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 1,045 records · Page 58Linked to original sources
PubMed1999

Hybridization effectiveness of a two-step versus a three-step smear layer removing adhesive system examined correlatively by TEM and AFM.

PURPOSE: The objectives of this study were (1) to compare the hybridization effectiveness of two adhesive systems that are applied in respectively three and two steps, and (2) to determine the best resin-dentin interface preparation technique for atomic force microscopy (AFM). MATERIALS AND METHODS: The resin-dentin interface produced by the three-step OptiBond Dual-Cure (Kerr) and its simplified two-step successor OptiBond Solo (Kerr) was ultramorphologically examined using transmission electron microscopy (TEM) and AFM. Four different methods were used to prepare interface specimens for AFM: (1) polishing to a 0.1-micron finish with a silicon oxide suspension, (2) polishing to a 0.05-micron finish with an aluminum oxide suspension, (3) argon-ion etching, and (4) sectioning with a diamond knife. RESULTS: Both TEM and AFM demonstrated that some collapse of the exposed collagen fibril network, due to gentle postconditioning air-drying of the dentin surface, may not have been totally recovered through hybridization by the two-step adhesive formulation as opposed to the three-step precursor. From the four interface preparation methods, only diamond-knife sectioning revealed sufficient ultramorphologic detail and high resolution that can capitalize on the high resolution offered by AFM. CONCLUSION: First, the findings suggest that simplifying the application procedure of adhesives by combining the primer and adhesive resin into a single application step may reduce hybridization effectiveness. Future research should confirm this effect for other two- versus three-step adhesive systems. Second, diamond-knife sectioning should be used for future topographic imaging and physicomechanical testing of resin-dentin interfaces by AFM.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Effects of different preparation techniques on the microleakage of compomer and resin fissure sealants.

PURPOSE: The aim of this study was to compare the microleakage of a compomer and resin sealant in vitro using different surface preparation techniques. METHODS: Microleakage of a compomer (Dyract Seal, DeTrey) and a resin sealant (Helioseal F, Vivadent) was investigated on 125 intact third molars. Materials and the surface preparation techniques were: Group 1--phosphoric acid (37%)+Helioseal F; Group 2--AlO2 air abrasion+Helioseal F; Group 3--nonrinse conditioner (NRC)+Prime&Bond+Dyract Seal; Group 4--phosphoric acid+Dyract Seal; Group 5--AlO2 air abrasion+Dyract Seal. RESULTS: Pretreatment with phosphoric acid produced the lowest microleakage scores when applied with compomer and resin fissure sealants and there was no statistical difference (P>.05). CONCLUSIONS: Compomer sealant used with a nonrinse conditioner (NRC) was not as successful as pretreatment with phosphoric acid etching, whereas AlO2 air abrasion pretreatment was ineffective in preventing microleakage in both sealants.

Acid Etching, Dental↗
PubMed2005

Complications associated with fractured file removal using an ultrasonic technique.

A technique utilizing modified Gates Glidden burs and ultrasonics has recently been advocated to remove fractured instruments from root canals. Varying extents of tooth structure are removed during this procedure, potentially leading to complications. This study evaluated the in vitro and in vivo complications associated with fractured file removal. Fractured instrument fragments were removed from three different levels (coronal, middle, or apical third) of mesiolingual canals of extracted human mandibular molars. The success rate, frequency of perforations, and root strength were recorded for each group. Perforations and unsuccessful file removal occurred only with fragments lodged in the apical third. Fracture resistance declined significantly with more apically located file fragments. A review of 60 clinical cases showed similar rates of successful file removal and rate of perforations. Removal of a fractured file fragment from the apical third of curved canals should not be routinely attempted.

Dental Instruments↗
PubMed2004

In vitro dentine permeability: the relative effect of a dentine bonding agent on crown preparations.

OBJECTIVE: The aim of this study was to determine whether a dentine bonding agent (DBA) had an effect in reducing fluid filtration under cemented provisional crowns. METHODS: Crown preparations on 34 premolars, randomly allocated to two equal-sized test and control groups, were assessed for dentine permeability by a fluid filtration technique. In the test group, prepared crowns were acid-etched and then treated with a DBA (Prime & Bond NT). In the control group, no such DBA was applied. Provisional crowns were cemented on both groups of teeth using non-eugenol zinc oxide cement. Fluid filtration rates were measured repeatedly after crown preparation, at cementation, 1 h, 1 day, 1 week and 3 weeks following crown cementation for both groups. Filtration rates were also measured after acid-etching and dentine bonding for the test group. RESULTS: There was insufficient evidence to suggest any statistically significant differences either between the two groups or, on average, across the five time points in each group in terms of the relative percentage of fluid filtration. CONCLUSION: The DBA used did not seal dentinal tubules any more than did the smear layer and provisional crowns luted with a non-eugenol ZnO cement.

Acid Etching, Dental↗
PubMed1999

Apical transportation revisited or 'where did the K-file go'?

CASE REPORT: This case report describes the outcome of a number of retreatments on a failed root filling in a maxillary first molar. The patient wanted all amalgams replaced by tooth-coloured Cerec restorations, including one in a symptomless maxillary molar. This tooth had a pulpotomy or a poorly done root-canal treatment 10 years earlier. The molar was root-canal retreated before placing the Cerec restoration and the palatal canal was filled 5 mm short of the radiographic apex. About 1 year later the patient presented with pain. Suspecting that a second mesiobuccal canal (MB-2) had not been located, a second non-surgical retreatment was instituted. MB-2 was not found and the palatal canal was retreated a third time, setting the working length 2 mm short of the radiographic apex. Because pain persisted palatally an apicectomy was performed and the tooth became symptomless. The resected palatal root apex was subsequently serially cross-sectioned, photographed and the canals analysed. Obvious apical transportation occurred during the cleaning and shaping procedures. Analyses of the canals showed that despite the retreatments, 11% of the canal cross-sectional area remained uncleaned although 7% of the root area was 'shaped'. Radiographically, the obturated palatal canal appeared reasonably well centred. However, this was disproved by the cross-sections, indicating that in this case, the clinician did not know where the K-Files had 'gone'. Apically, the obturated canal was certainly not within the natural canal. The pain located palatally was probably due to inadequate cleaning and shaping of the apical part of the root canal and its accessory canals.

Apicoectomy↗
PubMed2006

Reducing subjectivity in the evaluation of pre-clinical dental preparations for fixed prosthodontics using the Kavo PrepAssistant.

The evaluation of pre-clinical technical achievement in fixed prosthodontics cannot be objective when using visual examination of dental preparations. This is, however, still the main method used in dental schools. The present study introduces a new method, based on a mathematical formula, to reduce the problem. The idea emerged when using the Kavo PrepAssistant system (software version 1.05). This system is a 3D-scanner with software that can quantify geometrical differences between an instructor and student dental preparation in model teeth. Therefore, a mathematical formula was created, integrating selected clinically relevant geometric characteristics of dental preparations measured by the system. In this new formula, 70% of the evaluation parameters were computer analysed, whilst 30% were visually evaluated. This new method was compared with the traditional visual evaluation system during a pre-clinical practical examination, with the participation of 25 students. Using both methods to evaluate the 25 preparations, results showed similar grading for both methods (K-S test = 0.16; P < 0.05). Although this method does not provide overall clinical evaluation of student performance these results suggest that it can be helpful accessing technical achievement. In this method, the student has the guarantee that 70% of his/her grade results from an objective computer evaluation, with the possibility to visualise the mistakes with the software. It also reduces problems related to the calibration between different examiners. The Kavo PrepAssistant is a powerful tool in pre-clinical teaching, but has some drawbacks. It has to be developed towards the actual needs of pre-clinical departments, in order to achieve its full potential, as described in this study.

Computer-Aided Design↗
PubMed2002

Retention strengths of five luting cements on prefabricated dowels after root canal obturation with a zinc oxide/eugenol sealer: 1. Dowel space preparation/cementation at one week after obturation.

PURPOSE: This investigation examined the effect of 5 different cements on the retention strength of prefabricated endodontic dowels placed into root canals previously obturated with gutta percha and a zinc oxide/eugenol (ZOE) sealer. MATERIALS AND METHODS: Ninety-six single-rooted teeth were decoronated, filed, cleaned, sequentially shaped, and divided into 6 groups of 16 specimens each. Five of the groups were then obturated with gutta percha and a ZOE sealer. One group was not obturated and served as the control group. Dowel space preparation and dowel cementation for all groups were completed 1 week later. Ten-mm deep dowel spaces were prepared using size 6 Gates Glidden drills. Size 5 Paraposts were then cemented with 5 different cements: Panavia 21 for group 1 (unobturated controls) and group 2; Ketac-Cem glass ionomer for group 3; Fleck's zinc phosphate for group 4; Parapost (composite) Cement for group 5; and C&B Metabond 4-META for group 6. After 48 hours, the dowels were removed using a universal testing machine in tensile mode at 1 mm min(-1). RESULTS: The following results were found (all values in kg): group 1 (controls; Panavia 21) mean = 61.81, 95% CI = +/-8.65; group 2 (Panavia 21), mean=43.15, 95% CI = +/-7.81; group 3 (Ketac-Cem), mean =34.45, 95% CI = +/-4.93; group 4 (zinc phosphate), mean = 25.07, 95% CI = +/-5.03; group 5 (Parapost Cement), mean = 24.99, 95% CI = +/-5.35. None of the group 6 (C&B Metabond) specimens developed measurable bond strengths, so this group was excluded from parametric statistical analyses. An analysis of variance (ANOVA) showed a significant effect of group; pairwise multiple comparison procedures (Tukey test) showed that group 1 (controls) had significantly greater retention than all other groups (p <0.001); group 2 (Panavia 21) had significantly greater retention than groups 4 (zinc phosphate) and 5 (Parapost cement) (p <0.001). None of the other pairwise comparisons were statistically different. CONCLUSION: Paraposts cemented with Panavia 21 in unobturated root canals exhibited significantly higher retention than Paraposts luted with Panavia 21 and 4 different cements into dowel spaces prepared 1 week after obturation with gutta percha/ZOE sealer (p <0.001). Among the obturated groups, Panavia 21 cement (group 2) demonstrated significantly greater retention of Paraposts than zinc phosphate (group 4) and Parapost composite (group 5) cements (p <0.001). Ketac-Cem glass ionomer cement (group 3) had intermediate retention values that were not statistically different than those of groups 2, 4, and 5 (p >0.05). The 4-META cement, C&B Metabond, failed to polymerize.

Analysis of Variance↗
PubMed2005

Remaining dentin thickness in the apical 4 mm following four cleaning and shaping techniques.

The aim of this study was to determine the remaining dentin thickness (RDT) in the apical 4 mm following four cleaning and shaping techniques. Sixty human adult extracted mandibular incisors and 60 mesial buccal canals of mandibular molars were assigned to five groups of 12 teeth for each tooth type: Step-down stainless steel hand instrumentation, Lightspeed, Profile GT and 0.4 taper, K3 "g pack," control group. After instrumentation the teeth were sectioned at 0.5, 1.5, 2.5, and 3.5 mm short of working length (WL) and evaluated for the minimum RDT at each level. ANOVA of RDT showed significant differences among levels and techniques. For incisors, no technique yielded greater RDT than the other techniques (p < 0.0001). For molars, K3 had greater RDT than the other techniques (p = 0.0006) at the 1.5, 2.5, and 3.5 mm levels. While there were significant statistical differences in RDT among techniques at different levels, further study would be required to determine any significant clinical difference in RDT.

Adult↗
PubMed2005

Accuracy of electronic apex locators in comparison to actual length--an in vivo study.

OBJECTIVES: The measurement precision of four electronic apex locators (Root ZX, Morita, Tokyo, Japan; Endy, Loser, Leverkusen, Germany; Justy II, Hager-Werken, Duisburg, Germany; Endox Lysis, Milan, Italy) was examined in the present in vivo study. METHODS: The root canal length of 40 single-rooted and multi-rooted teeth was determined with the four devices prior to tooth extraction. To determine the actual root canal length, the apical third was longitudinally sectioned, the root canal instrument was positioned and the apex was examined using a microscope. RESULTS: The average measurement deviation (+/-SD) in relation to the apical constriction was 0.3 mm (+/-0.6) for the Root ZX, 0.7 mm (+/-1.0) for the Endy, 0.2 mm (+/-0.7) for the Justy II and 1.3 mm (+/-1.7) for the Endox. The limit of +/-0.5 mm from the apical constriction was attained by the Root ZX in 78%, by the Endy in 67%, by the Justy II in 80% and by Endox in 31% of all measurements. CONCLUSIONS: The latest generation of apex locaters provide the clinician with an accurate and useful adjunct for the determination of root canal length.

Dental Pulp Cavity↗
PubMed1999

Dental anxiety among patients prior to different dental treatments.

The purpose of the present study was to evaluate dental anxiety among patients anticipating various dental treatments. One hundred and eighty patients who were scheduled for specific dental treatments at the School of Dental Medicine, the Hebrew University--Hadassah, Jerusalem, Israel participated in the study. Patients were anticipating one of the following dental procedures: scaling, filling, root canal therapy, preparation for crown, periodontal surgery or extraction. For each of the six dental treatments, 30 patients were selected at random. Dental Anxiety Scale (DAS) questionnaires were completed by the patients while waiting for their treatments. The results indicated that extraction caused the highest score, followed by scaling (though not significantly). Patients in the 35 to 49 year age group showed the highest total DAS scores. Women demonstrated higher total DAS scores than men. The relative influence of gender, type of treatment and age on the anxiety scores is demonstrated by using logistic regression, which revealed gender to have the strongest impact on the DAS scores, followed by the type of treatment and age.

Adult↗
PubMed1998

The relationship between Universal Dental Anchorage System (UDA) pins and the dental pulp chamber, in vitro.

PURPOSE OF STUDY: The Universal Dental Anchorage (UDA) System incorporates the use of pins inserted into enamel and dentine to retain a pontic. The pins are placed horizontally into teeth in the region of the contact area and so are potentially placed close to the dental pulp. This study aims to investigate and measure this relationship to assess if the pulp may be placed at risk during pin hole preparation or UDA pin placement. METHODS: Teeth were assessed radiographically and pins placed according to manufacturer's instructions. The teeth were subsequently sectioned through the pin position and measurements from the pin tip to the pulp chamber made at 4X magnification. RESULTS: In the majority of the teeth the pins were in close proximity to the pulp chamber (mean +/- sd = 0.8 +/- 0.7 mm). Two pins were in direct communication with the pulp chamber. Seven pins were separated from the pulp chamber by only 0.1-0.5 mm and six pins by 0.6-1.0 mm. Three pins were more than 1.0 mm from the pulp chamber. CONCLUSION: The results suggest that the use of 2.1 mm UDA pins would, in many cases, represent a risk to pulpal health.

Adult↗
PubMedDate not supplied

Effects of preparation and luting system on all-ceramic computer-generated crowns.

PURPOSE: Computer-aided design/computer-integrated machining (CAD/CIM) allows defect-oriented custom-shaping of the inside surfaces of all-ceramic crowns. The purpose of this study was to examine the effect of inside crown form on fracture strength of cemented and bonded crowns. MATERIALS AND METHODS: Four preparation types were used: (1) "classic" with a butt shoulder of 1.2 mm, abutment height of 4 mm, and 6-degree convergence, (2) like type 1 with mesio-occlusodistal cavity, (3) like type 1 with height reduced by 50%, and (4) like type 1 with abutment reduced by 100% plus a pulp chamber cavity. Crowns were CAD designed on preparations 1 to 4 using identical outside morphology. Machined crowns were placed on abutments (a) without any media as controls (n = 15), (b) cemented (n = 15), and (c) bonded (n = 15), and were loaded until fracture. RESULTS: Zinc phosphate-cemented crowns (1b, 2b, 3b, and 4b) showed significant (P < 0.001) increase of fracture load values compared to uncemented control crowns (1a, 2a, 3a, 4a). Fracture load values of bonded crowns (1c, 2c, 3c) were significantly (P < 0.001) higher than those for cemented crowns. Bonded crowns with thick occlusal dimensions (3c and 4c) showed the highest fracture load values. CONCLUSION: Bonded all-ceramic CAD/CIM crowns with defect-oriented inside morphology and increased occlusal dimensions showed high fracture load values.

Analysis of Variance↗
PubMed2002

Crowns and other extra-coronal restorations: try-in and cementation of crowns.

Having successfully negotiated the planning, preparation, impression and prescription of your crown, the cementation stage represents the culmination of all your efforts. This stage is not difficult, but a successful outcome needs as much care as the preceding stages. Once a restoration is cemented there is no scope for modification or repeat You have to get it right first time. Decemented crowns often have thick layers of residual cement suggesting problems with either initial seating or cement handling. When the fate of restorations costing hundreds of pounds depends on correct proportioning of cements and the quality of the mix, the value of a well-trained and experienced dental nurse is easy to see. Both dentist and nurse need a working knowledge of the materials they are handling.

Cementation↗
PubMed2001

The microscopic diagnosis and treatment of a mandibular second premolar with four canals.

AIM: The purpose of this article is to report the case of a mandibular second premolar with four distinct canals. SUMMARY: It is generally recognized that incomplete instrumentation and cleaning of root canals will lead to failure in root-treated teeth. Before root canal treatment is performed, the clinician should be aware of the configuration of the pulp space of the tooth that is to be treated. Frequently, root canals are left untreated because the clinician fails to identify their presence, particularly in teeth that have anatomical variations or additional root canals. Traditionally, additional canals have been detected by clinical examination of the floor of the pulp chamber, and sometimes found radiographically. More recently microscopic examination of the pulp chamber using endodontic microscopy has assisted the identification of extra canals. A case report is presented that deals with the successful treatment of a mandibular second premolar with four canals. KEY LEARNING POINTS: Even in teeth with a low frequency of abnormal root canal anatomy, the possibility of additional root canals has to be considered in the clinical and radiographic examination of the patient. The ability to recognize and locate unsuspected canals is enhanced by microscopic investigation of the pulp chamber.

Adult↗
PubMed2003

Anesthetic efficacy of the supplemental X-tip intraosseous injection in patients with irreversible pulpitis.

The purpose of this study was to determine the anesthetic efficacy of the supplemental intraosseous injection, using the X-tip system in an apical location, in mandibular posterior teeth diagnosed with irreversible pulpitis when the conventional inferior alveolar nerve block failed. Thirty-three emergency patients, diagnosed with irreversible pulpitis of a mandibular posterior tooth, received an inferior alveolar nerve block and had moderate-to-severe pain on endodontic access. The X-tip system was used to administer 1.8 ml of 2% lidocaine with 1:100,000 epinephrine. The X-tip injection site was 3- to 7-mm apical to the mucogingival junction of the affected tooth. Success of the X-tip intraosseous injection was defined as none or mild pain on endodontic access or initial instrumentation. The results of this study demonstrated that 6 of 33 (18%) X-tip injections resulted in backflow of anesthetic solution into the oral cavity; none were successful in obtaining anesthesia. Twenty-seven of the remaining 33 X-tip injections (82%) were successful. We conclude that when the inferior alveolar nerve block fails to provide profound pulpal anesthesia, the X-tip system, when used in an apical location and when there was no backflow of the anesthetic solution into the oral cavity, was successful in achieving pulpal anesthesia in mandibular posterior teeth of patients presenting with irreversible pulpitis.

Adult↗
PubMedDate not supplied

Re-attachment of anterior fractured teeth: fracture strength using different techniques.

Fracture of anterior teeth by trauma is a common problem in children and teenagers. Complex metal-ceramic crowns with considerable loss of remaining sound structure are no longer necessary due to adhesive techniques, such as composite restorations and re-attachment techniques. This study compared the fracture strength of sound and restored anterior teeth using a resin composite and four re-attachment techniques. A "one bottle" adhesive system (One-Step, BISCO) and a dual cure resin cement (Duo-Link, BISCO) were applied. Thirty-five sound permanent lower central incisors were fractured by an axial load applied to the buccal area and randomly divided into five groups. The teeth were restored as follows: 1) bonded only = just bonding the fragment; 2) chamfer-group = after bonding, a chamfer was prepared on the enamel at the bonding line and filled with composite; 3) overcontour group = after bonding, a thin composite overcontour was applied on the buccal surface around the fracture line; 4) internal dentinal groove = before bonding, an internal groove was made and filled with a resin composite; 5) resin composite group = after a bevel preparation on the enamel edge, the adhesive system was applied and the fractured part of the teeth rebuilt by resin composite. Restored teeth were subjected to the same loading in the same buccal area. Fracture strength after restorative procedure was expressed as a percentage of the original fracture strength and the results analyzed by Kruskal-Wallis statistical analysis. The mean percentages of fracture strength were: Group 1: 37.09%, Group 2: 60.62%, Group 3: 97.2%, Group 4: 90.54% and Group 5: 95.8%. It was concluded that the re-attachment techniques used in Groups 3 and 4, as well as the composite restored group (Group 5), were statistically similar and reached the highest fracture resistance, similar to the fracture resistance of sound teeth.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2005

The effect of box preparation on the strength of glass fiber-reinforced composite inlay-retained fixed partial dentures.

STATEMENT OF PROBLEM: Nonstandardized box dimensions for inlay-retained fixed partial dentures (FPDs) may result in uneven distribution of the forces on the connector region of such restorations. PURPOSE: The objective of this in vitro study was to evaluate the effect of box dimensions on the initial and final failure strength of inlay-retained fiber-reinforced composite (FRC) FPDs. MATERIAL AND METHODS: Twenty-one inlay-retained FPDs were prepared using FRC (everStick) frameworks with unidirectional fiber reinforcement between mandibular first premolars and first molars. Boxes were prepared using conventional inlay burs (Cerinlay), and small and large ultrasonic tips (SONICSYS approx). Box dimensions were measured after preparation with a digital micrometer. All restorations were subjected to thermal cycling (6000 cycles, 5 degrees C-55 degrees C). Fracture testing was performed in a universal testing machine (1 mm/min). Acoustic emission signals were monitored during loading of the specimens. Initial and final fracture strength values (2-way ANOVA, Bonferroni post hoc tests, alpha =.05) and failure types (Fisher exact test) were statistically compared for each group. RESULTS: Significant differences (P =.0146 and P =.0086) were observed between the groups in the dimensions of the boxes prepared using conventional burs buccolingually (2.8-3.0 mm in molars, 3.1-4.3 mm in premolars) and the small size (2.5-2.9, 2.9-3.8 mm) or large size (2.6-3.8, 3.2-4.9 mm) ultrasonic tips for the premolars and the molars, respectively. No significant differences were found at the initial and final failures between the conventionally prepared group (842 +/- 267 N, 1161 +/- 428 N) and those prepared with either small (1088 +/- 381 N, 1320 +/- 380 N) or large ultrasonic tips (1070 +/- 280 N, 1557 +/- 321 N), respectively. The failure analysis demonstrated no significant difference in failure types but predominant delamination of the veneering resin (85%) in all experimental groups. According to acoustic emission tests, a higher energy level was required for final failure of the FRC FPDs with boxes finished using small ultrasonic tips. CONCLUSION: Standardized box dimensions showed no significant effect on fracture strength at either initial or final failure of the fiber-reinforced FPDs. The FRC FPDs with boxes refined with small ultrasonic burs required a greater energy level before failure. The type of failure observed after the fracture tests was primarily delamination of the veneering resin.

Acoustics↗
PubMed2006

C-shaped root canal in a maxillary first molar: a case report.

AIM: This case report presents an unusual C-shaped root canal system in a maxillary first molar tooth. SUMMARY: Although C-shaped root canals are most frequently seen in the mandibular second molar, they may also appear in maxillary molars. A literature search revealed only a few case reports of C-shaped root canal systems in maxillary molars. The present case describes a C-shaped canal in the buccal root of a maxillary first molar. The endodontic access cavity displayed two canal orifices, one leading to the canal system in the buccal root, the other into the palatal root canal system. In the buccal root, what appeared to be the mesial and distal canals joined to form a single C-shaped canal. KEY LEARNING POINTS: --Careful examination of radiographs and the internal anatomy of teeth is essential.-- The location and morphology of root canals should be identified at high magnification under the microscope.

Adult↗