Full Crown Restorations Research Articles

New intraoral digital impression with pneumatic gingival retraction used in the restoration of crown for posterior teeth: a case report

In fixed prosthodontics, clear exposure of the preparation margin is the prerequisite for obtaining accurate digital impressions and improving the marginal fit of restorations. To resolve the issues associated with the cord retraction technique, such as pain, acute injury, and prolonged procedural time, this study proposes a new technology for intraoral digital impression taking with pneumatic gingival retraction. The new scanning head blows a high-speed airflow that instantaneously separates the free gingiva, locally exposing the subgingival preparation margin. Combined with the farthest point preservation stitching algorithm based on the distance from the normal vector and high-speed laser scanning photography, it achieves global preparation edge data and gingival reconstruction, realizing painless, non-invasive, and efficient precise acquisition of the preparation margin. Using this new technique, a patient with a full porcelain crown restoration on a posterior tooth was treated. The digital impression revealed a clear margin of the preparation, and the crown made from this data has a good marginal fit.

Treatment decisions of patients with Class II Division 2 malocclusion and severe tooth wear: a systematic review

BackgroundThe treatment strategy for patients with severe tooth wear associated with Class II Division 2 malocclusion remains a major challenge for dental practitioners.ObjectivesTo systematically review and summarize the literature on treatment strategies, restoration procedures and clinical outcomes for Class II Division 2 malocclusion patients with severe tooth wear.MethodsA literature review was conducted using Pubmed, Embase, the Cochrane Library, and Web of Science to identify eligible articles. Publications until October 16th, 2023 were searched independently and cross-checked by two researchers.ResultsOf 1513 articles screened, 10 reports detailed treatment processes, including six males and four females aged 34–68 years old. Four articles recorded pre-treatment freeway space (FWS) values ranging from 5 to 9 mm. All ten cases had significant occlusal vertical dimension (OVD) loss and the increase in OVD after treatment ranged from 1 to 7 mm. Pre-prosthetic orthodontic treatment was performed in two cases, in one of which only the maxillary region was orthodontically treated. The most common restorations provided were full coverage restorations. In most cases, temporary restorations were applied before the permanent restorations for eight weeks to six months. Four different sequences of final restoration were proposed. Follow-up ranged from four months to six years and included seven patients, one of them showed symptoms of temporomandibular disorder (TMD).ConclusionsA multidisciplinary team (MDT) approach to treatment is recommended. Consideration of pre-prosthetic orthodontic treatment is essential. Commonly used cephalometric measurements for anterior teeth include the interincisal angle and collum angle. The increases in OVD ranging from 1 to 7 mm can be effectively accommodated. Temporary restorations are recommended to accommodate the OVD, and the transition periods of 8 weeks to 6 months help the patients adapted well. Four different sequences for final rehabilitation have demonstrated positive clinical outcomes. Full crown restorations have emerged as the preferred choice for the ultimate restoration of these patients.

Removal of fiber post under the guidance of digital guide plate and one-piece glass fiber posts-and-cores repair: a clinical report.

This study explores the potential application of computer aided design (CAD)/computer aided manufac-turing (CAM) for one-piece glass fiber posts and cores in restoring tooth defects post-removal of a broken fiber post using a digital guide plate. This paper reports a fractured left upper incisor fiber post removed using a customized needle and digital guide plate. Following root canal retreatment, CAD/CAM integrated fiber post-core and zirconia full crown restoration were completed. The occlusion testing was conducted using the T-Scan Ⅲ system. This study offers insights for managing secondary repair after fiber post fractures.

Evidence-based clinical management of localised tooth wear and a repeatedly dislodged posterior crown utilising the Dahl Concept.

This clinical case report demonstrates the use of the Dahl Concept in the management of the repeated dislodgement of a posterior full coverage crown associated with a reduced restorative space. The described technique harnesses the addition of resin composite and a temporarily cemented provisional full coverage crown to create sufficient restorative space for the cementation of a definitive posterior full coverage crown restoration at the six-month review.

FUNCTIONAL CROWN LENGTHENING AS A PRE-RESTORATIVE PROCEDURE IN THE AESTHETIC ZONE

Introduction: Crown lengthening is a surgical procedure to increase the height of the clinical crown for aesthetic and restorative purposes, or combination. The indications include treatment of subgingival caries and altered passive eruption. Functional crown lengthening for restorative purposes in the esthetic zone should consider the concept of biologic width and the ideal proportion of the dentogingival complex. Case: A 39-year-old male patient was referred from the Department of Conservative Dentistry, RSGM UGM Prof. Soedomo to expose the maxillary anterior teeth crowns for full crown and veneer restorations. Clinical examination showed 11, 12, and 12 post root canal treatment with 3-4 mm remaining crowns. Teeth 13, 21, 22, and 23 appear short, excessive gingival display of 3 mm, with a diagnosis of altered passive eruption type 1B. Treatment: Functional crown lengthening was performed by gingivectomy followed by flap elevation, ostectomy, and osteoplasty. A fenestration was found at the apical of 22 and treated with regenerative procedure. Full crowns and veneers insertion was done 3 months after surgery. Crown lengthening as a pre-restorative procedure is a multidisciplinary treatment that considers the need for restoration by re-establishing the biologic width, to prevent inflammation and bone loss. In addition, adequate post- surgical tissue healing time prior to restoration is necessary to avoid gingival margin rebound and to assure long-term success of the restoration. Conclusionn : Functional crown lengthening as a pre-restorative procedure in the esthetic zone can gives satisfactory and stable results, with careful examination and correct surgical procedure.

A data-driven approach for the partial reconstruction of individual human molar teeth using generative deep learning.

Due to the high prevalence of dental caries, fixed dental restorations are regularly required to restore compromised teeth or replace missing teeth while retaining function and aesthetic appearance. The fabrication of dental restorations, however, remains challenging due to the complexity of the human masticatory system as well as the unique morphology of each individual dentition. Adaptation and reworking are frequently required during the insertion of fixed dental prostheses (FDPs), which increase cost and treatment time. This article proposes a data-driven approach for the partial reconstruction of occlusal surfaces based on a data set that comprises 92 3D mesh files of full dental crown restorations. A Generative Adversarial Network (GAN) is considered for the given task in view of its ability to represent extensive data sets in an unsupervised manner with a wide variety of applications. Having demonstrated good capabilities in terms of image quality and training stability, StyleGAN-2 has been chosen as the main network for generating the occlusal surfaces. A 2D projection method is proposed in order to generate 2D representations of the provided 3D tooth data set for integration with the StyleGAN architecture. The reconstruction capabilities of the trained network are demonstrated by means of 4 common inlay types using a Bayesian Image Reconstruction method. This involves pre-processing the data in order to extract the necessary information of the tooth preparations required for the used method as well as the modification of the initial reconstruction loss. The reconstruction process yields satisfactory visual and quantitative results for all preparations with a root mean square error (RMSE) ranging from 0.02 mm to 0.18 mm. When compared against a clinical procedure for CAD inlay fabrication, the group of dentists preferred the GAN-based restorations for 3 of the total 4 inlay geometries. This article shows the effectiveness of the StyleGAN architecture with a downstream optimization process for the reconstruction of 4 different inlay geometries. The independence of the reconstruction process and the initial training of the GAN enables the application of the method for arbitrary inlay geometries without time-consuming retraining of the GAN.

Endodontic Microsurgery Outcomes over 10 Years and Associated Prognostic Factors: A Retrospective Cohort Study

IntroductionThis retrospective cohort study aimed to evaluate long-term healing outcomes (10–17.5 years) after contemporary endodontic microsurgery (EMS) and identify the associated prognostic factors. MethodsClinical and radiographic data of an EMS cohort (2006–2013) from the electronic database of the dental hospital were reviewed retrospectively by 2 independent examiners to determine their survival and healing outcomes, and potential prognostic factors were analyzed by Cox proportional hazards regression and logistic regression (α = 0.05). ResultsThrough strict inclusion and exclusion criteria and 721 EMS-treated teeth in the cohort, 309 (42.9%) were included (male = 35.0%; female = 65.0%; age = 45.83 ± 15.53 years) with a mean final follow-up of 152.26 ± 26.37 months (range, 120–211 months; median = 148 months). Clinical and radiographic assessments found an 80.5% 10-year survival rate with 63.4% of success. Collectively, tooth type, tooth mobility, preoperative lesion size, clinical crown-to-root ratio, and crown restorations at follow-up were significantly associated with long-term success and survival over 10 years. ConclusionsThe preoperative status and condition of the tooth including its alveolar bone support and adequate full-crown restorations may be relevant prognostic determinants of success and survival after EMS over time.

A Clinical Case of Feline Crown Restoration With Monolithic Zirconia

The most prevalent cause of tooth fractures in pets is trauma. Direct pulp exposure necessitates immediate extraction or root canal treatment. Monolithic zirconia are used as crown material in dentistry. It is reported a case of a 4-year-old female Ankara cat who had a monolithic zirconia crown restored following root canal therapy in the current study. An trauma to the cat's maxillary canine tooth resulted in a fracture that involved the pulp tissue. The tooth underwent root canal therapy and prepararation was done for fixed monolithic zirconia prosthetic full crown restoration. Maxillofacial and traumatic dentoalveolar injuries can decrease oral function, produce pain and inflammation, and negatively affect a cat's quality of life. Monolithic zirconia crowns are a new, significant restorative material that has been used rarely and little studied in veterinary dentistry despite having important material properties.

Effects of Polymeric Ceramic Inlay and Full Crown Restoration on Patients with Dental Defects

Effects of Polymeric Ceramic Inlay and Full Crown Restoration on Patients with Dental Defects

The effect of cement and impression methods on the marginal and internal adaptation of the current monolithic blocks - 3D scanning evaluation.

This research aimed to evaluate the marginal and internal gaps of crowns, which were produced using both digital and conventional impression techniques and cemented with various types of cement. For the full ceramic crown restoration, an anatomically prepared acrylic first molar phantom tooth (Frasaco GmbH, Germany) was scanned with Scanner S600 ARTI (Zirkonzahn). 160 PMMA analogues produced from the milling unit. Two impression methods were used: digital impressions by intraoral scanner (Aadva Intra Oral 3D Scanner, GC) and PVS impression. Cerasmart, Initial LRF Block, Zirconia Prettau and ICE Zircon monolithic blocks milled with M1 Milling Unit (Zirkonzahn). Restorations cemented with light-cured and dual-cured cements. (n = 10) Pre and post-cementation 3D images overlap was performed using Geomagic Control X (3D Systems, NC, USA). Data were analysed by using SPSS 25.0. p<0.05 difference was considered significant. Digital impressions were significantly higher than PVS impressions in all groups (p<0.05). A significant difference was found between the materials (p<0.05). Cerasmart showed a significantly more marginal gap than the other groups. Prettau and ICE Zircon crowns with the conventional impression group showed a significantly smaller marginal gap than the others. Monolithic crowns fabricated by CAD-CAM using the digital and conventional impression methods had clinically acceptable marginal and internal gaps. Crowns cemented with dual-cured cements showed significantly more marginal gap than light-cure groups. Key words:3D scanning, Marginal accuracy, Marginal fit, Monolithic crown.

Clinical management of vital and non-vital discolored tooth preparation stump shades: A clinical case series.

Traditional and modern-day laboratory techniques can be used to mask vital and non-vital discolored teeth. Two clinical case reports are presented showing different treatment approaches to differing clinical scenarios of partial coverage veneer and full coverage crown restorations, respectively. Feldspathic ceramics should be considered when customization of stump shade correction and equalization is required with minimum facial reduction with veneer restorations. Translucent zirconia (5 mol% Y2 O3 ) can be used to mask metal posts and core restorations on non-vital teeth using an opaquer material that is infused into the intaglio surface in the green state. Different clinical scenarios will present to the clinician in regard to discolored stump shades where understanding what laboratory material treatment options are available that will help guide definitive restoration types and ultimately tooth preparation design.

Retracted: Comparison of Short-Term Restorative Effects and Periodontal Health Status of Restorations Made of Different Materials in Full-Crown Restoration of Mandibular Premolar Tooth Defects.

[This retracts the article DOI: 10.1155/2022/3682741.].

A Retrospective Analysis of the Need for the Root Canal Therapy for the Full Crown Restorations: An Original Study.

There are numerous chances for pulpal irritation during the placement of a crown on a tooth. This study's goal was to find and examine the variables that influence the prevalence of routine root canal therapy after the teeth were restored with full coverage crowns. The hospital records were retrospectively evaluated from 2000 to 2010 for a decade. The demographics as well as the various variables that caused for the intervention with the root canal therapy for the teeth with the full crowns were evaluated. The values were compared for the significance. The total number of the teeth that were finalized in the study was 4308. Of the total teeth that were treated with full coverage crowns, 50% were metal ceramic, 42% were full ceramic, and 9% were full metal crowns. After 10 years, possibility that every tooth with a crown would survive was 91%. The most frequent adverse incident was the intervention with the RCT. Metal ceramic crowns had poor survival rates and needed the maximum intervention. Younger age-group had least survival rate than the older age-groups. Endodontic therapy is unlikely to be necessary after crown installation. As the patient's age declines and all-ceramic or PFM crowns are used, this risk rises.

Cox Regression Analysis of Prognostic Factors in Full Crown Restoration of Premolars with Cervical Defect

Objective: To study the prognostic factors in Full crown restoration of Premolars with cervical defect by analyzing long-term survival. Methods: A total of 432 Premolars with cervical defect, selected from 2012 Jan to 2014 Dec, were restored by Full crown. According to different repair methods, they were divided into resin repair group and post core repair group. The effect was analyzed by Cox regression analysis in 5-year follow-up. Results: Different repair methods (RR=0.567, 95% CI: 0.355~0.907), Teeth contact (RR=0.033, 95% CI: 0.016~0.840), Abutment teeth (RR=0.494, 95% CI: 0.308~0.793), Dentin shoulder collar (RR=11.465, 95% CI: 6.653~19.759), Defect size RR=0.386, 95% CI: 0.187~0.798) were the isolated factor influencing the prognosis. Further subgroup analysis shows that, the survival rate of the affected teeth as abutments restored with single crown fixed dentures is higher than that restored with fixed bridge dentures (χ²=4.141, P =0.0419). The survival rate of reinforced abutments restored with fiber posts is higher than that of reinforced abutments restored with metal posts (χ²=18.12, P =0.0001)。The C-index of the nomogram for prognosis was 0.838. Conclusion: In order to improve the long-term preservation rate, different restoration methods for Premolars with cervical defect should be selected according to different situations.

Rescanning of Digital Impressions’ Mesh Holes: In Vivo and In Vitro Accuracy Evaluation of Three Different Scanning Protocols

Several factors have been identified to have an influence over the accuracy of a digital impression: ambient lighting conditions, the presence of liquid on the intraoral structures, and the scanning patterns. The purpose of this study was to identify which protocol produced the most accurate digital impression regarding a one-preparation scenario in which data were acquired from a single uninterrupted scan, a rescanning of the area of interest in order to obtain more data, or the deletion of the area of interest followed by a rescan. An in vitro scenario using a typodont involving a single full-crown restoration was conceived alongside the selection of an in vivo case of a patient presenting an unrestored right mandibular first molar. The STL (standard tessellation language) reference models for each group were obtained using a high-resolution scanner (Freedom, HD; DOS). With the use of a Medit I700 (Medit, Seoul, South Korea) intraoral scanner, three different scanning protocols were conducted on the typodont and on the clinical case. The measured data (IOS scans) were sorted and further analyzed with the help of Geomagic Control X (Version:16.0.2.16496, 3D Systems, Wilsonville, OR, USA). The Kolmogorov–Smirnov test for normality was conducted on the whole set of data. The nonparametric data set underwent Kruskal–Wallis test analysis while the parametric data set underwent a one-way ANOVA test (the level of significance was set to α = 0.05). For the in vitro case, the “SINGLESCAN” group displayed the best trueness; the “DELETE&amp;RESCAN” group displayed the best precision. Regarding the in vivo case, the “SINGLESCAN” group also displayed the best trueness; the “RESCAN” group displayed the best precision. Statistical differences were found in the trueness and precision of the IOS scans captured with the three different scanning protocols, but the differences were so small that they could be considered clinically negligible.

Retracted: Effect of Root Canal Therapy Combined with Full Crown Restoration on the Level of Inflammatory Factors and Chewing Function in Patients with Cracked Teeth and Chronic Pulpitis.

[This retracts the article DOI: 10.1155/2021/3299349.].

Bite force evaluation at maximal intercuspal position: An in vivo comparative study between stainless steel and zirconia crowns on primary molar teeth.

The objective of this study was to clinically evaluate and compare the mean bite force changes at maximum intercuspal position, along with parental satisfaction following full crown restoration using stainless steel crown/zirconia crown on primary molar teeth using digital occlusal analysis system T-Scan III (Tekscan Corp, Boston, Mass., USA). Thirty-six primary molars of children aged 6-9 years with pulpal involvement were selected for the study. The selected teeth were allocated to either of the two groups using simple random sampling technique: Group A = stainless steel crowned teeth and Group B = zirconia crowned teeth. The mean bite force was recorded before the placement of the crown, after the placement of the crown, and after 1 month-follow-up. The inter-group and intra-group comparison was done among the groups. After the placement of the crown, parents were asked to fill out a questionnaire for assessing parental satisfaction. A significant result in the bite force on crowned tooth, vertical dimension was seen from baseline to 1-month follow-up between the SSC and zirconia groups. In the zirconia crown group, the mean bite force was more compared to the stainless steel crown group. Parents' satisfaction was higher with zirconia crown in terms of color and esthetics. SSC is more acceptable than zirconia crown since occlusal re-equilibration was attained better in SSC as compared to zirconia crown.

Effect of margin design changes on stress distribution in zirconia-based full-crown restorations: A three-dimensional finite element analysis

Aim: The aim of this study was to evaluate the effect of margin design changes on the stress distribution in zirconia-based full-crown restorations using three-dimensional finite element analysis. Methodology: For use in the design of full-crown restorations, tooth number 16 was prepared in chamfer step type on a maxillary tooth jaw model (AG-3: Tipodont, Frasaco, Germany). The prepared tooth was scanned using a desktop scanner, and a three-dimensional finite element analysis model was obtained. Zirconia frameworks are divided into three groups according to the margin design: uniform thickness hood type (Model A), ¾ partial crown form (Model B), and a lingual-band type (Model C). The crown form was completed using feldspathic porcelain as the superstructure material. To determine the stress distribution of the margin design on the restoration, the maximum principal stress (MPa) values under a 600 N vertical load were investigated. Results: The maximum stress on the zirconia framework was observed in Model A (82.90 MPa), and the maximum stress on the tooth was observed in Model B (49.34 MPa). The maximum stress on the feldspathic porcelain was highest in Model A (21.860 MPa), and the minimum stress on the tooth occurred in Model B (13.33 MPa). In the zirconia framework, the lowest stress was 11.54 MPa (Model B). Conclusion: The framework design was shown to affect the force generated on the restoration and transmitted to the tooth. The results of the present study will help dentists determine the ideal infrastructure design for zirconia-based restorations. Lingual band designs were found to be successful. How to cite this article: Güntekin N, Mohammadi R, Tunçdemir AR. Effect of margin design changes on stress distribution in zirconia-based full-crown restorations: A three-dimensional finite element analysis. Int Dent Res 2022;12(Suppl.1):10-5. https://doi.org/10.5577/intdentres.439 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Evaluation of the marginal adaptation and gingival status of full-crown restorations using an intraoral camera

ObjectiveThe purpose of this study was to compare the usefulness of intraoral photographs, acquired with a household intraoral camera operating in conventional, calibrated, and polarized modes, with clinical examinations for assessing the marginal adaptation and gingival status of full-crown restorations.MethodsClinical examinations were performed by a prosthodontist who classified the marginal adaptation of full-crown restorations according to FDI World Dental Federation criteria, and a periodontal expert who classified gingival status according to the Modified Gingival Index (MGI). The margins and gingival status of the conventional, calibration, and polarization groups of full-crown restorations were independently assessed by three evaluators who obtained photographs using an intraoral camera. Cases where at least two of three assessors were in agreement were analyzed using Cohen’s kappa coefficient and the chi-square test, and the sensitivity and specificity were calculated.ResultsThe conventional, calibration, and polarization groups differed significantly in marginal and gingival status of full-crown restorations. In the calibration group, there was good agreement between the camera-based and oral clinical examinations in terms of the gingival status of full-crown restorations (kappa = 0.945), with 100% sensitivity and 91.67% specificity; this was also the case in the polarization group with respect to the margins of full-crown restorations (kappa = 0.917, sensitivity = 97.22%, specificity = 94.44%).ConclusionsAn intraoral camera with black and white calibrated images is useful to assess the gingival status of full-crown restorations. Polarization mode can be used to assess the marginal adaptation of full-crown restorations. The camera is a feasible and valid diagnostic aid.

Finite element analysis and biomimetic optimal design of full-crown restoration

Objective: To improve the mechanical properties of full-crown restorations and illuminate the optimal elastic modulus distribution through bionic optimization design and finite element analysis (FEA). Methods: Seven 3D models of mandibular first premolars with different full-crown restorations were constructed: (A) zirconia monolithic crown, (B) lithium disilicate monolithic crown, (C) zirconia bilayer crown, (D) lithium disilicate bilayer crown, (E) 8-layer crown referred to the elastic modulus distribution of human enamel, (F) and (G) were 8-layer crowns with elastic modulus distribution calculated by a genetic algorithm (GA) to minimize the tensile stresses in the crown and the shear stresses at the cementing line, respectively. Results in the crowns and cementing lines were obtained with maximum principal stress after applying a static load of 600 N. Results: The principal tensile stresses in the full-crown restorations were mainly concentrated in the cervical margins and the crown-cementing interface. Among them, G exhibited a peak tensile stress of 25.79 MPa, which decreased to 17.72 MPa in E and 16.25 MPa in F; The principal shear stresses in cementing lines were concentrated along the margins and low on the axial wall. The peak shear stress of the cementing line of E and F was 11.81 MPa and 11.79 MPa, respectively. While G was found to has the lowest peak shear stress of 6.14 MPa. Conclusion: The elastic modulus distribution optimized by GA to reduce the peak shear stress of the cementing line can better improve the mechanical properties of the full-crown restoration.