Figure 1. Stylization of the occlusion maps using the Y technique for posterior teeth. Left: The three key elements used to construct the posterior teeth. The occlusion maps are inserted into the occlusal tables (gray areas), which in turn have their boundaries established by the cusp tips (white spheres) surrounded more externally by the external tooth silhouette or contour. Right: A stylized drawing of the occlusion maps of the posterior teeth using the Y technique.

Figure 1. Stylization of the occlusion maps using the Y technique for posterior teeth. Left: The three key elements used to construct the posterior teeth. The occlusion maps are inserted into the occlusal tables (gray areas), which in turn have their boundaries established by the cusp tips (white spheres) surrounded more externally by the external tooth silhouette or contour. Right: A stylized drawing of the occlusion maps of the posterior teeth using the Y technique.

Figure 2. Four occlusal levels that must be considered when preparing posterior restorations: cusp tips, marginal ridges, main sulcus, and pits and fossae. Failure to respect this height relationship of the anatomical structures may necessitate extensive occlusal adjustment at the end of the restoration.

Figure 2. Four occlusal levels that must be considered when preparing posterior restorations: cusp tips, marginal ridges, main sulcus, and pits and fossae. Failure to respect this height relationship of the anatomical structures may necessitate extensive occlusal adjustment at the end of the restoration.

Figure 3. Different restorative techniques using conventional resin composites based on the number of shades used (represented by dark green, orange, and red colors): monochromatic (a), bichromatic (b), and polychromatic (c).

Figure 3. Different restorative techniques using conventional resin composites based on the number of shades used (represented by dark green, orange, and red colors): monochromatic (a), bichromatic (b), and polychromatic (c).

Figure 4. Initial aspect of an amalgam restoration to be replaced (a). Selective enamel etching with phosphoric acid (b). Application of self-etch adhesive system (c). A thin layer of opacifier is applied on darkened dentin (d). Insertion of dentin composite and design of occlusal map (e). Ochre, brown, and white tints applied to increase three-dimensionality (f). Enamel composite inserted using a single increment (g). Immediate final aspect of the restoration after removal of rubber dam and occlusal adjustment (h).

Figure 4. Initial aspect of an amalgam restoration to be replaced (a). Selective enamel etching with phosphoric acid (b). Application of self-etch adhesive system (c). A thin layer of opacifier is applied on darkened dentin (d). Insertion of dentin composite and design of occlusal map (e). Ochre, brown, and white tints applied to increase three-dimensionality (f). Enamel composite inserted using a single increment (g). Immediate final aspect of the restoration after removal of rubber dam and occlusal adjustment (h).

Figure 5. Restorative technique using single increment for dentin reconstruction. The cavity (a) is filled by single increment insertion of the dentin composite without photoactivation (b). The occlusion map is started using a very fine instrument (c). The instrument’s tip touches the bottom of the cavity, which allows the increments to be separated (d,e) and speeds up dentin construction.

Figure 5. Restorative technique using single increment for dentin reconstruction. The cavity (a) is filled by single increment insertion of the dentin composite without photoactivation (b). The occlusion map is started using a very fine instrument (c). The instrument’s tip touches the bottom of the cavity, which allows the increments to be separated (d,e) and speeds up dentin construction.

Figure 6. Class II restoration with composite. Positioning of partial matrices and wedges before application of adhesive system (a). Composite is placed in the proximal area and pre-polished with a brush before photoactivation (b). Aspect of the cavity with both proximal walls built with enamel composite (c). Proximal box filled with flowable bulk-fill composite (d). Restoration of artificial dentin and occlusal map design (e). Insertion of enamel composite on the occlusal surface (f). Aspect of the final occlusal anatomy (g) and finishing of proximal surfaces with scalpel blade (h).

Figure 6. Class II restoration with composite. Positioning of partial matrices and wedges before application of adhesive system (a). Composite is placed in the proximal area and pre-polished with a brush before photoactivation (b). Aspect of the cavity with both proximal walls built with enamel composite (c). Proximal box filled with flowable bulk-fill composite (d). Restoration of artificial dentin and occlusal map design (e). Insertion of enamel composite on the occlusal surface (f). Aspect of the final occlusal anatomy (g) and finishing of proximal surfaces with scalpel blade (h).

Figure 7. Different restorative strategies using bulk-fill resin composites. Green = flowable bulk-fill composite; Pink = conventional composite; Purple = regular bulk-fill composite. Reconstruction of the dentin portion with flowable bulk-fill composite and a conventional composite as the last layer (a). Reconstruction of the dentin portion with flowable bulk-fill composite and regular bulk-fill composite as the last layer for deeper cavities (b). Cavities that respect the limit of the composite polymerization depth can be restored with a single increment of regular bulk-fill composite (c). Deeper cavities can be restored with two increments of regular bulk-fill composite (d). Class II cavities can be restored with conventional composite emulating the enamel and its interior filled with flowable bulk-fill composite for dentin reconstruction. Similar to example (e), a regular bulk-fill composite can be used for the enamel (f). It is also possible to use flowable bulk-fill composite as a liner on the gingival wall for all techniques described here. Two increments of a larger volume of regular bulk-fill composite added above a liner with flowable bulk-fill composite (g).

Figure 7. Different restorative strategies using bulk-fill resin composites. Green = flowable bulk-fill composite; Pink = conventional composite; Purple = regular bulk-fill composite. Reconstruction of the dentin portion with flowable bulk-fill composite and a conventional composite as the last layer (a). Reconstruction of the dentin portion with flowable bulk-fill composite and regular bulk-fill composite as the last layer for deeper cavities (b). Cavities that respect the limit of the composite polymerization depth can be restored with a single increment of regular bulk-fill composite (c). Deeper cavities can be restored with two increments of regular bulk-fill composite (d). Class II cavities can be restored with conventional composite emulating the enamel and its interior filled with flowable bulk-fill composite for dentin reconstruction. Similar to example (e), a regular bulk-fill composite can be used for the enamel (f). It is also possible to use flowable bulk-fill composite as a liner on the gingival wall for all techniques described here. Two increments of a larger volume of regular bulk-fill composite added above a liner with flowable bulk-fill composite (g).

Figure 8. Examples of ‘bulk and body’ and ‘bulk and go’ restorative techniques. Bulk and body: restoring the dentin portion of the cavity with flowable bulk-fill composite (a,b), insertion of enamel composite (c), sculpture (d), and final aspect (e). Bulk and go: insertion of regular bulk-fill composite as single increment (f), accommodation of the increment (g), and final aspect of the sculpture (h).

Figure 8. Examples of ‘bulk and body’ and ‘bulk and go’ restorative techniques. Bulk and body: restoring the dentin portion of the cavity with flowable bulk-fill composite (a,b), insertion of enamel composite (c), sculpture (d), and final aspect (e). Bulk and go: insertion of regular bulk-fill composite as single increment (f), accommodation of the increment (g), and final aspect of the sculpture (h).

Figure 9. Class I restoration using a shade-matching resin composite. Filling irregular areas and rounding internal angles with shade-matching flowable composite (a). Insertion of shade-matching composite to replace dentin (b). Aspect of the artificial dentin after occlusal mapping and design (c). Insertion of the same shade-matching composite for the preparation of dental enamel in a single increment (d). Final aspect of artificial enamel carved in single increment (e). Extrinsic characterization with ochre, brown tints, and dentin composite for bleached teeth emulating regions of large amount of enamel as main lobes of the inclined cuspal planes (f). Final aspect of the restoration (g).

Figure 9. Class I restoration using a shade-matching resin composite. Filling irregular areas and rounding internal angles with shade-matching flowable composite (a). Insertion of shade-matching composite to replace dentin (b). Aspect of the artificial dentin after occlusal mapping and design (c). Insertion of the same shade-matching composite for the preparation of dental enamel in a single increment (d). Final aspect of artificial enamel carved in single increment (e). Extrinsic characterization with ochre, brown tints, and dentin composite for bleached teeth emulating regions of large amount of enamel as main lobes of the inclined cuspal planes (f). Final aspect of the restoration (g).

Table 1. Factors that have significant or limited influences on the clinical longevity of direct resin composite restorations.

Table 1. Factors that have significant or limited influences on the clinical longevity of direct resin composite restorations.

Significant Influence on Longevity Cavity size and volumeGreater loss of dental structure and cavity walls
increases the risk of failures [15]Location of tooth in dental archRestorations in molars fail more often than in premolars, posterior
restorations fail mainly due to fracture and secondary caries, and
esthetic failures are prevalent in anterior restorations [16]Cervical extensionDeep restorative margins increase the risk of failures [17]Enamel etchingWhen enamel is present, etching with
phosphoric acid is recommended [18]Selective removal of carious tissueSelective removal reduces the chances of pulp complications
compared to more aggressive caries excavation methods [19]Endodontic treatmentRestorations in endodontically treated teeth fail more
often than in vital teeth [20]Use of thick cavity linersGlass-ionomer cement layers should be thin (<1 mm); the use of
calcium hydroxide cement may not be necessary in deep cavities [21]Presence of adjacent teethRestorations fail more often when no adjacent teeth are present
or when the restored tooth is the last in the dental arch [22,23]Patient’s age and sexStudies generally report higher risk of restoration failures in
men, children, and elderly patients [24,25]Patient’s risksRisks related to new caries lesions, occlusal stress, periodontal health,
radiotherapy, smoking, dietary habits, and parafunctional habits (e.g., nail biting) increase the chances of failures [13,14,26,27]Frequent change of dentistsChanging dentists increases the risk of unnecessary
interventions and restoration failures [28]Limited Influence on Longevity Restorative techniqueIt is important for the dentist to select a technique that will lead to fewer mistakes, to use few composite increments, to ensure low internal porosity, and provide optimal marginal adaptation and sealing [29,30,31]Adhesive systemSimplified adhesives were usually regarded as having more failures
than 3-step etch-and-rinse and 2-step self-etch adhesives, but current
evidence points out that no significant differences may exist among
different bonding systems [32,33,34]Isolation methodWhen isolation of the operative field is carried out properly, no significant differences in the long term are observed between restorations carried out using a rubber dam or cotton rolls [35]Beveling of enamel marginsIt does not seem to affect the longevity of restorations and
could be used at the dentist’s discretion [36]Resin composite type and brandThe restorative technique and patient-related factors are more important
to the longevity of restorations than material brands or types [7]Polymerization shrinkage of compositesContemporary composites have shrinkage levels compatible with
long-lasting restorative procedures and techniques [37]Finishing and polishing systemAlthough important for the quality of restorations, there is still
insufficient evidence on the effect of different polishing systems
for the longevity of restorationsMarginal stainingMarginal pigmentation does not entail marginal or secondary caries.
Updated caries diagnosis methods and fewer unnecessary interventions will increase the longevity of restorations [7,38]

Table 2. Characteristics of resin composites used for posterior restorations.

Table 2. Characteristics of resin composites used for posterior restorations.

Technique *Type of Resin Composite *CharacteristicsConventional incremental technique (increments typically up to 2 mm in thickness)Microhybrid/NanohybridA resin matrix of dimethacrylate monomers filled with two types/sizes of inorganic particles: nanofillers (<100 nm) and microfillers (>1 μm)Submicron/SuprananoParticle size is above the nano-scale (>100 nm) but below the micro-scale (<1 μm), typically 0.2–0.4 μmNanofillThe filler system contains only discrete
nanoparticles or nano-agglomeratesBulk-fill technique
(increments may be larger than 2 mm in thickness)FlowableA fluid resin matrix of dimethacrylate monomers with low polymerization shrinkage, whose filler particles can be larger than those in conventional composites. The increased translucency allows for photopolymerization of thicker increments. Flowable bulk-fills should be used as a restorative base, which needs to be covered by a final, top layer of conventional compositeRegularSimilar in composition to the flowable composite but with higher viscosity. There is no need for a top layer of conventional composite. Typical increments are up to 4 mm in thicknessMixedComposites with a regular viscosity that may be rendered more fluid through application of sonic vibration. Increments may be up to 5 mm in thicknessOther nomenclatures
for resin compositesUniversalComposites that can be used to restore both anterior and posterior teeth. More recently, the nomenclature has also been used for shade-matching compositesSingle shade or
shade-matchingComposites with chromatic technology for color matching different tooth shades (e.g., from A1 to D4) by using a single resin composite shade