Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tooth Preparation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 523 records · Page 29Linked to original sources

Retentive force and microleakage of stainless steel crowns cemented with three different luting agents.

The aim of this investigation was to compare the tensile strength, microleakage, and Scanning Electron Microscope (SEM) evaluations of SSCs cemented using different adhesive cements on primary molars. Sixty-three extracted primary first molars were used. Tooth preparations were done. Crowns were altered and adapted for investigation purpose, and then cemented using glass ionomer cement (Aqua Meron), resin modified cement (RelyX Luting), and resin cement (Panavia F) on the prepared teeth. Samples were divided into two groups of 30 samples each for tensile strength and microleakage tests. The remaining three samples were used for SEM evaluation. Data were analyzed with one-way ANOVA and Tukey test. The statistical analysis of ANOVA revealed significant differences among the groups for both tensile strength and microleakage tests (p < 0.05). Tukey test showed statistically significant difference between Panavia F and RelyX Luting (p < 0.05), but none between the others (p > 0.05). This study showed that the higher the retentive force a crown possessed, the lower would be the possibility of microleakage.

Analysis of Variance↗

Initial in situ secondary caries formation: effect of various fluoride-containing restorative materials.

This study evaluated the effects of various restorative materials (Ariston pHc; Dyract; Vitremer; Tetric Ceram; Compoglass F, F2000; Hytac and Ketac Molar) on initial secondary caries formation in situ. Eighty-eight enamel slabs from sound human molars were sterilized (ethylene dioxide) and embedded in epoxy resin. Standardized tooth preparations were filled with the various restorative materials according to manufacturers' recommendations. One specimen from each group was inserted into one of two buccal aspects of an intraoral appliance worn by 11 volunteers for four weeks, day and night. Oral hygiene was performed without additional fluoride application. During meals and oral hygiene procedures, the appliances were stored in sucrose solution (10%). After in situ exposure, the samples were prepared for microradiographic assessment. Mineral content and lesion depth were evaluated by a dedicated software package (TMR 1.24). Lesion depth and mineral loss of the carious lesions close to Ariston pHc was significantly lower when compared to distant parts of the same lesions (p < 0.05; t-test, Bonferroni-Holm correction). All other materials containing fluoride showed no caries protective effect on surrounding enamel (p > 0.05; t-test, Bonferroni-Holm correction). A hydroxyl-, calcium- and fluoride-containing restorative material hampers demineralization next to the restoration, whereas, fluoride release of various fluoride-containing restorative materials does not affect demineralization of adjacent enamel in situ.

Adult↗

Two-year clinical performance of Class V resin-modified glass-lonomer and resin composite restorations.

While a one-year report had been previously published, this study was undertaken to evaluate the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over two years. Thirty-seven pairs of restorations of FujI II LC and Z 250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline, 6, 12, 18 and 24 months using modified Ryge/USPHS criteria. No statistically significant difference (p = 0.13) was observed in the overall performance of the materials. Retention was 96% for the resin-modified glass ionomer and 81% for the resin composite, with no additional restorations of either material lost after one year. As previously reported, retention of the Z 250 restorations at six months was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. The resin composite restorations generally had a better appearance, with a 100% alpha rating in color match, versus 85% for the resin-modified glass ionomer.

Adult↗

Mandibular ceramic veneers: an examination of complex cases.

The indications for mandibular anterior ceramic veneers, tooth preparation design, provisionalization considerations, and placement procedures were presented in a previous article by the author. The functional utility, tissue biocompatibility, and dissimilarities of mandibular veneers, in comparison to maxillary anterior ceramic veneers, were explored, along with indications and contraindications for this form of treatment. This article demonstrates the aesthetic range of these restorations in the context of more complex cases. The learning objective of this article is to illustrate the viability of mandibular ceramic veneers in realigning teeth nonorthodontically, while sustaining the biologic health of the periodontium, stability of the occlusion, and aesthetic parameters of each case. The importance of wax mock-ups is outlined for visualization of the final result, as well as the evaluation of root proximity to avoid subgingival ledging of the teeth and subsequent periodontal disease. Orthodontics and other methods for the correction of anterior crowding are discussed.

Composite Resins↗

Microleakage of resin-based liner materials and condensable composites using filled and unfilled adhesives.

PURPOSE: To evaluate the efficacy of differing resin based liner materials in reducing microleakage. METHODS: 80 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into two groups; each one was divided into four subgroups (A-B-C-D for Group 1 and E-F-G-H for Group 2). Each prepared tooth was etched with 32% H3PO4 (Uni Etch); in Group 1, one coat of One Step and in Group 2, two coats and two cures of Prime & Bond NT adhesives were applied. In each group 1 mm layer of three different liners was used: A2 Heliomolar RO for A and E; A2 Heliomolar Flow for B and F; A2 Bisfil 2B for C and G. No liner was used for D and H subgroups. Teeth were then restored using 2 mm increments of Pyramid A2 Dentin and A1 Enamel and cured with a VIP curing light. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x20 magnification. Dye penetration was scored using an Ordinal Scoring System where 0= no penetration; 1= enamel penetration; and 2= dentin penetration. RESULTS: A Chi Square Test revealed a statistically significant difference between Group 1 and Groups 2 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between the subgroups of each group; a statistically significant difference of B and D vs. E and H (P < 0.01 > 0.001) and B vs. G and D (P < 0.05 > 0.01) was also noted. The dentin bonding agent in Group 2 contributed to a reduction of microleakage when compared to Group 1.

Acid Etching, Dental↗

Patients' perception of lasers in dentistry.

BACKGROUND AND OBJECTIVE: Replacement of the dental handpiece (drill) has been of great interest in dentistry because of the overwhelming fear by patients to this method of tooth preparation. The driving force to find a replacement seems to be the undocumented requests of dental patients. Patients' perception of lasers and their ability to make a visit to the dentist easier is the focus of this study. STUDY DESIGN/MATERIALS AND METHODS: Surveys were given to 100 patients that questioned their perception of lasers. RESULTS: The survey showed that 69% of the responding patients thought that lasers would make their visit to the dentist easier. CONCLUSIONS: It seems that dental patients' perception of the laser is positive, and patients feel that lasers can make their visit to the dentist less traumatic.

Adult↗

Exposure of subgingival margins by nonsurgical gingival displacement.

A procedure has been outlined in which (1) gingival displacement is accomplished prior to subgingival tooth preparation and (2) the margins thus created can be very readily registered with commonly used elastic impression materials. Although the technique involves the placement of three cords, the benefits of better visibility and not having to cope with bleeding tissues result in a saving of time during the preparation appointment. The predictability of tissue contours results in fewer remakes and more esthetic and biologically acceptable restorations.

Colloids↗

Bond strength of three cements determined by centrifugal testing.

1. Each tooth preparation and crown should be used to test only one cement, since recementation will alter the bond strength associated with the second trial. 2. Recementation of a restoration should include a thorough cleaning of the preparation and the restoration. 3. Although zinc polycarboxylate cement possessed the highest bond strength, there were no statistically significant differences among the cements tested. 4. No correlation was found between bond strength and any individual property of compressive strength, tensile strength, or film thickness. 5. Values of ADA film thickness predicted the order of values of film thickness determined by a simulated clinical method.

Aluminum↗

A simplified approach to the complete porcelain margin.

The technique described produces a metal-ceramic crown exhibiting excellent esthetic qualities and marginal accuracy superior to that achieved on the cast metal margin. A platinum foil apron or refractory dies are not necessary. A precise shoulder preparation, preferably with two master dies, is required. A chamfer with a bevel, a shoulder with a bevel, or chamfer preparations are not suited to this technique. Quantitative evaluation using a measuring microscope showed that a marginal gap on a crown fabricated on an International Bureau of Standards crown die measured 6 microns at the porcelain shoulder and from 17 to 34 microns on a gold margin of the same crown. On a prepared-tooth, rubber-base compression densite die, the marginal gap on the porcelain shoulder was 10 microns.

Crowns↗

The upper anterior sectional denture.

An upper anterior sectional denture is described which consists of (1) a cast cobalt-chromium framework with two passive clasps that contact undercuts on the distal surfaces of the most posterior remaining teeth and (2) a labial flange that carries the replaced tooth or teeth and engages the labiointerproximal gingival undercuts of the anterior teeth adjacent to the edentulous ridge. The cast framework is inserted occlusogingivally, and the labial flange is inserted labiolingually. Both sections are held together by the frictional resistance of the split post of the framework that fits into a tube on the labial flange and hollowed-out artificial tooth. With this type of prosthesis, certain clinical problems can be handled without abutment tooth preparation and with a minimal amount of chair time.

Adult↗

Self-threading pin penetration into dentin.

A laboratory study has shown that the first-half of self-shearing 2-in-1 self-threading pins, sizes 0.031 inch and 0.024 inch, fail to reach full channel depth when placed with either a hand wrench or an Auto Klutch handpiece. The average discrepancy of penetration is about 0.75 mm. This discrepancy in seating results in a significant excess pin length extending into the tooth preparation, which compromises the strength characteristics of the amalgam restoration.

Dental Amalgam↗

Fabricating crowns to fit clasp-bearing abutment teeth.

As with other direct-indirect methods, the Duralay index method has the advantage of not depriving patients of their dentures. The index takes very little time to fabricate since it is only necessary to obtain a Duralay mold of the internal surface of the clasp assembly and the external surface of the prepared tooth. In addition, the index will serve as a guide for the final waxup. In waxing, it will only be necessary to fill in the contours and margins without touching the index surfaces which contact the clasp assembly and occlusal stops. If occlusal stops were incorporated in the index, no opposing cast is necessary. This method may be used with full veneer and veneered crowns and any impression technique and die material providing that the expansion during investing and casting results in a passive fit of the crown.

Acrylic Resins↗

A comparison of cord gingival displacement with the gingitage technique.

Fifteen young adult dogs were divided into three groups representing 0, 7- and 21-day healing periods. Randomly selected cuspid teeth were used to compare cord gingival displacement and gingitage techniques for subgingival tooth preparation and impression making. Clinical and histologic measurements were used as a basis for comparison. Results indicate that (1) the experimental teeth were clinically healthy at the beginning of the experiment, (2) clinical health of the gingival tissues was controlled throughout the course of the experiment, and (3) within this experimental setting, there was no significant difference between the cord gingival displacement technique and the gingitage technique.

Animals↗

Crown contours and gingival response.

The following periodontal/restorative interrelations should be observed: 1. Deflective contours and/or overcontouring should be avoided in the cervical third and the interproximal surfaces of tooth restorations. 2. Overcontouring of the interproximal region is common and harmful to periodontal health. 3. Adequate tooth reduction at the gingival margin and interproximally provides for restorative materials and lessens the potential for overcontouring in these critical regions. 4. Fluting or barreling of exposed furcations eliminates plaque shelves and promotes accessibility for hygiene. 5. Minimal disruption within the intracrevicular space during tooth preparation allows a more predictable, favorable periodontal response to satisfactorily contoured restorations.

Crowns↗

The effects of die relief agent on the retention of full coverage castings.

The effect of a commercial die relief agent on the retention of castings cemented with a zinc phosphate, a zinc polycarboxylate, or a modified zinc oxide-eugenol cement was studied. Forces required to dislodge unspaced castings from tooth preparations were higher when zinc phosphate cement was the luting medium. Die relief agents resulted in a 32% reduction in the forces required to dislodge castings cemented with zinc phosphate. Data for the other cements did not differ statistically. Shear strength-tensile ratios of the cements indicate that the high shear strength provided by zinc phosphate cement may be negated by the cementation of oversize castings fabricated from relieved dies.

Crowns↗

Recent advances in etched cast restorations.

This article described the etched cast restoration. The advantages, disadvantages, indications, contraindications, and technique were discussed. The rationale for modifications in the original framework design and tooth preparation was also presented; some unique advantages over traditional fixed prosthodontics are provided. A retentive framework with maximum coverage is recommended until research expands and simplifies the technique.

Acid Etching, Dental↗

Impression material thickness in stock and custom trays.

This study did not examine the accuracy of the resultant impressions. Rather, the impression material thickness in impressions made using both the highly advocated custom acrylic resin tray and in the highly used manufactured stock tray was examined. Comparison between the material thickness at the prepared tooth area revealed a mean difference in material thickness of less than 1 mm. The question of the significance of this difference remains to be answered. If the difference is not significant in the success of the impression and the resultant casting, then there are several advantages in using the manufactured stock tray; the first is economy. The average cost of a custom acrylic full arch impression tray is $3.65, compared with an average cost of slightly over $0.30 for the stock tray. The second advantage is the convenience factor. Making a custom tray requires planning, study models, laboratory time, curing interval, and finishing time. In contrast, the stock tray can be selected, adapted, and used in a single visit for both anticipated and unanticipated situations. If the difference in material thickness is significant, the custom tray is indicated. However, attention to detail in making and inserting the tray in the mouth must be observed to maximize the benefits of the custom tray.

Acrylic Resins↗

Changes of attitude in fixed prosthodontic patients.

The results of a survey that examined the perceptions and attitudes of patients who have completed fixed prosthodontic treatment were described. The data obtained in this survey confirm the clinical experiences of many restorative dentists. Most patients desire functional, comfortable, and particularly, esthetic restorations. They are sensitive to changes that occur when provisional restorations are replaced by definitive crowns and fixed partial dentures. Tooth preparation and impression procedures are perceived as the most unpleasant steps in the treatment process. On completion of treatment, patients recognize and appreciate its benefits. The data have implications for the overall treatment process. With an appreciation for the perceptions and attitudes of fixed prosthodontic patients, the restorative dentist is prepared more completely to provide satisfying restorations. Through increased awareness of patient expectations and experiences, restorations can be planned, made and placed in harmony with the hard and soft oral tissues, and in harmony with the patient's expectations as well.

Adolescent↗