ABSTRACT
The choice of correct tooth shade for the fabrication of a restoration remains a challenge, even for experienced clinicians. The aim of this research was to evaluate and compare the precision of two different shade determination methods in terms of repeatability. Maxillary right central incisor of 10 patients was evaluated visually with the use of Vitapan Classical shade guide by five observers and instrumentally with the Vitapan classical shade guide values of ShadeEye NCC intra-oral colourimeter three times consecutively. The in vivo repeatability of methods were analysed with the spectrophotometric L*, a*, b* values of the shade guide (Vitapan Classical). Within the limitations of this study, the repeatability of instrumental (intra-oral dental colourimeter) and visual shade determinations were acceptable.
Subject(s)
Color/standards , Dental Prosthesis Design/instrumentation , Incisor/anatomy & histology , Adult , Color Perception , Colorimetry/instrumentation , Colorimetry/methods , Female , Humans , Male , Middle Aged , Observer Variation , Prosthesis Coloring/instrumentation , Reproducibility of Results , SpectrophotometryABSTRACT
The purpose of this study was to investigate occlusal schemes (canine guidance and group function) in relation to masticatory muscle activity. It was performed on 30 subjects, 15 with canine guidance and 15 with group function. Bilateral electromyographic recordings of masseter and anterior temporal muscles were obtained by surface electrodes during gum chewing and sliding laterally from centric relation while the teeth were in contact. The obtained data for both groups were compared statistically. Electromyograms were also evaluated visually. There was no significant difference in results between the occlusal schemes. However, canine guidance showed a narrower chewing model than group function and reduced anterior temporal muscle activity during sliding. This suggests that in the presence of healthy and good supportive canine teeth, canine guidance occlusion will be preferable.
Subject(s)
Dental Occlusion, Centric , Mastication/physiology , Masticatory Muscles/physiology , Adolescent , Adult , Bicuspid/physiology , Centric Relation , Cuspid/physiology , Electromyography , Female , Humans , Male , Reference ValuesABSTRACT
This study investigated the mandibular height reduction in relationship to aging and the length of edentulism period. Data were collected from 120 edentulous male subjects (complete denture wearers) who were divided into two resorptive age groups. The edentulism period of the subjects was classified as 1 to 5, 5 to 10, and over 10 years. Ridge resorption was estimated on the panoramic radiograph by estimating the original height of the alveolar process as being three times the distance from the inferior border of the mandible to the inferior edge of the mental foramen. According to statistical analysis, the amount of mandibular height reduction increased in the older age group. The mandibular resorption rate was greatest in the earlier stages of edentulism and slowed with longevity of edentulism.
Subject(s)
Alveolar Process/pathology , Denture, Complete/adverse effects , Mandibular Diseases/pathology , Mouth, Edentulous/pathology , Age Factors , Analysis of Variance , Humans , MaleABSTRACT
The objective of this study is to compare the marginal seal of Class II cavities restored with indirect inlays constructed on glass ionomer cement linings having different curing properties. Also the effect of acid-etching of these liners on microleakage was investigated. Mesio-occlusal and disto-occlusal cavities in 80 extracted human molars having the cervical floor below the cementoenamel junction were prepared (n:160). Half of the preparations were restored with Ceramco II porcelain and the rest with SR-Isosit resin inlay material. Liners as light curing Ionoseal light+chemically curing LCL 8 and Zionomer and chemically curing Ketac-Bond glass ionomer cements (GICs) were used. On mesial preparations GICs were acid-etched but were not on distal preparations. All inlays were cemented with Ultrabond composite material. After thermocycling the teeth were placed in a basic fuchsin dye solution for 24 h, then each tooth was sectioned. By using a stereomicroscope the extent of marginal leakage was scored and statistically evaluated. Microleakage was observed beneath all GIC linings and was more extensive between light curing GIC/dentine interface. By acid-etching of GICs the microleakage between GIC/dentine interface was increased significantly. Whether acid-etching was applied or not a significantly increased microleakage was recorded between chemically curing GIC/composite interfaces. Although the marginal microleakage was witnessed in both inlays, it appeared that porcelain inlays provided a better marginal seal, in comparison to SR-Isosit inlays.
Subject(s)
Acrylic Resins/chemistry , Composite Resins/chemistry , Dental Cavity Lining , Dental Leakage/diagnosis , Dental Porcelain/chemistry , Glass Ionomer Cements/chemistry , Inlays , Polyurethanes/chemistry , Acid Etching, Dental , Dental Cavity Preparation/classification , Dental Enamel/ultrastructure , Dental Polishing , Dentin/ultrastructure , Humans , Porosity , Surface PropertiesABSTRACT
The microleakage beneath porcelain laminate veneers was investigated. The restoration margins were located according to the preparations made below or above CEJ of extracted maxillary central incisors. Vitadur N and Microbond porcelain materials were used to prepare laminate veneers. A light cured composite resin (Porcelite) and a light- and chemical-cured composite resin (Porcelite Dual Cure) were used as luting agents. The bonded specimens were thermocycled and by employing the standard dye penetration technique, the leakage was scored from cervical and incisal margins. Significantly greater microleakage was recorded at the dentine composite resin interfaces than at the enamel/composite interfaces. Statistically insignificant differences were observed with the use of the four cement/porcelain combinations studied.
Subject(s)
Composite Resins/chemistry , Dental Cements/chemistry , Dental Leakage , Dental Porcelain/chemistry , Dental Veneers , Acid Etching, Dental , Aluminum Oxide/chemistry , Dental Bonding , Dental Cavity Preparation/methods , Dental Enamel/ultrastructure , Dental Leakage/diagnosis , Dentin/ultrastructure , Humans , Incisor , Materials Testing , Surface PropertiesABSTRACT
The effectiveness of two dentine-enamel bonding agents has been investigated in vitro when used together with an unfilled, low viscosity resin in eliminating the microleakage of porcelain laminate veneers. The restoration margins were located below and above the amelocemental junction of extracted maxillary central incisors. The bonded specimens were thermocycled and investigated for microleakage by employing a standard dye penetration technique. Leakage was scored at the cervical and incisal margins. Tenure was found more effective than Creation 3 in 1 in preventing leakage at both the cervical enamel and dentine/composite lute interfaces. With Tenure dentine bonding agent, the leakage observed at the cervical dentine/composite lute interface was found to be similar to that observed at the cervical enamel/composite lute interface. Sealing of finished veneer margins reduced the leakage at all interfaces.
Subject(s)
Dental Bonding/methods , Dental Leakage/prevention & control , Dental Veneers , Dental Enamel , Dental Porcelain , Dentin , HumansABSTRACT
The aim of this study was to evaluate the level of residual monomer in acrylic denture base materials having different polymerization properties. The investigation included a conventional-type acrylic cured under heat and pressure, as well as a pour-type resin polymerized by an injection-moulding technique at room temperature and under pressure. It was found that the residual monomer content ranged from 0.22-0.54% in pour-type resin, and from 0.23-0.52% in routinely used resins when the specimens were analysed by high performance liquid chromatography. These findings revealed that there were no significant differences between the two types of acrylic in terms of their residual monomer content.
Subject(s)
Acrylic Resins/chemistry , Denture Bases , Acrylic Resins/analysis , Chromatography, High Pressure Liquid , Evaluation Studies as Topic , Hot Temperature , Materials Testing , Polymers/chemistry , PressureABSTRACT
In this study, the effects of various enzymes to remove C. Albicans, contamined on to the different kinds of specimens prepared from 5 different denture base materials were investigated. All kinds of enzymes investigated were found to be effective, but both protase and the pure lipase were observed to be more effective than the others by their zero colonies calculated. It was decided that pepsin, trypsin and pancreatic amylase have less effects on C. Albicans than the others.
Subject(s)
Candida albicans/drug effects , Amylases/pharmacology , Denture Bases , Lipase/pharmacology , Pepsin A/pharmacology , Trypsin/pharmacologyABSTRACT
The fatigue behaviour of acrylic sheet specimens containing reinforcers were investigated. Three different kinds of reinforcers namely, stainless steel, aluminum reinforcer and three flex wire were used as strengtheners in acrylic resin sheets. The tests were carried out on alternating bending fatigue testing machine specially designed to test sheet specimens. By applying static and dynamic bending moments of any desired magnitude within the permissible capacity likits of the machine the fatigue lives of the specimens were determined. Experimental results showed that stainless steel strengtheners had a significant positive effect on the fatigue behaviour of acrylic resin.
