This chapter is a natural continuation of the chapter on modeling. That chapter discussed techniques, while this one focuses on details, distinguishing features, customization, and finalization. In any study of shape, detail is everything. It adds value to an overall shape. A tiny detail can distinguish an object, making it unique and special. Without that detail, the object would not have the same expressive force or arouse the same emotion in the observer.
A posterior direct restoration cannot be executed without considering all the details that make the overall restoration esthetically pleasing and functionally effective. The need for detailing cannot be pinned down to a precise location on the occlusal surface. Detailing matters during construction of a ridge, a cusp, and the flow of a marginal ridge toward the occlusal surface. Each reconstruction area has its own volume and breadth; overlying increments must be proportional to the area and volume they restore, creating a harmonious balance.
The center of the occlusal surface is undoubtedly an area where many minor and significant details are concentrated. It represents the confluence of primary, secondary, buccal, and palatolingual ridges separated by grooves and fossae. All these features generate anatomical nooks and crannies that characterize the central anatomy, enhancing it with details that make the occlusal surface a natural work of art.
A detail that might seem irrelevant when considered by itself becomes contextualized as part of a natural sculpture when combined with other details, and the whole acquires new meaning. In the anatomical context of an occlusal surface, attention to detail makes hardly any difference to chewing efficiency but is crucial in esthetic terms. For example, the occlusal surface can be smooth and shiny or rough and irregular, resulting in a surface that shimmers with natural-looking highlights (see Fig 8-1a). Removing irregularities (see Fig 8-1b) means removing details that render a tooth unique. Removing grooves and wiping out the occlusal morphology (see Figs 8-1c and 8-1d) can reduce an appealing shape to an amorphous, monochrome, functionally inefficient surface. Run-of-the-mill shapeless fillings at best merely serve the purpose of filling a cavity and sealing the pulp-dentin complex.
Central gap sealing is the crucial stage of modeling when shape is defined. It is the stage when the gap is sealed and the central anatomy is enhanced. The in vitro example in Fig 8-2 uses colored composite to show how attention to detail can be managed in a very small space. This is demonstrated by the final orange increment, which seals and blends in with the previous blue increments. In this chapter, a qualitative leap will be made as a set of techniques are described for customizing and enhancing detail to make a restoration unique, referred to as detailing.
Making a Naturally Shaped Ridge
A ridge (Fig 8-3a) can be enhanced with anatomical details by following a few simple guidelines. A ridge can be made to look sinusoidal and dynamic with the aid of a small brush. A brush print on the distal side of the mesiobuccal ridge creates a depression and a kind of very light secondary groove (Figs 8-3b and 8-3c). When the brush head is applied again, the top of the mesiobuccal ridge is distorted from the mesial side in a distal direction (Fig 8-3d). The ridge tip moves distally, and the ridge crest acquires a sinusoidal configuration. When observing the newly modified ridge, it can be noted that the marks left by the brush have changed the mesiobuccal ridge and the features located mesially and distally to the ridge, ie, grooves and associated secondary ridges (Figs 8-3e to 8-3g).
This type of technique is also useful for making a ridge and/or groove look more sinusoidal and natural during a restoration involving the subtractive technique (Fig 8-4).
The first composite increments are designed to regulate the proportional relationship between the ridges to be reconstructed. The secondary grooves are sculpted by subtraction during the same stage. The tip of the sculpting instrument demarcates the groove, giving it depth and direction (Figs 8-5a and 8-5b). Sculpting a secondary groove changes the configuration of the primary ridge, making it more prominent so that it stands out within the overall morphology.
Unless a subtractive technique is used to sculpt grooves and fossae in a single mass of composite, grooves and fossae are constructed by building up increments (Figs 8-5c and 8-5d). A sinusoidal anatomical groove design is defined by building up increments while always keeping them gently separate from one another.
Making a Natural-Looking Groove
In mandibular second molars, the central portion of the occlusal surface can be sealed by making the mesiobuccal and distolingual ridges face one another. As first discussed in chapter 2, this gives rise to a very sinusoidal, protrusive groove with two triangular central fossae—one more buccal and distal, and the other more lingual and mesial. Working and nonworking grooves are positioned so that one faces more mesially and the other more distally in relation to the center of the tooth. All these asymmetries add up to a very natural and anatomical occlusal design. For large Class 1 cavities, the simultaneous modeling technique simplifies the distribution of ridge volumes as well as their orientation and extension. The occlusal surface can therefore be designed simply by means of five increments in three steps:
- The first (blue) increments define the mesiobuccal and distolingual ridges. They are adapted and modeled simultaneously (Fig 8-6a to 8-6c).
- The second (orange) increments define the mesiolingual and distobuccal ridges. They are adapted and modeled simultaneously (Figs 8-6d and 8-6e).
- The final (white) increment that prolongs the distolingual ridge is built up on the other ridges, sealing the central gap and defining the two triangular fossae (Figs 8-6f and 8-6g).
The maxillary premolar is constructed with two increments, one buccal and the other palatal. This results in two ridges with convex occlusal extensions facing one another (Figs 8-7a to 8-7d). Once the marginal ridges have been added (Figs 8-7e to 8-7i), the crucial stage of the restoration is sealing the mesiodistal groove. The increment forming the palatal ridge is pushed to the center of the occlusal surface and cured (Figs 8-7j to 8-7m). The buccal ridge increment is adapted to the newly created palatal ridge by alternating between the sculpting instrument, which subtracts composite or moves it away from the palatal ridge, and the brush, which tends to build up composite on the cured palatal ridge (Figs 8-7n to 8-7q).