Careful diagnosis and treatment planning will aid the clinician in identifying the etiology of enamel breakdown and carefully curating a minimally invasive plan that yields predictable long-term results. Using the principles routinely employed for indirect restorations for direct restorations will improve the confidence of the dentist and exceed patient expectations. Here is case report using a technique that combines the benefits of a direct composite layering approach with those of indirect veneers to achieve optimal shade matching, marginal adaptation, and natural morphology.
The treatment plan for this case is ultimately to restore the four maxillary incisor teeth using a conservative technique by fabricating direct-indirect composite veneers. These restorations will be fabricated in a single appointment. The benefits of this approach include an ultraconservative approach to restoring these teeth and an ideal enamel surface area for predictable bonding. In addition, should this case require repair, it is a simple task.
Orthodontics using clear aligners effectively set up the tooth positions for this case. The teeth were positioned for optimal restorative space, occlusion, and oral hygiene. Once orthodontics was completed, a direct-indirect composite resin mock-up was completed to test the proposed composite resin shades, incisal edge position, point angle position, and embrasures (figure 2). A silicone matrix was utilized to guide tooth preparation and composite resin layering.
The direct-indirect composite veneering technique is additive and indicated to restore teeth that require tooth preparation or via a prepless technique. Tooth preparation is required if the original tooth structure is overcontoured or discolored. Each veneer is fabricated one at a time, starting with a single central incisor. These veneers can be as thin as a contact lens or thicker as needed.
The endurance and durability of direct composite resin restorations are multifactorial, and the triad of material, technique, and the operator must be considered when evaluating failure causes [7]. On the other hand, these materials can produce outstanding and long-lasting results when correctly selected and handled [8]. In clinical investigations, minor discoloration has been linked to patient unhappiness with veneers. It has also been thought to be proof of a minor flaw, such as partial debonding or microleakage [9]. The importance of marginal leakage in the maintenance of dental esthetics cannot be overstated [2]. Because of the differences in physical qualities between teeth and restorative materials, gaps arise at the tooth/restoration interface, resulting in marginal microleakage, which is the leading cause of failure in dental esthetic composite restorations [10].
The direct-indirect veneer technique, also known as (semidirect) veneer technique, is a modified veneer application technology that combines the benefits of both direct and indirect veneer techniques [5, 11]. When this technique was first introduced, the main advantages emphasized the ability to expose intraorally made veneers and inlays to extraoral light and heat to optimize their physical and mechanical properties, clinical behavior, excellent esthetics, and unrivaled marginal adaptation and polishing [12].
Microfills were the most common composites used for veneering at first, owing to a desire to emulate the reflectivity of the enamel surface [13]. Microfill has been proved to be the only composite material that can withstand the test of time in terms of color stability and polishability [14]. On the other hand, nanohybrid composite is a popular direct veneer material because it incorporates nano- and microsized filler particles that provide good mechanical strength as well as finishing and polishing results and a relatively smooth surface and a high gloss that are similar to porcelain restorations [15] As a result, we used two types of composite resin in this study: microfilled and nanohybrid composite restorations and two veneer application techniques: direct veneer and direct-indirect veneer to assess the gingival marginal sealing ability of composite laminate veneers using the dye penetration method. To our knowledge, no research has been done to compare the marginal sealing performance and microleakage of direct veneer versus direct-indirect veneer techniques.
According to the composite application techniques, the teeth were randomly divided into two major groups: group A: direct veneer technique ( teeth) and group B: direct-indirect veneer technique ( teeth). The composite utilized was then used to separate each leading group into two subgroups ( teeth). Nanohybrid composite resin (Tetric N-Ceram, Ivoclar Vivadent, Liechtenstein) was utilized in subgroup 1 ), while microfilled composite resin (Renamel Microfill, Cosmedent, Chicago, IL) was used in subgroup 2 (). The division of the groups is depicted in Figure 2. For standardization, the A1 composite shade was chosen.
(1) Application of Composite Resins. The composites selected for each subgroup of this group were initially applied to the labial tooth surface (without acid etching or bonding) with a stainless steel Heidemann spatula, brush, and contouring instrument equipped with an Optrasculpt pad, using gentle digital pressure to create the primary contour of the restoration. In this method, we utilized a layering strategy without using a bonding agent, followed by a 20-second light cure, Fahl [5] and Fahl and Ritter [11] outlined the step-by-step procedure for direct-indirect veneer.
The score, percentage, and range for the microleakage in each of the groups and subgroups are shown in Table 1. The mean and standard deviation (SD) are shown in Table 2, indicating that the most negligible dye penetration was observed in group B when using the direct-indirect veneer technique with a nanohybrid composite resin material () (0.22%). In contrast, the most dye penetration was observed in group A when using the direct veneer technique with microfilled composite resin material () (31.63%).
The mean dye penetrations of nanohybrid and microfilled composites were compared when both veneering techniques were used; in group A, when the direct veneering technique was used, the microleakage of the nanohybrid composite was significantly less than that of microfilled composite, with the difference being statistically highly significant (). When the direct-indirect veneering technique was used in group B, the microleakage of the nanohybrid composite was also less than that of the microfilled composite, and the difference was statistically highly significant (), as demonstrated in Table 3.
The mean dye penetrations of direct veneer and direct-indirect veneer were also compared when both types of the composite were used; in subgroup 1, when nanohybrid composite was used, the microleakage in the direct-indirect veneer was less than that in the direct technique, and the difference was statistically significant (). Additionally, when a microfilled composite was used in subgroup 2, the microleakage in the direct-indirect veneer was smaller than that in the direct approach, and the difference was statistically significant () (Table 4).
Numerous factors influence the esthetic quality and endurance of dental restoration, including the technique used to install the restoration, the degree of polymerization of the composite, and the type of restorative material employed [20]. Thus, the purpose of this study was to determine the effect of the composite laminated veneer application technique (direct and direct-indirect veneer) as well as the effect of the composite resin type (nanohybrid and microfilled composite) on the gingival marginal microleakage of the composite laminated veneer interface.
Regardless of the composite type, the results of this study indicated that group B experienced less microleakage when using the direct-indirect veneer approach than group A when using the direct veneer technique. This is because the final strength of the tooth-restoration complex is significantly dependent on adhesive techniques when using the direct-indirect approach [28]. Additionally, this approach minimizes polymerization shrinkage since the polymerization happens outside the cavity, leaving only the resin cement to contract and connect the restoration to the tooth structure [29]. To clarify further, with the direct-indirect procedure, the restoration is sculpted directly into the tooth structure and removed following light activation; it can then be thermally treated, completed, and polished before adhesion and luting processing. The purpose of the extraoral light curing and heat tempering is to enhance monomer conversion while avoiding detrimental pulp overheating in essential teeth. As a result, the final restorations have superior mechanical qualities and unmatched marginal adaptation and polishing.
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