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Journal of the Mechanical Behavior of... Oct 2023The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of...
PURPOSE
The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of polymerization-induced cracks, and tooth deformation of structurally compromised molars restored with lithium disilicate inlays and overlays in combination with Immediate Dentin Sealing (IDS).
MATERIAL AND METHODS
Human molars (N = 64) were randomly assigned to four different preparation designs: Undermined Inlay (UI), Extended Inlay (EI), Restricted Overlay (RO), and Extended Overlay (EO). The teeth were restored using lithium disilicate partial restorations and subjected to thermomechanical fatigue in a chewing simulator (1,2 × 10 (Mondelli et al., 2007) cycles on 50 N, 8000x 5-55 °C), followed by load to failure testing. In silico finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. Fracture strengths were statistically analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using Fisher exact test.
RESULTS
The propagation of polymerization-induced cracks did not significantly differ among preparation designs. All specimens withstood chewing simulator fatigue, with no visible cracks in teeth or restorations. Fracture strength was significantly influenced by preparation design, with restricted overlay (RO) showing higher fracture strength compared to extended inlay (EI) (p = .042). Tooth deformation and fracture resistance correlated between in vitro and in silico analyses). UI exhibited a statistically less destructive failure pattern than EO (p < .01) and RO (p = .036). No statistically significant influence of the preparation design on repairability was observed. Groups with higher repairability rates experienced increased tooth deformation, leading to less catastrophic failures.
CONCLUSIONS
The preparation design affected the fracture strength of compromised molars restored with lithium disilicate inlays and overlays, with significantly lower fracture strength for an extended inlay. The failure pattern of lithium disilicate overlays is significantly more destructive than that of undermined and extended inlays. The finite element analysis showed more tooth deformation in the inlay restorations, with lower forces in the roots, leading to less destructive fractures. Since cusp coverage restorations fracture in a more destructive manner, this study suggests the undermined inlay preparation design as a viable option for restoring weakened cusps.
Topics: Humans; Flexural Strength; Molar; Dental Porcelain; Fatigue; Fractures, Bone
PubMed: 37659167
DOI: 10.1016/j.jmbbm.2023.106096 -
The American Journal of Dental Science May 1896
PubMed: 30757608
DOI: No ID Found -
Journal of Ophthalmic & Vision Research 2017Presbyopia is the primary cause of reduction in the quality of life of people in their 40s, due to dependence on spectacles. Therefore, presbyopia correction has become... (Review)
Review
Presbyopia is the primary cause of reduction in the quality of life of people in their 40s, due to dependence on spectacles. Therefore, presbyopia correction has become an evolving and rapidly progressive field in refractive surgery. There are two primary options for presbyopia correction: the dynamic approach uses the residual accommodative capacity of the eye, and the static approach attempts to enhance the depth of focus of the optical system. The dynamic approach attempts to reverse suspected pathophysiologic changes. Dynamic approaches such as accommodative intraocular lenses (IOLs), scleral expansion techniques, refilling, and photodisruption of the crystalline lens have attracted less clinical interest due to inconsistent results and the complexity of the techniques. We have reviewed the most popular static techniques in presbyopia surgery, including multifocal IOLs, PresbyLASIK, and corneal inlays, but we should emphasize that these techniques are very different from the physiologic status of an untouched eye. A systematic PubMed search for the keywords "presbylasik", "multifocal IOL", and "presbyopic corneal inlay" revealed 634 articles; 124 were controlled clinical trials, 95 were published in the previous 10 years, and 78 were English with available full text. We reviewed the abstracts and rejected the unrelated articles; other references were included as needed. This narrative review compares different treatments according to available information on the optical basis of each treatment modality, including the clinical outcomes such as near, intermediate, and far visual acuity, spectacles independence, quality of vision, and dysphotopic phenomena.
PubMed: 29090052
DOI: 10.4103/jovr.jovr_162_16 -
Eye and Vision (London, England) 2018Presbyopia corrections traditionally have been approached with attempts to exchange power, either at the cornea or the lens planes, inducing multifocality, or altering... (Review)
Review
Presbyopia corrections traditionally have been approached with attempts to exchange power, either at the cornea or the lens planes, inducing multifocality, or altering asphericity to impact the optical system. Treatments that affect the visual axis, such as spectacle and contact lens correction, refractive surgeries, corneal onlays and inlays, and intraocular lenses are typically unable to restore true accommodation to the presbyopic eye. Their aim is instead to enhance 'pseudoaccommodation' by facilitating an extended depth-of-focus for which vision is sufficient. There is a true lack of technology that approaches presbyopia from a treatment based or therapy based solution, rather than a 'vision correction' solution that compromises other components of the optical system. Scleral surgical procedures seek to restore true accommodation combined with pseudoaccommodation and have several advantages over other more invasive options to treat presbyopia. While the theoretical justification of scleral surgical procedures remains controversial, there has nevertheless been increasing interest and evidence to support scleral surgical and therapeutic approaches to treat presbyopia. Enormous progress in scleral surgery techniques and understanding of the mechanisms of action have been achieved since the 1970s, and this remains an active area of research. In this article, we discuss the historic scleral surgical procedures, the two scleral procedures currently available, as well as an outlook of the future for the scleral surgical space for treating presbyopia.
PubMed: 29497624
DOI: 10.1186/s40662-018-0098-x -
BMC Oral Health Sep 2022This study aims to evaluate the association between smoking habits and dental care utilization and cost in individuals registered with the Japan Health Insurance...
BACKGROUND
This study aims to evaluate the association between smoking habits and dental care utilization and cost in individuals registered with the Japan Health Insurance Association, Osaka branch.
METHODS
We used the administrative claims database and specific medical check-up data and included 226,359 participants, who visited dental institutions, underwent dental examinations, and underwent specific medical checkups, with smoking data from April 2016 to March 2017. We calculated propensity scores with age, gender, exercise, eating habits, alcohol intake, and sleep. We also compared dental care utilization with the total cost of each procedure.
RESULTS
According to propensity score matching, 62,692 participants were selected for each group. Compared to non-smokers, smokers were younger, and a higher proportion were men. Smokers tended to skip breakfast, have dinner just before bed, and drink alcohol. After adjusting for potential confounding factors with propensity score matching, the mean annual dental cost among smokers was significantly higher than non-smokers. The prevalence of pulpitis, missing teeth, and apical periodontitis were higher among smokers than non-smokers, while inlay detachment, caries, and dentine hypersensitivity were higher among non-smokers.
CONCLUSION
This study suggests that smokers have higher dental cost consisted of progressive dental caries, missing teeth, and uncontrolled acute inflammation that necessitated the use of medications. It is suggested that smokers tend to visit the dentist after their symptoms become severe.
Topics: Alcohol Drinking; Dental Care; Dental Caries; Female; Humans; Male; Smokers; Smoking
PubMed: 36056338
DOI: 10.1186/s12903-022-02397-7 -
Dental Materials Journal Jan 2023This review describes the development of ultra-high translucent zirconia (referred to as UHTZ) using new manufacturing technology and its characterization results. The... (Review)
Review
This review describes the development of ultra-high translucent zirconia (referred to as UHTZ) using new manufacturing technology and its characterization results. The development of UHTZ was primarily due to the adoption of two basic manufacturing technologies, "Cyclic CIP" and "Plus Y Technology". This manufacturing technology could provide stable processing characteristics, which improves chipping resistance during milling. Furthermore, the enlargement factor (processing coefficient) for UHTZ is smaller than those for conventional products. In general, the higher the light transmittance, the lower the flexural strength. Despite its extremely high translucency, the most significant feature of UTHZ is that its flexural strength is comparable to that of 5Y. Furthermore, UHTZ has higher chemical durability and uniform microstructure, which results in less wear on the opposing teeth and superior discoloration resistance. Therefore, UHTZ is a new option for inlay, onlay, and laminate veneer applications, where lithium disilicate glass ceramics has been widely used.
Topics: Materials Testing; Dental Porcelain; Ceramics; Zirconium; Flexural Strength; Surface Properties
PubMed: 36631076
DOI: 10.4012/dmj.2022-243 -
Materials (Basel, Switzerland) Sep 2021The purpose of this study is to identify the stress levels that act in inlay and onlay restorations, according to the direction and value of the external force applied....
The purpose of this study is to identify the stress levels that act in inlay and onlay restorations, according to the direction and value of the external force applied. The study was conducted using the Finite Element Method (FEM) of three types of ceramics: pressed lithium disilicate and monolith, zirconia, and three different adhesive systems: self-adhesive, universal, and dual-cure cements. In addition to FEM, the inlay/onlay-dental structure interface analysis was performed by means of Scanning Electron Microscopy (SEM). The geometric models were reconstructed based on computer tomography images of an undamaged molar followed by geometrical procedures of inducing the inlay and onlay reconstructions. The two functional models were then simulated for different orientations of external force and different material properties, according to the considered adhesives and ceramics. The Scanning Electron Microscopy (SEM) was conducted on 30 extracted teeth, divided into three groups according to the adhesive cement type. Both FEM simulation and SEM investigations reveal very good mechanical behavior of the adhesive-dental structure and adhesive-ceramic interfaces for inlay and onlay reconstructions. All results lead to the conclusion that a physiological mastication force applied, regardless of direction, cannot produce a mechanical failure of either inlay or onlay reconstructions. The adhesive bond between the restorations and the dental structure can stabilize the ceramic restorations, resulting in a higher strength to the action of external forces.
PubMed: 34501143
DOI: 10.3390/ma14175048 -
Journal of Ophthalmology 2016Purpose. The purpose of this review is to provide a summary of laser refractive surgery and corneal inlay approaches to treat presbyopia in patients after cataract... (Review)
Review
Purpose. The purpose of this review is to provide a summary of laser refractive surgery and corneal inlay approaches to treat presbyopia in patients after cataract surgery. Summary. The presbyopic population is growing rapidly along with increasing demands for spectacle independence. This review will focus on the corneal-based surgical options to address presbyopia including various types of corneal intrastromal inlays and laser ablation techniques to generate either a multifocal cornea ("PresbyLASIK") or monovision. The natural history of presbyopia develops prior to cataracts, and these presbyopic surgeries have been largely studied in phakic patients. Nevertheless, pseudophakic patients may also undergo these presbyopia-compensating procedures for enhanced quality of life. This review examines the published reports that apply these technologies to patients after cataract surgery and discusses unique considerations for this population.
PubMed: 27051527
DOI: 10.1155/2016/5263870 -
Journal of Pharmacy & Bioallied Sciences Jul 2022The extensively damaged teeth can be treated with the inlay and onlay. The ceramic inlays and onlays can be prescribed for the esthetic needs of the patient. Hence in...
INTRODUCTION
The extensively damaged teeth can be treated with the inlay and onlay. The ceramic inlays and onlays can be prescribed for the esthetic needs of the patient. Hence in our study, we aim to evaluate clinically the outcomes of the ceramic inlays and onlays for the posterior teeth.
MATERIALS AND METHODS
We piloted a retrospective analytical study from the departmental records. We included 70 patients who had a total of 160 ceramic inlays and onlays prepared between the years 2010-2020. The survival and the failure rates were noted and compared using the "Kruskal-Wallis H statistics and the Chi-square tests" deliberating < 0.05 as significant.
RESULTS
The mean survival was 6.1 ± 1.8 years. The success rate was 92.21% and the failure was 7.6%. Significant variation was seen with the survival rate between the vital and nonvital teeth and between the molars and premolars.
CONCLUSIONS
The ceramic inlays and onlays were performed successfully in the posterior teeth with a high survival rate and very low failure.
PubMed: 36110720
DOI: 10.4103/jpbs.jpbs_776_21 -
Clinical & Experimental Optometry Jan 2008This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant... (Review)
Review
This review is based on the activities of the Vision Cooperative Research Centre (previously Cooperative Research Centre for Eye Research and Technology) Corneal Implant team from 1991 to 2007. The development of a synthetic polymer of perfluoropolyether (PFPE), meeting essential physical and biological requirements, for use as a corneal inlay is presented. Each inlay was placed in a corneal flap created with a microkeratome and monitored over a two-year period in a rabbit model. The results indicate that the PFPE implant shows excellent biocompatibility and biostability. As a result, a Phase 1 clinical trial is being conducted. Three years post-implantation, the PFPE inlays are exhibiting continued excellent biocompatibility. Corneal inlays made from PFPE are biocompatible with corneal tissue in the long term and offer a safe and biologically-acceptable alternative to other forms of refractive surgery.
Topics: Animals; Biocompatible Materials; Cornea; Humans; Myopia; Prostheses and Implants; Prosthesis Design; Prosthesis Implantation; Treatment Outcome
PubMed: 18045251
DOI: 10.1111/j.1444-0938.2007.00198.x