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 973 records · Page 54Linked to original sources
PubMed1993

In vitro posterior composite polymerization recovery following hygroscopic expansion.

Post-operative pain has been associated with composite polymerization shrinkage. This study aimed to quantify the cuspal deflection resulting from the initial shrinkage and the subsequent hygroscopic expansion of a standard posterior composite resin. Thirty hydrated permanent molars were marked on the buccal and lingual cusp tips. Standardized conventional Class II preparations were made and restorations with composite resin were placed and: (A) polymerized as one complete unit; (B) polymerized in gingivo-occlusal increments; (C) polymerized in buccolingual increments. Ten untreated teeth were marked and acted as controls. All specimens were placed in water. Pre-operative, post-operative and 6-month photographs were projected on a digitizer pad and measured by two independent investigators. The mean cuspal deflection (micron) immediately post-operatively and 6 months respectively, was: (A) 22.4, 8.7; (B) 12.4, 5.3; (C) 9.8, 3.0. The percentage of natural tooth dimensional recovery, following hygroscopic expansion was: (A) 97.5%; (B) 98.6%; (C) 99.4%. Buccolingual incremental polymerization led to significantly less initial cuspal deflection and the most cuspal recovery after hygroscopic expansion. The technique of resin placement therefore may provide a decrease in post-operative sensitivity.

Composite Resins↗
PubMed2001

Stresses within porcelain veneers and the composite lute using different preparation designs.

PURPOSE: The purpose of this study was to investigate compressive and tensile stresses in porcelain and composite at the labial marginal region of porcelain veneer restorations using chamfer, shoulder, or knife-edge labial margin designs with labial window or incisal overlap incisal preparation designs. METHODS: Porcelain veneer models were constructed and loaded with (1) a 200-N, 45 degrees palatal load to simulate functional loading, and (2) a horizontal labial loading of 200 N to mimic trauma. Maximum tensile and compressive stresses were recorded within the labial marginal region of both porcelain and composite lute. RESULTS: Under the 45 degrees palatal load, stresses within the palatal marginal porcelain were chiefly compressive, and stresses for the knife-edge designs as much as 42% less than for shoulder designs. Incisal overlap preparations were generally associated with less compressive stress within both porcelain and composite than the window preparation. When a labial load was applied, tensile stresses were as much as 25 times greater for the chamfer and shoulder designs compared with the knife-edge design. Labial loading also resulted in an increase in tensile stresses within the composite lute, and stresses were again lowest within the knife-edge margin design. CONCLUSIONS: Under the limitations of this study, using the incisal overlap preparation, porcelain veneers with knife-edge labial margins could better sustain occlusal loading without fracture. J Prosthodont 2001;10:16-21.

Bite Force↗
PubMed2006

[Examination of cardiovascular function variables in tooth extraction under local anesthesia].

BACKGROUND/AIM: Local anesthesia is the one of the most used procedures in surgical practice. It is used for toot extraction to produce analgesic and anesthetic effects. However, there is a question if it is equally safe to apply a local anesthetic combined with a vasoconstrictor (adrenaline) in healthy persons, and in the patients with a certain cardiovasccular system disease. The aim of this stady was to determine whether there were differences in cardiovascular variables during tooth extraction in healthy persons, and in cardiovascular patients when an anesthetic was applyted with adrenaline, or without it. METHODS: The examinees were divided into the group with cardiovascular diseases (CV, n=57) of H and III type, according to the American Society of Anesthesiologists (ASA) qualification, and healthy persons (H, n=55). Both groups were randomly divided into two subgroups: CVa and Ha--where the anesthetic solution had the vasoconstrictor (3% lidocaine, and 1: 100,000 adrenaline); CVb and Hb--where the anesthetic solution was without the vasoconstrictor (3% lidocaine). During the preparation for tooth extraction, the application of anesthetics, extraction and relaxation puls (fc), systolic (TAs) and diastolic arterial blood pressure (TAd) and ECG were registered. RESULTS: The values of fc did not significantly differ among the groups in any measured term. The values of systolic and diastolic blood pressure in the groups CVa and CVb were significantly higher in all the terms of measuring (p < 0.05) from the values in the groups Ha and Hb. A significant increase of TAs was registered only in the phase of tooth extraction in the CVa and CVb group (< 0.05). The values of TAd did not significantly differ between the groups in all the measured terms. Extrasystolic beats were registered in 11 patients of the CV group and in 7 patients of the H group in the phase of anesthetic application or tooth extraction. CONCLUSION: This research shoved that tooth extraction under local anesthesia did not cause complications in cardiovascular patients who were in II or III ASA qualification group, regardless the presence of a vasoconstrictor in the local anesthetic solution.

Adult↗
PubMed1999

Treatment of root perforation by intentional reimplantation: a case report.

Intentional reimplantation is defined as a procedure in which an intentional tooth extraction is performed followed by reinsertion of the extracted tooth into its own alveolus. In this paper, intentional reimplantation is described and discussed as a treatment approach to root canal instrument separation in conjunction with root perforation. An 8-year follow-up case report is presented. The reimplanted tooth is now a fixed bridge abutment. Although successful in this case, the intentional reimplantation procedure should be considered a treatment of last resort, that is, when another treatment option is not viable for the treatment of root perforation/instrument retrieval.

Adult↗
PubMed1997

[Dental restoration materials in pediatric dentistry].

Restorative materials in pediatric dentistry have to fulfill special requirements. They should be easy to handle and applicable in a not always dry mouth. They should potentially be adhesive in order to avoid too much mechanical preparation. They do not have to be extremely wear resistant as the dwell time of the restorations is relatively short. Glass-ionomer cements and in particular the resin modified types possess properties which make them almost ideal for the required purpose.

Child↗
PubMedDate not supplied

Clinical aspects of all-ceramic CAD/CAM restorations.

All-ceramic restorations were restricted in the past to a relatively small group of users. Among other things, this is explained by the high clinical expense for such work. The latter can be reduced decisively by using high-strength hard core ceramics and CAD/CAM production. The preparation corresponds largely to the preparation in metal-ceramic work. There are also scarcely any differences in elastic impression taking. Thanks to the high strength of modern all-ceramic systems, they can be inserted conventionally; using adhesive systems is naturally also possible and recommended.

Cementation↗
PubMed2006

Removable partial denture abutments restored with all-ceramic surveyed crowns.

All-ceramic crowns are used as alternatives to conventional metal-ceramic crowns for the restoration of single teeth. Traditionally all-ceramic restorations possessed physical properties that contraindicated their use in many treatment situations. The strength that zirconia ceramics exhibit seems to support the hypothesis that, in specific situations, an all-ceramic crown may be used to restore removable partial denture (RPD) abutments in areas previously reserved for metal or metal-ceramic restorations. Abutments for RPDs may now be fabricated with Procera AllZirkon with the classically prepared guide planes and rest seats. This article provides an overview of a technique for the fabrication of a zirconia-based crown to be used in conjunction with removable partial dentures using the Procera CAD/CAM technology.

Ceramics↗
PubMedDate not supplied

Influence of timing of coronal preparation on retention of cemented cast posts and cores.

PURPOSE: This study investigated the effect of coronal preparation by high-speed handpiece on the retention of cemented cast posts and cores. MATERIALS AND METHODS: Cast posts and cores were fabricated for 90 extracted single-rooted human teeth cemented with zinc-phosphate cement and randomly divided into six groups of 15 specimens each. The six groups were matched randomly two by two, such that one of each of the matched groups was subjected to a 4-minute period of high-speed preparation of the cores. Castings from the first pair (1 and 2) were subjected to an axially directed removal force using a universal testing machine 15 minutes from the start of cement mixing; castings from the second (3 and 4) and third (5 and 6) pairs were tested at 1 hour and 24 hours, respectively, having been stored in water at 37 degrees C for the waiting periods. The forces required for dislodgment of posts from their prepared spaces were recorded. Data were statistically analyzed using two- and one-way ANOVA and the Student's t test. RESULTS: The results showed increased mean retentive strengths of posts as the time to testing increased for both unprepared and prepared groups. Significantly higher mean retentive strengths of posts were recorded for unprepared compared to prepared groups tested at 15 minutes and 1 hour after cementation. CONCLUSION: High-speed preparation had a significant negative effect on the retentive strengths of posts tested at 15 minutes and 1 hour after cementation, but not on those tested at 24 hours.

Analysis of Variance↗
PubMedDate not supplied

Survival of ceramic computer-aided design/manufacturing crowns bonded to preparations with reduced macroretention geometry.

PURPOSE: Adhesive cementation reduces the need for macroretentive preparation for crowns. This study investigated the survival and clinical rating of monolithic computer-aided design/manufacturing (CAD/CAM) ceramic crowns bonded to preparations with reduced macroretention, hypothesizing that adhesion would compensate for reduced retention geometry. MATERIALS AND METHODS: Two-hundred eight posterior CAD/CAM-generated crowns from feldspar block ceramic were adhesively bonded in 136 patients in three preparation groups: classic (100% stump height, n = 70); reduced (reduced stump height or irregular stump, n = 52); and endo (absent stump but pulp chamber retention cavity, n = 86). Crowns were examined at baseline and after 55 +/- 15 months using modified USPHS criteria. Plaque and bleeding of gingiva around the crowns were assessed. RESULTS: Cumulative Kaplan-Meier survival of crowns on premolars/molars was: classic = 97.0%/94.6%; reduced = 92.9%/92.1%; and endo = 68.8%/87.1%, confirming the hypothesis for classic, reduced, and endo molars as well as for classic and reduced premolars. A significant difference was found between classic and endo premolar crowns, rejecting the hypothesis for endo preparation on premolars. Plaque and bleeding indices were significantly lower for crowned teeth than for controls. CONCLUSION: The survival of classic and reduced crowns was rated adequate for premolars and molars. Endo preparation appeared acceptable for molar crowns but inadequate for premolar crowns.

Aluminum Silicates↗
PubMed1996

Preparation of guide planes using a reciprocating handpiece.

A reciprocating handpiece and attachments have been found effective in preparing guide planes prior to the construction of removable partial dentures. A comparison was made of the enamel surface prepared using the reciprocating handpiece and a conventional rotary handpiece. Two-stage and three-stage techniques for each handpiece were compared. Scanning electron micrographs showed that a smoother surface was created by the reciprocating handpiece.

Bicuspid↗
PubMedDate not supplied

Comparative study of microleakage of a pit and fissure sealant placed after preparation by Er:YAG laser in permanent molars.

PURPOSE: The aim of this study was to assess the microleakage of a pit and fissure sealant on enamel treated with a laser, with and without etching. METHODS: Sixty non-carious extracted molars were randomly assigned to 2 groups. For both groups, in the mesial halves, the fissures were widened mechanically with a bur and etched for 15 seconds. In group 1, the distal half was prepared with a laser alone; in group 2, a laser was followed by etching. Then the sealant was applied on all teeth. RESULTS: Laser alone showed the highest number of specimens with microleakage (63%) (P < .02) and the highest mean of microleakage (0.76 mm vs 0.12 mm, 0.17 mm, and 0.18 mm; P < .01). CONCLUSIONS: No significant difference was noted between the 2 types of enamel preparation when etching was performed. Laser irradiation did not eliminate the need for etching the enamel surface before applying the sealant.

Acid Etching, Dental↗
PubMedDate not supplied

5-year follow-up of a prospective clinical study on various types of core restorations.

PURPOSE: This study tested whether: (1) the survival rate of cast post-and-core restorations is better than the survival of direct post-and-core restorations and post-free all-composite cores; and (2)the survival of these buildup restorations is influenced by the remaining dentin height after preparation. MATERIALS AND METHODS: In a clinical trial, 18 operators made 319 core restorations in 249 patients. The restorations involved were: (1) cast post-and-core restorations; (2) direct post and composite core restorations; and (3) post-free all-composite cores. All restorations were made under single porcelain-fused-to-metal crowns. Treatments were allocated after dentin height assessment using balanced drawing. Failures were registered during a 5-year period. RESULTS: Fifteen restorations failed during the follow-up period. Five failures occurred during the first month; they were considered to be independent from clinical aging and excluded from further survival assessments. The overall survival was 96%+/-2%. No difference was found between the survivals of the different types of restorations. The factor "remaining dentin height" appeared to have a significant effect on the survival of post-and-core restorations (98%+/-2% survival for "substantial dentin height" vs 93%+/-3% for "minimal dentin height"). CONCLUSION: The type of post and core was not relevant with respect to survival. The amount of remaining dentin height after preparation influenced the longevity of a post-and-core restoration.

Adolescent↗
PubMed1993

Acute toxicological effects of ingested tooth whiteners in female rats.

Tooth whiteners are considered as cosmetic agents to be used for bleaching teeth. Since tooth whitener may be swallowed during the whitening procedure, studies were conducted to determine whether ingestion of tooth whitener containing carbamide peroxide resulted in toxic effects. Adult female rats were used, and vaginal smears were examined daily to determine whether the animals were ovulating. Following an overnight fast, a single bolus of a commercial tooth whitener (5 g of tooth whitener/kg fasting body weight) was administered by gavage. Control rats received de-ionized water. After 2 h, mean respirations per min of animals receiving the tooth whitener Quik Start (contains 35% carbamide peroxide) decreased from 169 to 55, and body temperature decreased from 38.4 to 34 degrees C. Other distress signs included: labored breathing, loss of righting reflex, partial eye closure, bloody urine, and incontinence. Three of 22 animals (3/22) died within 48 h, of gastric hemorrhaging. Eight/10 rats stopped ovulating. At necropsy 2 weeks post-dosing, 10/19 animals had grossly bloated stomachs, and mucosal necrosis was observed histologically in 3. Animals receiving White & Brite or Nu-Smile (containing 10 or 15% carbamide peroxide, respectively) exhibited similar but milder symptoms. The data indicate that ingestion of large doses of commercial preparations of tooth whiteners may be acutely toxic, sometimes fatal, to female laboratory rats.

Animals↗
PubMed1997

Accuracy of apex locator.

An evaluation of the accuracy of the "Root ZX" apex locator was conducted on 20 single-rooted teeth that had been extracted because of severe disease or orthodontic treatment. After the pulp chamber had been accessed and the tooth length determined using the Root ZX apparatus, the file was fixed to the tooth with light-cured composite resin. After extraction, the tooth was longitudinally ground with a diamond bur until the file was visible. The distance between the file tip and the apical foramen was measured under a microscope (x 100). The results showed that the tip of the instrument reached the apical foramen in all teeth.

Adult↗
PubMed1990

Clinical behaviour of high-copper amalgams with time, site, size and class of cavity preparation.

In this study 767 amalgam restorations placed in the posterior permanent teeth of 122 patients were evaluated at 6-monthly intervals up to 2 years. Six commercially available high-copper alloy amalgams were assessed for surface roughness, surface tarnish, marginal staining and marginal fracture and the results were related to product, restoration age, restoration cavity class type, restoration size (normal or large Class II preparations) and tooth type (premolar or permanent molar). Dispersalloy (Johnson and Johnson, East Windsor, USA) gave restorations which were overall superior for the clinical characteristics examined. Large restorations on the occlusal surfaces of molar teeth showed more signs of deterioration over the study than did other restoration types. However, all restorations remained clinically satisfactory throughout the study.

Analysis of Variance↗
PubMed2006

The effect of preparation taper on the retention of cemented cast crowns under lateral fatigue loading.

STATEMENT OF PROBLEM: Clinicians have used resistance form as a basis for determining guidelines for preparation design to ensure clinical success of cemented cast restorations. Disagreement on whether clinical success follows the on-off or linear nature of resistance form continues. PURPOSE: The purpose of this study was to evaluate the number of cycles required to dislodge a cemented complete crown casting under a cyclic lateral load as a function of taper and to compare this relationship for the resistive and nonresistive ranges of taper. MATERIAL AND METHODS: Three dies were milled from stainless steel at each of the following tapers: 4, 8, 12, 16, 20, 24, 28, and 32 degrees. A gold-palladium metal-ceramic alloy crown was fabricated for each die, cemented, and subjected to lateral cyclic loading until failure or 1,000,000 cycles. The limiting taper for the dies with their given height and base was 26.6 degrees. Dies with taper less than 26.6 degrees had resistance form, whereas dies with taper larger than 26.6 degrees did not. A linear regression (alpha=.05) was used to evaluate the relation of cycles at dislodgement to taper. RESULTS: The average number of cycles to crown dislodgement or completion for each taper (SD), in units of 10,000, was as follows: 4 degrees, 100 (0); 8 degrees, 100 (0); 12 degrees, 93.54 (16.56); 16 degrees, 61.33 (38.47); 20 degrees, 25.73 (34.67); 24 degrees, 4.33 (7.36); 28 degrees, 0.06 (0.08); and 32 degrees, 0.05 (0.09). The crowns in the resistive area less than 26.6 degrees that demonstrated failure showed a linear regression with a correlation coefficient of -0.995 between the average number of cycles to dislodge the crown and the taper. The slope was significantly different from zero (P=.0048), with a value of -7.58 and a standard error of 0.53. CONCLUSION: The number of cycles required to cause crown dislodgement was linear after 12 degrees in the resistive area and nearly zero for preparations in the nonresistive area. The limiting taper concept closely predicted the transition point where the slope of the graph of cycles to dislodgement as a function of taper abruptly changed.

Cementation↗
PubMed2000

Design principles for cantilevered resin-bonded fixed partial dentures.

Recent clinical studies show 2-unit cantilevered resin-bonded fixed partial dentures to be as retentive or more retentive than their fixed-fixed counterparts. The fact that the 2-unit prosthesis is successful adds value to the clinical use of resin-bonded fixed partial dentures because the single-abutment prosthesis is even simpler and more cost effective than fixed-fixed designs. However, there is no evidence-based information relating to design principles for abutment preparation and framework design for the single-abutment, single-retainer prosthesis. The aim of this report is to suggest principles of design for the 2-unit cantilevered fixed partial denture, based on information gained from studies on fixed-fixed designs.

Cost-Benefit Analysis↗