In vivo Evaluation of Proximal Resin Composite Restorations performed using Three Different Matrix Systems.

OBJECTIVE: The aim of this in vivo study was to radiographically evaluate the proximal contour of composite resin restorations performed using different matrix systems. MATERIALS AND METHODS: Patients with premolars needing class II type resin composite restorations involving the marginal ridge were selected. Thirty premolars were selected and randomly divided into three groups (n = 10 each) to receive restorations using different matrix systems: group 1: metal matrix coupled to a carrier matrix and wood wedge (G1-MMW); group 2: sectioned and precontoured metal matrix and elastic wedge (G2-SME); and group 3: a polyester strip and reflective wedge (G3-PMR). After the restorative procedure, bitewing radiographs were performed and analyzed by three calibrated professionals. The quality of the proximal contact and marginal adaptation of the proximal surfaces was classified as either correct or incorrect (undercontour/overcontour). RESULTS: The Pearson Chi-square statistical test (α = 5%) revealed a statistically difference between frequencies of correct and incorrect restorations (α(2) = 6.787, p < 0.05). The group G2 SME produced a higher frequency of correct proximal contours (90%), while G1-MMW and G3-PMR had a ratio of 40% correct and 60% incorrect contours respectively. CONCLUSION: None of the matrix systems was able to prevent the formation of incorrect proximal contours; however, the sectioned and precontoured metal matrix/elastic wedge configuration provided better results as compared to the other groups.

Class II composite restorations and proximal concavities: clinical implications and management.

Clinical experience supports the notion that the restoration of MOD cavities may pose a challenge to the practitioner. Proper placement of precontoured matrices and commercial wedges help the clinician to establish an optimal emergence profile and sufficient contours. However, the presence of proximal concavities in premolars or molars can turn the reproduction of previous cervical architecture into an even more demanding task. Wedges with customized form or adequate design can precisely conform the matrix to the cavosurface area and prevent any gap formation. This article presents two different options that allow for successful and predictable reestablishing of anatomically correct contours and optimal proximal contacts in posterior teeth with proximal concavities.

The influence of matrix type on the proximal contact in Class II resin composite restorations.

PURPOSE: This in vitro study evaluated the efficiency of various types of matrices in reconstructing the proximal contact area in Class II resin composite restorations. MATERIALS AND METHODS: Standardized MO cavities were prepared on artificial molars of a manikin model. Resin composite (Spectrum TPH-3) restorations were placed using the following matrices (n=10): a) circumferential straight metal matrix with Tofflemire retainer-A, b) circumferential pre-contoured metal matrix system-B (Adapt SuperCap), c) circumferential pre-contoured transparent matrix system-C (Adapt SuperCap) and d) sectional pre-contoured metal matrix system-D (Palodent). After completion of each restoration, the manikin model was fixed on a tension-meter apparatus and an orthodontic wire was used to assess the contact tightness (CT), length of contact arc (LCA) and position of contact point relative to LCA% (PCP). The same measurements were performed on a group of intact molars (REF). The results were statistically analyzed with one-way ANOVA and the Tukey test, as well as the unpaired t-test (alpha=0.05). RESULTS: Matrix D provided the highest CT with the highest LCA, which presented a statistical difference relative to the intact tooth. Restorations with matrix B provided higher LCA than those with matrices A and C, which were found to be comparable to that of an intact tooth. The contact points (PCP) of the filled teeth were located more cervically in matrix D relative to the intact tooth (lower PCP), whereas matrices A, B and C showed more occlusal location (higher PCP). CONCLUSIONS: Differences were noted among all the matrices evaluated and none was proven sufficient to reconstruct the proximal contact characteristics of an intact tooth.

Class II composite restorations with metallic and translucent matrices: 2-year follow-up findings.

OBJECTIVE: The aim of this randomized, clinical study was to evaluate the performance of composite restorations placed with two matrix and wedge systems after a 2-year follow-up. METHODS: Twenty-three patients were selected, and received at least two Class II restorations, one with metallic matrix and wooden wedge and other with polyester matrix and reflective wedge. One dentist placed all the 109 restorations. All cavities were restored using Single Bond and P-60 (3M ESPE), according to manufacturer's instructions. In the metal matrix group, polymerization was performed from occlusal, and in the polyester group, through the reflective wedge. Restorations were evaluated at baseline and after 12 and 24 months by the modified USPHS criteria, and data were analyzed with Mann-Whitney and Wilcoxon Signed Rank tests (alpha=0.05). RESULTS: Fifteen subjects and 78 restorations were re-evaluated after 24 months. A significant decrease in the quality of cervical adaptation and proximal contacts by radiographic evaluation was evidenced (p<0.05), but no differences between the two matrix systems were detected (p>0.05). In the clinical evaluation there were no significant differences between matrices after 2 years (p>0.05). A compromising of marginal adaptation, marginal staining and proximal contacts aspects for both matrix systems was evidenced, and restorations placed with translucent matrices showed loss of color stability (p<0.05). CONCLUSIONS: Whereas restorations presented some clinical aspects somewhat compromised after 2 years, the matrix and wedge systems evaluated showed similar clinical performance.

In vivo and in vitro evaluation of Class II composite resin restorations with different matrix systems.

PURPOSE: To investigate in vivo and in vitro Class II composite restorations performed with two matrix and wedge systems. MATERIALS AND METHODS: One hundred nine Class II restorations were performed in 23 patients, 59 with metallic matrices and wooden wedges (group 1) and 50 with polyester matrices and reflective wedges (group 2). All cavities were restored using Single Bond and P-60 (3M ESPE). In the metal matrix group, polymerization was performed from the occlusal, and in the polyester group through the reflective wedge. To assess microleakage, 40 proximal standard slot cavities were prepared in 20 noncarious human third molars. In the mesial cavity, the gingival margin was located at the enamel level, and in the distal cavity at the cementum/dentin. Specimens were randomly divided into two groups (n = 20) and restored with Single Bond, Z-250 (3M ESPE), and the same techniques used in the in vivo study: metal matrix/wooden wedge (group 1) and polyester matrix/reflective wedge (group 2). Specimens were thermocycled (500 times, 5 degrees C to 55 degrees C), then isolated with nail varnish and immersed in fuchsin for 8 h. Specimens were sectioned longitudinally and microleakage was assessed under magnification (40X) using a standard scoring system. RESULTS: Data were subjected to the chi-square test, Mann-Whitney U-test, and Kruskal-Wallis H-test. Matrix systems presented similar results in the clinical evaluation and the in vitro microleakage test of Class II composite restorations. Dye leakage was minimal at enamel margins, and statistically lower (p < 0.05) than at cementum/dentin margins. CONCLUSION: The different matrix systems had no influence on clinical performance or in vitro sealing ability of Class II composite restorations.

Influence of curing methods and matrix type on the marginal seal of class II resin-based composite restorations in vitro.

This study determined the influence of light curing protocols and matrix type on the margin quality and marginal seal of Class II resin-based composite restorations. In extracted human molars, box-shaped MOD cavities with 1 mm wide interproximal bevels were prepared with cervical margins located at least 1 mm coronal to the cemento-enamel junction. The prepared teeth were mounted in a jig featuring artificial training teeth that served as adjacent teeth. A contoured sectional metal matrix band was placed in one interproximal area, and a section of a contoured transparent matrix band was placed in the opposite interproximal area. Both were kept in position using wooden wedges. After etching (35% H3PO4 gel) and the application of a three-step etch & rinse dentin adhesive (Optibond FL, Kerr), a thin layer of flowable resin-based composite (Revolution, Kerr) was applied to the interproximal margins. The cavities were restored by placing one horizontal and two oblique increments of a fine hybrid resin-based composite (Herculite XRV, Kerr). The curing protocols included one standard halogen protocol (Elipar Trilight, 3M ESPE, 40 seconds @ 800 mW/cm2), 3 halogen soft-start protocols (Step: Elipar HiLight, 3M ESPE; 10 seconds @ 150 mW/cm2, 30 seconds @ 850 mW/cm2; Ramp: Elipar TriLight, 3M ESPE, 5 seconds @ 100 mW/cm2, exponential increase for 10 seconds, 25 seconds @ 800 mW/cm2; Pulse delay: VIP Light, BISCO, cervical increment: 10 seconds @ 500 mW/cm2, occlusal increments: 3 seconds @ 200 mW/cm2, final irradiation after a 5 minute interval: 30 seconds @ mW/cm2) and 2 plasma arc high intensity protocols (PAC: Lightning Cure, ADT, 10 seconds @ 1400 mW/cm2; APO: Apollo 95E, DMDS, 2 x 3 seconds @ 1570 mW/cm2). The restored teeth were stored in 0.9% saline at 37 degrees C for 4 weeks and submitted to thermal cycling [TC] with 2500 cycles between 5 degrees C and 55 degrees C after 2 weeks. The margin quality before and after TC was analyzed in SEM using the replica technique, and the marginal seal was determined using the dye penetration test (50% AgNO3, 2 hours) at the end of the study. The matrix type did not significantly influence the quality and seal of the respective margins. For the complete restoration margin, one of the high intensity protocols (APO) produced a higher percentage of "continuous margin" compared to pulse delay irradiation after TC and lower percentages of "marginal opening" compared to halogen standard irradiation before and after TC. Halogen step irradiation produced a superior marginal seal compared to pulse delay curing at the occlusal margins; equivalent results were observed for all curing modes at the cervical margins. Neither a general advantage of soft-start irradiation nor a general disadvantage of high intensity curing was confirmed.

A survey of the use of matrix bands and their decontamination in general dental practice.

AIMS: The aims of this study were to determine the pattern of use and re-use of matrix bands in general practice in Scotland, to demonstrate which type of matrix band is most commonly used and to examine infection control measures of relevance to the safe use and re-use of matrix bands. SUBJECTS: 621 of Scotland's 1,849 general dental practitioners were randomly selected. DATA COLLECTION: A 19-item self-reported questionnaire was mailed in June 1999 with a follow-up mailing sent in August 1999. ANALYSIS: Data analysis involved descriptive statistics and cross-tabulation. Where appropriate, differences between categories were tested for significance by a Chi-square test. RESULTS: A total of 479 questionnaires were returned, representing a response rate of 77%. Reported compliance with routine glove wearing was high (91%). Most dentists (92%) provided training on instrument cleaning and sterilisation for their dental nurses. Ultrasonic baths were used by 59% of practitioners; the remainder soaked or manually scrubbed instruments to remove debris before autoclaving. The Siqveland matrix was the matrix of choice for 96% of respondents. 7% provided a new matrix band for each patient. Most (64%) changed bands only when they were bent or damaged; 29% changed them daily or weekly. Deterrents to use of a new band for each patient were cost (39%) and time (52%). A total of 54% of respondents considered matrix band replacement unnecessary between patients. CONCLUSIONS: The Siqveland matrix band is the most popular among the study group of dental practitioners. Re-use of matrix bands is common. Guidelines for the safe re-use of matrix bands are required.

Geriatric problem solving with adhesive dentistry, using the Contour Strip and direct composite placement.

The ability to create periodontally sound gingival and non-staining or plaque retaining interproximal margins on spacious carious lesions is a daunting challenge in many situations. The case as presented will illustrate the use of a unique matrix system, The Contour Strip from Vivadent, which will encompass the entire outline margins of the upper right lateral incisor of an elderly patient. The age of the patient has no bearing on the use of the technique, but merely reenforces the value of the system in all other situations mimicking a similar restorative obstacle. The use of this custom shaped matrix band, eliminate the free-hand placement and then the laborious creation and finishing of the restoration. LEARNING OBJECTIVES: After reading this paper the reader will understand the manipulation and use of a new labial matrix band which can totally surround the gingival and proximal margins of any anterior and pre-molar teeth. TECHNIQUE CONSIDERATIONS: There are four rules to follow when using adhesive dentistry: Proper preparation of tooth surfaces, both dentin and enamel through mechanical and/or chemical means. Creation of matrix formed molds. Injecting all resins, from the lowest to the highest viscosity. Polymerizing thoroughly through trans-enamel polymerization thus controlling shrinkage.

Creating tight, anatomically correct interproximal contacts.

Achievement of an excellent contact, one that provides a natural look and feel, reproducing the natural tooth contact or sometimes improving it, can be achieved in many ways. Understanding the separate issues of tightness and anatomy is crucial to achieving the desired result. In most cases, use of a contoured sectional matrix and McKean-style ring is the surest way to achieve the desired result. Unusual circumstances, such as wide preparations and malpositioned teeth, call for innovative techniques, some of which are illustrated in this article.