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The Journal of Clinical Pediatric... May 2024The purpose of this study was to quantitatively evaluate adhesive remnants on the enamel surface following bracket debonding using a freezing element. Thirty-six sound...
The purpose of this study was to quantitatively evaluate adhesive remnants on the enamel surface following bracket debonding using a freezing element. Thirty-six sound premolars were used in this study. In each case, a bracket was bonded onto each tooth with conventional light-cured composite resin and de-bonded after one week. Freezing of the underlying composite through the bracket was performed immediately before debonding with a portable cryosurgical system (-55 °C). Specimens were divided into three groups according to the duration of freezing: a control group without freezing was used as a reference and two interventional groups with different durations of freezing (15 or 40 s). Brackets were removed by using debonding pliers to squeeze the wings of the bracket in an occluso-gingival manner. Adhesive remnants on the tooth were then quantitatively evaluated by stereo-microscopy. Pearson's Chi-squared test was used to investigate the relationship between the proportion of remaining resin and the group of teeth. In the control group, 100% of the composite remained on the enamel surface of all specimens. Significantly less adhesive remnants were found in the intervention groups ( = 0.001 for the 15 s group and = 0.043 for the 40 s group). There was no significant difference between the two interventions ( = 0.165) in terms of the proportion of remaining adhesive remnants. Freezing of the bracket and the underlying adhesive resin prior to bracket debonding may favorably alter the behavioral pattern of composite fracture, thus reducing the extent of adhesive remnants on the enamel. Increasing the freezing time from 15 to 40 s did not exert significant effects on adhesive remnants following debonding. Further research now needs to investigate the effect of freezing on the mechanical properties of the adhesive remnants and its effect on pulp vitality over both short- and long-terms.
Topics: Humans; Dental Debonding; Freezing; Orthodontic Brackets; Composite Resins; Dental Enamel; In Vitro Techniques; Resin Cements; Dental Cements; Bicuspid; Materials Testing
PubMed: 38755979
DOI: 10.22514/jocpd.2024.056 -
Clinical Oral Investigations May 2024This study aimed to evaluate the fracture strength of teeth restored using fiber-reinforced direct restorative materials after endodontic treatment with a conservative...
Effect of fiber-reinforced direct restorative materials on the fracture resistance of endodontically treated mandibular molars restored with a conservative endodontic cavity design.
OBJECTIVE
This study aimed to evaluate the fracture strength of teeth restored using fiber-reinforced direct restorative materials after endodontic treatment with a conservative mesio-occlusal access cavity design.
MATERIALS AND METHODS
A total of 100 extracted intact mandibular first molars were selected and distributed into a positive control group where teeth left intact and the following four test groups comprised of teeth with conservative mesio-occlusal access cavities that had undergone root canal treatment (n = 20/group): access cavity without restoration (negative control), bulk-fill resin composite with horizontal glass fiber post reinforcement, fiber-reinforced composite with bulk-fill resin and bulk-fill resin composite. Following thermocycling (10,000 cycles), fracture resistance was measured using a universal testing machine. Statistical analyses (one-way analysis of variance and the Tamhane test) were performed, and statistical significance was set at p < 0.05.
RESULTS
Groups with minimally invasive access cavities had lower fracture strength than intact teeth, regardless of the restoration material (p < 0.05). Fiber-reinforced composite groups demonstrated higher fracture strength than bulk-fill resin composite alone (p < 0.05). Fracture types varied among groups, with restorable fractures predominant in the fiber-reinforced composite groups.
CONCLUSION
This study suggests that using fiber-reinforced composite materials, especially in combination with bulk-fill resin composites, can effectively enhance the fracture strength of endodontically treated teeth with conservative access cavities. However, using only bulk-fill resin composite is not recommended based on the fracture strength results.
CLINICAL SIGNIFICANCE
When teeth that undergo endodontic treatment are restored using a conservative access cavity design and fiber-reinforced composite materials, especially in combination with bulk-fill resin composites, the fracture strength of the teeth can be effectively increased.
Topics: Composite Resins; Humans; Molar; Tooth, Nonvital; Dental Stress Analysis; Tooth Fractures; Dental Restoration, Permanent; In Vitro Techniques; Mandible; Materials Testing; Glass; Post and Core Technique; Dental Cavity Preparation; Dental Materials; Root Canal Therapy
PubMed: 38750289
DOI: 10.1007/s00784-024-05720-4 -
The Bulletin of Tokyo Dental College May 2024In recent years, a wide variety of materials have been used in dental implant treatment. In selecting the superstructures and abutments to be used it is important to...
In recent years, a wide variety of materials have been used in dental implant treatment. In selecting the superstructures and abutments to be used it is important to consider their potential effect on the stability and durability of the planned implant. Excessive force applied to an implant during maintenance commonly results in complications, such as fracture of the superstructure or abutment, and loosening or fracture of the screws. This report describes a case of implant treatment for a 23-year-old man with esthetic disturbance due to trauma to the maxillary anterior teeth. The left maxillary central incisor could not be conserved due to this trauma, which had been caused by a traffic accident. After extraction, the tooth was restored with an anterior bridge. The crown of the left maxillary lateral incisor was fractured at the crown margin and, at the patient's request, implant treatment was selected as the restorative treatment for the missing tooth. A thorough preoperative examination was performed using placement simulation software. One titanium screw-type implant was placed in the maxillary left central incisor under local anesthesia. An all-ceramic crown with a zirconia frame was placed as a screw-fixed direct superstructure. At one year postoperatively, however, the superstructure and abutment became detached due to trauma. The fractured zirconia abutment was removed and replaced with a remanufactured abutment and superstructure. The patient has reported no subsequent dental complaint over the last 11 years. In this case, a surface analysis of the fractured zirconia abutment was performed. The scanned images revealed a difference in the fracture surfaces between the tensile and compressive sides, and electron probe microanalysis demonstrated the presence of titanium on the fracture surface. It was inferred that the hard zirconia abutment had scraped the titanium from the internal surface of the implant.
PubMed: 38749760
DOI: 10.2209/tdcpublication.2023-0028 -
Indian Journal of Dental Research :... Oct 2023Non-carious cervical lesions (NCCL) raise a considerable restorative challenge for the dentist in bonding, as adhesion is not as strong and predictable as enamel... (Comparative Study)
Comparative Study
INTRODUCTION
Non-carious cervical lesions (NCCL) raise a considerable restorative challenge for the dentist in bonding, as adhesion is not as strong and predictable as enamel bonding. A critical factor for restorative success is the selection of restorative material. Clinicians have tried many restorative materials and techniques to obtain the best performance. The aim of the present study was to evaluate and compare the clinical outcome of a Giomer and Resin modified glass ionomer cement (RMGIC) restoration in NCCL using united states public health service (USPHS) criteria at baseline, 3, 6 and 12 months.
MATERIALS AND METHOD
Patients from age 25 - 50 years having non-carious cervical lesions on both the sides and requiring restorations were screened. 20 patients were selected and further divided into 2 groups using simple random sampling technique. Group A- Beautifil II restoration using G-Premio bond (n = 10) and Group B- Ketac N100 restoration (n = 10). Restorations were done according to manufacturer's instructions and consequently evaluated at baseline, 3, 6 and 12 months using the USPHS criteria for marginal discolouration, marginal integrity, surface texture, colour match, gross fracture and post-operative sensitivity.
RESULTS
Giomer restorations showed better results than RMGIC. There was decrease in alpha ratings in both the study groups i.e., Giomer and RMGIC from 6 to 12 months.
DISCUSSION
The overall findings suggest that both Giomer and RMGIC gave satisfactory clinical results when used to restore non-carious cervical lesions. Both the materials can successfully be used since there was no statistically significant difference in the clinical outcome.
Topics: Humans; Glass Ionomer Cements; Dental Restoration, Permanent; Adult; Middle Aged; Tooth Cervix; Female; Resin Cements; Male; Dental Bonding
PubMed: 38739810
DOI: 10.4103/ijdr.IJDR_68_20 -
Journal of Prosthodontics : Official... May 2024To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access.
PURPOSE
To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access.
MATERIALS AND METHODS
Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05).
RESULTS
Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays.
CONCLUSION
The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.
PubMed: 38734932
DOI: 10.1111/jopr.13865 -
Materials (Basel, Switzerland) Apr 2024The aim of this paper was to evaluate the fracture resistance of 3D-printed zirconia occlusal veneers (OVs) of different thicknesses and supported by different abutment...
The aim of this paper was to evaluate the fracture resistance of 3D-printed zirconia occlusal veneers (OVs) of different thicknesses and supported by different abutment materials. The standard OV of a natural molar was prepared and digitized using a laboratory 3D scanner. The resulting digital tooth abutment was milled either using cobalt-chromium (CoCr) or a fiber-reinforced composite (FRC). All the abutments were digitized and standardized OVs (30° tilt of all the cusps) designed with 0.4 mm, 0.6 mm, or 0.8 mm wall thicknesses. The OVs were fabricated using either the Programill PM7 milling device (Ivoclar Vivadent, PM) or one of two 3D zirconia printers, Cerafab 7500 (Lithoz, LC) or Zipro-D (AON, ZD). The ZD samples were only tested on CoCr abutments. The completed OVs were luted to their abutments and subjected to artificial aging, consisting of thermocycling and chewing simulation before fracture testing with a steel sphere (d = 8 mm) as an antagonist with three contact points on the occlusal OV surface. Besides the total fracture resistance F, the lowest contact force F leading to the local fracture of a cusp was of interest. The possible effects of the factors fabrication approach, wall thickness, and abutment material were evaluated using ANOVA (α = 0.05; SPSS Ver.28). The total fracture resistance/contact forces leading to failure ranged from F = 416 ± 83 N/F = 140 ± 22 N for the 0.4 mm OVs fabricated using LC placed on the FRC abutments to F = 3309 ± 394 N (ZD)/F = 1206 ± 184 N (PM) for the 0.8 mm thick OVs on the CoCr abutments. All the factors (the fabrication approach, abutment material, and OV wall thickness) had an independent effect on F as well as F ( < 0.032). In pairwise comparisons for F of the OVs luted to the CoCr abutments, the ZD samples statistically outperformed the LC- and PM-fabricated teeth irrespective of the thickness ( < 0.001). Within the limitations of this study, the printed occlusal veneers exhibited comparable fracture resistances to those of the milled variants. However, more resilient abutments (FRC as a simulation of dentine) as well as a thinner wall thickness led to reduced OV fracture resistance, suggesting that 0.4 mm thick zirconia OVs should not be unreservedly used in every clinical situation.
PubMed: 38730928
DOI: 10.3390/ma17092122 -
Materials (Basel, Switzerland) Apr 2024Zirconia-reinforced lithium silicate (ZLS) is utilized as a material for prosthetic tooth crowns, offering enhanced strength compared to other dental glass-ceramics. In...
Zirconia-reinforced lithium silicate (ZLS) is utilized as a material for prosthetic tooth crowns, offering enhanced strength compared to other dental glass-ceramics. In this study, we investigate a commercial ZLS material, provided in a fully crystallized form. We examine the effects of an optional post-processing heat treatment on micro-contact damage using controlled indentation tests simulating the primary modes of contact during chewing: axial and sliding. Our findings indicate that the heat treatment does not affect mechanical properties such as the elastic modulus, hardness and indentation fracture toughness. However, it does enhance the resistance to contact damage by fracture and chipping in both axial and sliding modes, as well as the resistance to crack initiation measured from sliding tests. This improvement is attributed to the refinement of the flaw population achieved through the heat treatment. The results are analysed using principles of contact and fracture mechanics theory, discussing their significance in prosthetic dentistry.
PubMed: 38730767
DOI: 10.3390/ma17091961 -
Cureus Apr 2024Crown-root fractures are often challenging to treat and have a poor prognosis. The present case explains the successful management of a vertically fractured tooth...
Crown-root fractures are often challenging to treat and have a poor prognosis. The present case explains the successful management of a vertically fractured tooth treated by intentional replantation in a 12-year-old child. The patient underwent a successful 12-month follow-up, which included a mobility test and measurement of the gingival sulcus depth. Additionally, a radiological assessment was performed to evaluate the root resorption, the integrity of the alveolar cortex, and the periodontal space. We suggest that intentional replantation may be an effective therapeutic approach for the treatment of cases of vertical crown-root fractures.
PubMed: 38716028
DOI: 10.7759/cureus.57737 -
Cureus Apr 2024Dental trauma is one of the most prevalent problems encountered in clinical practice. Traumatic injuries involving fractures of the anterior tooth are one of the most... (Review)
Review
Dental trauma is one of the most prevalent problems encountered in clinical practice. Traumatic injuries involving fractures of the anterior tooth are one of the most common problems among children and adolescents. There is a physical and social impact on patients' quality of life due to traumatic dental injuries (TDIs). Children and adolescents frequently present with a crown fracture that necessitates immediate intervention. Clinicians need to be aware of various treatment modalities for TDIs and have to address these injuries immediately. Due to advances in adhesive technologies, fragment reattachment is the treatment of choice when the fragment is available and well stored. The purpose of this article is to cover various techniques for reattaching fractured fragments and the most current developments in adhesive systems for this purpose.
PubMed: 38711713
DOI: 10.7759/cureus.57715 -
Clinical Oral Investigations May 2024To assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival,...
OBJECTIVES
To assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival, complications (biological, technical) and quality.
MATERIAL AND METHODS
In a retrospective study, a total of 325 patients were recorded after up to 24.8 years (mean 13.9 ± 3.8 years) having (pre-)molars restored with CIO (Empress I, Ivoclar Vivadent, n = 161) and CGPC (Degunorm, DeguDent, n = 164) by supervised undergraduate students. A total of 296 restorations were assessed clinically and radiologically in healthy and endodontically treated teeth using modified United States Public Health Service (USPHS) criteria. Cumulative success and survival rates of the restorations were calculated using Kaplan-Meier estimates. Biological and technical complications were recorded. Status of oral health comprising caries risk and localized periodontitis were assessed.
RESULTS
The cumulative success rates of CIOs were 92.1% and of CGPCs 84.2% after mean service times of 14.5 years. The annual failure rates of total service times were 0.5% in teeth restored with CIO (n = 155) and 0.7% in teeth restored with CGPC (n = 163). The cumulative survival rates of CIOs were 93.9% after a mean service time of 15.2 years and decreased to 91.7% after 23.5 years. The cumulative survival rates of CGPCs were 92.6% after a mean service time of 14.9 years and 91.8% after 23.5 years. Complications in CIOs (n = 149) were ceramic fracture (6.7%), secondary caries (4.7%), endodontic complication (2.7%) and tooth fracture (1.3%) compared to CGPCs (n = 147) with endodontic complication (8.8%), secondary caries (4.8%) and decementation (2.0%). Endodontically treated teeth restored with CIO or CGPC revealed significantly less often success compared with corresponding vital teeth (p = .02). CIOs and CGPCs revealed clinically and radiographically good and excellent qualities with 71.8% (107/149) and 68% (100/147) without any significant differences regarding type of restoration.
CONCLUSIONS
Both CIOs and CGPCs achieved high survival rates up to 24.8 years when performed by supervised undergraduate students. The longevity of the restorations may benefit from the intraoral repair of accessible defects and, in case of pulp infection or necrosis, an adequate endodontic management.
CLINICAL RELEVANCE
CIOs and CGPCs made by supervised undergraduate students are proper restoration types in posterior teeth in the long-term. An adequate preparation design, meticulous care in the inserting technique and constant biofilm removal due to proper oral hygiene combined with professional maintenance care are substantial. The clinical long-term performance was mostly limited by ceramic fractures in CIOs and endodontic complications in CGPCs.
Topics: Humans; Retrospective Studies; Crowns; Dental Restoration Failure; Female; Male; Adult; Inlays; Ceramics; Gold Alloys; Dental Caries; Dental Porcelain; Middle Aged; Dental Prosthesis Design; Tooth, Nonvital; Treatment Outcome
PubMed: 38702521
DOI: 10.1007/s00784-024-05682-7