Comparison of saddle contoured metal matrix and pre-contoured self-adhesive matrix in composite resin class II restorations; an in vivo study.

OBJECTIVE: To evaluate composite class II restoration proximal contacts and contours by comparing saddlecontoured metal matrix and pre-contoured self-adhesive matrix system. METHODS: The randomised controlled trial (NCT05414656) was conducted at the Department of Operative Dentistry, School of Dentistry, Shaheed Zulfiqar Ali Bhutto Medical University, Pakistan Institute of Medical Sciences, Islamabad, Pakistan, from May to October 2022, and comprised of patients having supra-gingival class II cavities. They were randomised into class II restoration with saddle-contoured matrix band group A, and restoration with pre-contoured self-adhesive matrix group B. The tightness of proximal contacts was evaluated using the Fédération Dentaire Internationale criteria and the quality of proximal contours was assessed using clinical and radiographic examination. Data was analysed using SPSS 16. RESULTS: Of the 60 subjects, 42(70%) were females and 18(30%) were males. The overall mean age was 38.03±15.33 years. There were 30(50%) subjects in each of the 2 groups. The highest restoration was needed in the upper premolar 20(33.3%). The tightness of proximal contact was not significantly different between the groups (p=0.94). Clinical examination for production of good contours was higher in group A compared to group B, but the difference was not significant (p>0.05). CONCLUSIONS: There was no significant difference between saddle-contoured metal matrix and pre-contoured selfadhesive matrix for composite class II restoration proximal contacts and contours. Clinical Trial Link: https://clinicaltrials.gov RCT (NCT05414656).

Evaluation of the proximal contact tightness in class II resin composite restorations using different contact forming instruments: a 1-year randomized controlled clinical trial.

BACKGROUND: Proper proximal contact in direct composite restorations is crucial for periodontal health. Over a one-year period, this study was conducted to assess successive biological changes in proximal contact tightness PCT in class II direct composite restorations and the adjacent teeth by applying sectional matrix system along with different contact forming instruments. METHODS: 72 direct compound class II composite restorations were performed in patients aged 18-40 years and divided into 4 groups: Group I (n = 18): proximal contact was restored with Palodent plus sectional matrix system, Group II (n = 18): Trimax as contact forming instrument, Group III (n = 18): Perform as contact forming instrument and Group IV (n = 18): Contact pro as contact forming instrument. All contact forming instruments were used along with Palodent plus matrix system. PCT was measured using a digital force gauge before (T0), immediate post operative (T1) and at 3 (T2), 6 (T3), 9 (T4), and 12 months (T5) after restorative treatment. Using One-Way ANOVA, Tukey's post hoc test, and Bonferroni correction, PCT values were compared between groups before and after the intervention restoration. Meanwhile, for comparisons within groups, a paired t-test was conducted (p ≤ 0.05). RESULTS: Contact forming instruments combined with Palodent plus sectional matrix system achieved better PCT. Trimax led to a statistically considerable tighter proximal contacts than the other groups (p < 0.05). No statistically significant difference was found in PCT between Contact pro-2, Perform and Palodent plus sectional matrix system. By means of multivariate analysis, the PCT between both T0 and T1 were increased (p < 0.001) and then it decreased till T5. CONCLUSIONS: The use of transparent contact forming instruments achieved greater PCT compared to Palodent sectional matrix system alone that gradually decreased throughout 12 months and reached the PCT between the natural teeth. Using Trimax system provided the tightest proximal contacts. Additionally, digital force gauge was confirmed as an inclusive and accurate method to quantify PCT. TRIAL REGISTRATION: ClinicalTrials.gov NCT05749640: 24/5/2022.

Impact of matrix systems on proximal contact tightness and surface geometry in class II direct composite restoration in-vitro.

BACKGROUND: Poor contact tightness and contour in class II composite restorations are significant problems in clinical practice. They affect occlusal stability and periodontal health. The aim of this study was to evaluate proximal contact tightness and contour established after completing class II direct composite restorations using two pre-contoured matrix systems. METHODS: Standardized mesio-occlusal cavities were prepared in twenty typodont lower right first permanent molar teeth. Prepared teeth were randomly divided into two groups according to matrix system: Group 1, Sectional matrix system with a separation ring (Palodent V3); and Group 2, Circumferential matrix system with integrated tightener (Palodent 360). Contact tightness was evaluated using universal testing machine. Area, depth and curvature radius of proximal surface concavity in the restoration were evaluated using contact stylus profilometer. T-test was used for comparison between groups. RESULTS: Sectional matrix showed higher contact tightness than circumferential matrix system. The results of proximal surface concavity in the restoration showed significantly higher area and depth of concavity with lower radius of curvature in circumferential matrix compared to sectional matrix. CONCLUSIONS: The use of separation ring with sectional matrix provides superior contact tightness compared to circumferential matrix. However, both matrix systems presented some deficiency regarding proximal contour of direct class II resin composite restoration.

Comparison Between Two Types Of Matrix Systems For Contact Tightness In Class-Ii Composite Restorations.

BACKGROUND: The reconstruction of proximal defects with tight contacts has always been a challenge for dental clinicians, especially with composite material. Recent literature shows that the most frequently used matrix systems for the restoration of proximal cavities are circumferential or sectional matrix band systems. The objective of this study was to compare the contact tightness that is achieved with these two matrix band systems when using composite material. METHODS: A total of 30 patients, i.e., 60 cavities were selected in this quasi-experimental study. Patients with two cavities in the posterior teeth were selected. Both the cavities were restored with the circumferential system, i.e., Tofflemire and sectional matrix band system, i.e., Palodent plus on the same appointment. Hence both systems were used in every patient and then contact tightness assess was ed based on an evaluation criterion, i.e., Fédération Dentaire Internationale clinical criteria for evaluation of contact in direct and indirect restorations. To make a comparison between the two systems Chi square test was used and p<0.05. RESULTS: The mean age of the patients in the study was 31 years (SD, 7.59 years) with a range from 18 to 45 years. Most of the contact tightness in the Palodent matrix system was score 1 (n=33, 55%) and score 2 (n=17, 28.3%) while in Tofflemire was score 4 (n=28, 46.7%) and score 5 (n=19, 31.7%). Statistical analysis showed significance (p=.037) between Palodent matrix system contact tightness and Tofflemire. Conclusion: The sectional matrix band system was statistically superior to the circumferential matrix band system in achieving a tighter contact for class II composite restorations.

Sectional matrix solutions: the distorted truth.

Sectional matrix techniques offer more predictable solutions to achieving contact areas when placing direct interproximal posterior composites than circumferential matrix techniques, resulting in reduced reported complaints of food packing from patients. Despite this, a large majority of UK dentists and therapists don't currently use them. Sectional matrix systems are technique-sensitive to use, which can be a barrier to implementation for inexperienced users. The matrices can easily distort during their placement and stabilisation and when placing the restorative material. This can result in unwanted, clinically relevant problems in the resulting restorations, some of which may not be discernible once they have occurred. This paper explores the advantages and disadvantages of sectional matrices and the processes and techniques involved in their use, before discussing the potential for distortion at each step. It offers solutions to some of the commonly seen problems which will provide more predictable outcomes for those already using these techniques and encourage non-users to add them to their armamentarium.

2021 Trends in Restorative Dentistry: Composites, Curing Lights, and Matrix Bands.

Composite materials remain a mainstay as a restorative option in dentistry. This article reviews some of the most recent updates and projected future trends in dental composites, along with curing lights and matrix systems.

Effective Protocol for Daily High-quality Direct Posterior Composite Restorations. The Interdental Anatomy of the Class-2 Composite Restoration.

The importance of the interdental anatomy of a class-2 direct composite restoration is one of the most underestimated topics in direct posterior composite restorations. The proximal emergence profile of the restoration and the contact area should be designed to maximize arch continuity and to minimize food impaction. Other restorative criteria that must be fulfilled are marginal adaptation compatible with the dental and periodontal integrity, and geometry of the marginal ridge compatible with the mechanical integrity of the restoration under load. Shortcomings will result in masticatory discomfort, caries, periodontal problems and undesired movement of teeth. In vitro and in vivo studies showed that the use a contoured sectional metal matrix band with a separation clamp results in the tightest contact point. However, this matrix system also has shortcomings and does not give the expected result in all class-2 cavities. The variation in depth, width of the box, distance between the cervical cavity margin and the adjacent tooth requires customization of the interproximal space. In order to realize this, sectional matrix bands with several profiles of curvature, variation of wedges and separation clamps, and the use of teflon tape are required. In addition, dentists should follow a protocol allowing them to build a proximal composite surface that fulfills the required restorative criteria. Pre-wedging, space evaluation, interproximal clearance, correct selection, positioning and stabilization of the matrix band are important steps in this protocol.

Use of Transparent Tips for Obtaining Tight Proximal Contacts in Direct Class II Composite Resin Restorations.

This article describes the clinical technique of using the transparent plastic tips of the LM-Contact Former system for obtaining tight proximal contacts in direct Class II composite resin restorations using noncontoured circumferential matrix bands. With this technique, the composite resin is pressed with the tip, which adapts intimately to the walls of the proximal box. Moreover, the total working time is reduced by filling the cavity, which remains after removing the transparent tip, with a bulk-fill flowable resin-based composite.

Comparison of two different matrix band systems in restoring two surface cavities in posterior teeth done by senior undergraduate students at Qassim University, Saudi Arabia: A randomized controlled clinical trial.

CONTEXT: Dental students commonly face the problem of overhanging proximal margins and unsatisfactory proximal contact points (PCPs) while restoring Class II cavities in posterior teeth. Various matrix band systems are used in dental clinics to avoid such problems. AIMS: The aim of this study is to compare the effects of two matrix band systems, circumferential matrix system and sectional matrix system on the PCPs and contours when restoring Class II cavities in posterior teeth. SETTINGS AND DESIGN: This was a randomized controlled clinical trial done at College of Dentistry, Qassim University, Saudi Arabia. SUBJECTS AND METHODS: Total 1200 Class II cavities in teeth were selected for this study. Treatment was done by senior undergraduate students. Cavities were randomly divided into two groups. Group 1: Total 600 cavities were restored using circumferential band system. Group 2: Total 600 cavities were restored using sectional band system. Teeth were restored either with the composite or the amalgam restoration. Contact points were evaluated. The presence or absence of proximal overhangs was assessed. Overhanging margins were categorized as positive overhangs, negative overhangs, and absent overhangs. STATISTICAL ANALYSIS USED: To identify the relationship between matrix band systems and other factors, Chi-square tests (χ2-tests) and Z-tests were used. Pearson correlation coefficient was computed and logistic regression analysis was carried out to assess variables that can affect proximal margins and contact points of final restorations. RESULTS: All optimum contacts 389 (100%) were found in restorations done using sectional band system. A highly significant association was found between open contact points and negative overhanging margins with the use of circumferential matrix band system (P < 0.00). CONCLUSION: Sectional matrix band system has been found superior to circumferential matrix band system.

Retrofitting a foundation restoration to an existing ceramic crown after endodontic treatment: A dental technique.

This article describes the fabrication of a foundation restoration after endodontic treatment using a preexisting ceramic prosthesis and polytetrafluoroethylene (PTFE) tape as a barrier. This technique presents a solution if the prosthesis and marginal integrity are to be maintained.

Depth of cure of proximal composite resin restorations using a new perforated metal matrix.

The purpose of this study was to compare the depths of cure of a proximal box preparation filled in bulk with various approaches: filled with a bulk-fill or conventional composite; placed with a new perforated metal matrix, a traditional metal matrix, or a clear matrix; and polymerized with either occlusal-only or tri-sited light curing. After tri-sited curing, the use of the new perforated metal matrix band resulted in a depth of cure that was not significantly different from that achieved with the use of metal bands (removed during curing) or transparent matrix bands. Adequate polymerization was obtained at depths of more than 5.0 mm for the bulk-fill composite and more than 4.0 mm for the conventional composite when tri-sited light curing was used. Tri-sited light curing resulted in a significantly greater depth of cure than occlusal-only curing. The perforated metal band may be used as an alternative to the use of solid metal bands or transparent matrix bands to provide similar depths of cure for composite resins, with the possible benefits of malleability and the ability to leave the band in place during tri-sited light curing.

Restauraciones transicionales de resina mediante la técnica de matriz transparente / Transitional resin restorations with the transparent matrix technique

La colocación de restauraciones directas a base de resina en el área de premolares y molares permite realizar tratamientos complejos en pacientes afectados por atrición dental severa y/o bruxismo. Hoy en día gracias a la técnica de grabado ácido, la fuerza de adhesión de la resina al esmalte disminuye la microfi ltración y sensibilidad postoperatoria. El objetivo de este artículo es describir la rehabilitación provisional mediante restauraciones adhesivas de resina compuesta en un paciente con atrición dental severa, el cual recibirá posteriormente tratamiento de ortodoncia por discrepancia de las arcadas. Al término de este tratamiento se colocarán restauraciones onlay de disilicato de litio (AU)

The placement of resin-based direct restorations in the area of premolars and molars allows the treatment of complex cases in patients aff ected by dental attrition and/or bruxism. Nowadays, due to the acid etching technique, the bond strength of the resin to the enamel will reduce the micro-leakage and post-operative sensitivity. The aim of this article is to describe the provisional rehabilitation with resin adhesive restorations, in a patient with a severe dental attrition, which will receive orthodontic treatment due to discrepancies in the arches. At the end of this treatment, ceramic restorations will be placed (AU)

Use of a Modified Matrix Band Technique to Restore Subgingival Root Caries.

Given the increasing incidence of root caries in the elderly population, clinicians frequently must isolate and restore subgingival preparations. This article demonstrates a technique utilizing a modified Tofflemire matrix band that creates a preparation free of crevicular fluid and blood for restoration with resin-modified glass ionomer cement.

Evaluation of Bond Strength, Marginal Integrity, and Fracture Strength of Bulk- vs Incrementally-filled Restorations.

PURPOSE: This study evaluated the effect of application technique and preparation size on the fracture strength (FS), microtensile bond strength (µTBS) and marginal integrity (MI) of direct resin composite restorations. MATERIALS AND METHODS: Conservative (5 × 2 × 2 mm) or extended (5 × 4 × 2 mm) preparations below the cementoenamel junction were performed in 140 human maxillary premolars (n = 70 per group). After adhesive application (XP Bond), half of each group was restored with the bulk technique (one 4-mm increment of Surefill SDR Flow plus one 1-mm horizontal capping layer of TPH3 [Spectrum TPH3 resin composite]) and half incrementally (TPH3 in three horizontal incremental layers, 1.5 to 2 mm each), all using a metal matrix band. After storage (24 h at 37°C), the proximal surfaces of each tooth were polished with Sof-Lex disks. For FS measurement, 60 restorations were mounted in a universal testing machine and subjected to a compressive axial load applied parallel to the long axis of the tooth, running at a crosshead speed of 0.5 mm/min. For µTBS testing, 40 teeth were longitudinally sectioned to obtain resin-dentin bonded sticks from the cavity floor (bonded area: 0.8 mm2). Specimens were tested in tension at 0.5 mm/min. The external marginal integrity of both proximal surfaces was analyzed using SEM of epoxy resin replicas. The µTBS, marginal integrity, and fracture resistance data were subjected to two-way ANOVA, and Tukey's post-hoc test was used for pair-wise comparisons (a = 0.05). RESULTS: Fracture resistance, microtensile bond strength, and marginal integrity values were not statistically significantly affected by application technique or preparation size (p = 0.71, p = 0.82, and p = 0.77, respectively). CONCLUSIONS: The use of a bulk-fill flowable composite associated with a conventional resin composite as a final capping layer did not jeopardize the fracture strength, bond strength to dentin, or marginal integrity of posterior restorations.

Matrix description of the complete topology of three-dimensional cells.

A new, efficient method based on a series of matrices is introduced to completely describe the detailed topology of individual domains and their topology evolution in three-dimensional cellular structures. With this approach, we found a lot of new topological grain forms which are never reported before, i.e., there are total 8 and 32 topological forms for 7- and 8-faced grains respectively, other than the reported 7 and 27. This method is proved to be a practical tool to predict all possible grain forms efficiently. Moreover, a connectivity index of grain forms serves as a new convenient differentiator of different multicellular structures.

Depth and distribution of the cure in a resin-based composite cured in a simulated Class II cavity.

PURPOSE: To examine the effect that a stainless steel (SS) matrix band has on the depth and distribution of cure of a resin-based composite (RBC) in a simulated Class II cavity. METHODS: RBC was cured for 20 seconds in a simulated Class II cavity with and without a SS matrix band, and after 24 hours the specimens were scraped back and ground to expose a vertical central plane where Knoop micro-hardness (KHN) mapping was conducted from 0.05-1.5 mm from the band and in 0.5 mm intervals from the top of the specimens. The effect of different angles of the light guide on the distribution of hardness was also examined. RESULTS: KHN values near the SS matrix band were significantly lower (P < 0.05) than within the bulk of the specimen and were lower than those found without the matrix band. Angles of incidence for the curing light-guide produced changes in the distribution of KHN within the specimens, but particularly near the matrix band, and with a 35° angle of incidence, the depth of cure was significantly different from that of normal incidence of the light.

Análise da efetividade de polimerização, adaptação marginal e interna de restaurações Classe II de resinas compostas de inserção em bloco utilizando diferentes matrizes / Effectiveness of cure, marginal and internal adaptation of Class II bulkfill composites restorations made with different matrices bands

O objetivo deste estudo foi analisar a efetividade de polimerização, a adaptação marginal e interna de resinas compostas para dentes posteriores, empregando diferentes matrizes associadas ao envelhecimento artificial. Cento e vinte incisivos bovinos foram cortados e desgastados para simular dentes posteriores, nos quais foram realizados preparados de Classe II, com o ângulo cavo superficial gengival em dentina. As cavidades tinham 6 mm de altura (ocluso-cervical), 3 de largura(vestibulo-lingual) e 1,5 de profundidade (mesio-distal). Os espécimes foram divididos em seis grupos de acordo com o material restaurador utilizado: GrandioSO (Voco)– convencional incremental, G-aenial universal flo (GC)– fluída incremental, Xtrafil (Voco)– convencional com inserção em bloco, X-tra base (Voco)– fluída com inserção em bloco, Venus Bulk Fill (Kulzer)– fluída com inserção em bloco e SureFil SDR (Dentsply)– fluída com inserção em bloco. As resinas fluídas com inserção em bloco foram inseridas em incremento de 4 mm e receberam uma cobertura oclusal de 2 mm utilizando a resina GrandioSO, com exceção da X-tra fil que foi coberta com uma camada adicional do mesmo material. Nos demais grupos foi utilizada uma técnica incremental de 2 mm. Metade dos espécimes foi restaurada com matriz metálica e a outra metade com matriz de poliéster. O percentual de polimerização foi mensurado através da dureza Knoop e da relação dureza base/topo. A média da largura das fendas marginais presentes nas margens de cada restauração foi calculada após medição, em micrometros, no microscópio óptico (100x). Os espécimes foram submetidos à ciclagem mecânica (500,000 ciclos) e térmica (1,000 ciclos) e a fenda marginal foi avaliada novamente. Para fenda interna, os espécimes foram seccionados em uma cortadeira de precisão e o comprimento, em milímetros, da parede gengival que apresentava fenda foi mensurado no microscópio óptico. Foi calculada então a porcentagem de fenda em relação ao comprimento total ...

The aim of this study was to analyze the effectiveness of cure, marginal and internal adaptation of composite resins for posterior teeth using different matrices bands associated with artificial aging. One hundred and twenty bovine incisors were cut and flattened in order to simulate posterior teeth, and then were prepared for class II cavities with gingival cavosurface margin in dentin. Cavities had 6 mm height(occluso-cervical), 3 mm width (bucco-lingual) and 1.5 mm deep (mesio-distal).Specimens were divided into six groups according to the restorative material:GrandioSO (Voco)- conventional, G-aenial universal flo (GC)- flowable, X-tra fil (Voco)- conventional bulk, X-tra base (Voco)- flowable bulk, Venus Bulk Fill (Kulzer)- flowable bulk, and SureFil SDR (Dentsply)- flowable bulk. Bulk-fill composites were placed in single increment of 4mm and received a 2mm occlusal coverage of GrandioSO, with the exception of X-tra fil which was covered with a layer of the same material. The remmaing groups were restored in 2 mm incremental technique. Half ofthe specimens were restored with metallic and the other half with polyester matrix. of cure was measured by Knoop hardness and the bottom/tophardness ratio was evaluated. The average width of marginal gaps present in the restoration was calculated after optical microscope measuring (100x), in microns. The specimens were subjected to mechanical (500.000 cycles) and thermal cycling (1.000 cycles) and marginal gap was evaluated again. For internal adaptation, the specimens were sectioned and the gap length, in millimeters, present on the gingivalwall was measured in an optical microscope. The percentage of gap length in relation to the total length of the wall was also calculated. Data were analyzed with three andtwo-way ANOVA and Tukey´s test. Regarding effectiveness of cure, significant differences were observed for resin factor. Composites G-aenial universal flo (82.08%) and GrandioSO(84.62%) had the highest cure ...