the periodontium of the vital tooth recovers and functions much better in comparison with the surrounding dental tissues of a nonvital tooth. Where there are inflammatory changes, which are objectively caused by pronounced swelling and bleeding of the gingival papilla. It is caused due to rubber dam pressure, which in turn is confirmed by reliable data of index indicators determined in various the terms of the treatment.&#x0D; After conducting a detailed examination of patients with vital abutment teeth with defects in the hard tissues of the teeth, we found that in the age group of 30-39 years, the most common defect in the hard tissues of the teeth was caries damage, which was observed in 8 patients (72.7%), damage due to injuries was found in 2 patients (18.2%), enamel hypoplasia was found in 2 patients (18.2%).&#x0D; Treatment of partial adentia involves the preparation of abutment teeth followed by the manufacture of fixed bridge prostheses. However, the vitality of the abutment tooth should be taken into account and the reserve forces of the periodontium should be taken into account in order to prevent functional overload. It is also necessary to monitor the hygienic condition of the oral cavity during the treatment and at various times after its completion.&#x0D; The peculiarity of the proposed method of preparation of vital upper and lower abutment teeth consists in the creation of a champfer on the vestibular surface with the transition to an imitation of a champfer on the oral surface, under constant control of the thickness of the peripulpal dentin using a dentometer with the use of full water cooling and subsequent fixation of provisional crowns. The use of a complex of diagnostic techniques for full control of the effectiveness of treatment during and after prosthetics at different times is substantiated and proposed.&#x0D; The gnathodynamometric study was carried out using an advanced device, the VIZIR E1000 gnathodynamometer: the plates placed between the opposing teeth were bitten, as a result of which the load was digitized using a flexible connection through an analog-digital converter and displayed on the display of a computer program, displayed graphically in newtons (N), the time of the masticatory load was also recorded in seconds.&#x0D; Using data from clinical indices, it was determined that the preservation of vital teeth is a reliable criterion of the effectiveness of the use of partial fixed prostheses than the use of pulpless teeth. The absence of periapical trauma in vital teeth, which occurs in pulpless teeth due to extirpation of the neurovascular bundle, is demonstrated by the Russel index, and other indices also demonstrate mucosal irritation caused by the use of rubber dams due to the need for quality endodontic treatment.

Effect of three-dimensional target and reference data alignment method in an open digital dental communication application on the external surface trueness of CAD-CAM provisional crowns

Effect of three-dimensional target and reference data alignment method in an open digital dental communication application on the external surface trueness of CAD-CAM provisional crowns

Accuracy of Dental Models Fabricated Using Recycled Poly-Lactic Acid.

Based on the hypothesis that the fabrication of dental models using fused deposition modeling and poly-lactic acid (PLA), followed by recycling and reusing, would reduce industrial waste, we aimed to compare the accuracies of virgin and recycled PLA models. The PLA models were recycled using a crusher and a filament-manufacturing machine. Virgin PLA was labeled R, and the first, second, and third recycles were labeled R1, R2, and R3, respectively. To determine the accuracies of the virgin and reused PLA models, identical provisional crowns were fitted, and marginal fits were obtained using micro-computed tomography. A marginal fit of 120 µm was deemed acceptable based on previous literature. The mesial, distal, buccal, and palatal centers were set at M, D, B, and P, respectively. The mean value of each measurement point was considered as the result. When comparing the accuracies of R and R1, R2, and R3, significant differences were noted between R and R3 at B, R and R2, R3 at P, and R and R3 at D (p < 0.05). No significant difference was observed at M. This study demonstrates that PLA can be recycled only once owing to accuracy limitations.

Validation of the Implant Stability Test for Implant Provisional Crowns: An In Vitro Study

Implant treatment has evolved and is now performed using various techniques. However, the osseointegration duration required for poor primary stability or immediate loading is unclear and depends largely on the surgeon’s experience. We sought to verify whether implant stability can be quantified after immediate loading, using AnyCheck®. Six implants were placed in simulated bone blocks classified by bone quality as D1–D4 and further divided into healing abutment and provisional crown groups. The implant stability test (IST) values of both groups were measured using AnyCheck®. All bone qualities from D1 to D4 differed significantly between the provisional crown and healing abutment groups (p &lt; 0.001). In both groups, the IST values were the highest for D1 bone and lowest for D4 bone. There were significant differences in bone quality between the provisional crown and healing abutment groups. The correlations between the groups differed based on bone quality. However, the IST values of both groups differed by a minimum of 4 and maximum of 7. These results suggest that AnyCheck® is useful for quantifying the implant stability after immediate loading. Using an index to quantify the implant and bone stability for immediate loading may shorten treatment duration and increase success rates.

Vertical tooth preparation technique in aesthetic zone: Report of two patients

Abutments can be prepared in fixed dental prosthesis using horizontal and vertical preparation techniques. In vertical preparation abutments are prepared without a finish line by introducing a diamond rotary instrument into the sulcus to eliminate the cementoenamel junction and creating a new prosthetic cementoenamel junction. Vertical preparation technique in fixed dental prosthesis allows us to retrieve biologically compromised situations. With vertical preparations and over contoured provisional crowns, one can control zenith positions and thicken gingival biotypes. This in time gives us long lasting, stable tissue aesthetics around definitive restorations. This article describes 2 patients whose dental abutments were prepared using vertical preparation technique and 12 months follow up for restoration of teeth in aesthetic zone. Vertical preparation technique provides feather edge preparation and with interaction between preparation, restoration and gingiva aid in gingival thickening and adaptation to new prosthetic cementoenamel junction (CEJ) achieving soft tissue stability over long term.