[263] Teeth interventions for restoration * Loss of tooth structure * Tooth fracture compromisng form and function * Congenital malformation or improper position * Previous restoration with inadequate occlusal or defective or poor esthetic * Other
I. conserve as much healthy tooth structure as possible, II. remove all defects while simultaneously providing protection of the pulp–dentin complex, III. form the tooth preparation so that, under the forces of mastication, the tooth or the restoration (or both) will not fracture and the restoration will not be displaced and IV. allow for the esthetic placement of a restorative material where indicated.
Patient factors • Desires • Home care • Risk status • Age • Cooperation • Anesthesia
Anatomical factors • Enamel rod orientation • Dentin thickness • Pulp location • Coronal contours • Extent of previous restoration
Procedural factors • Operator skill • Instrument design • Type of rotary cutting instrument • Ability to isolate
Lesion/defect factors • Bone support • Occlusion • Severity • Gingival status • Pulpal status • Fracture development
Restorative material factors • Physical properties • Colour characteristics • Cost-effectiveness
// Shafers
Types of restoration¶
amalgam¶
Indications of Amalgam¶
Amalgam is used for the
... Restoration of carious or fractured posterior teeth as Class I and Class II restorations;. ... Replacement of failed posterior restorations; ... As a foundation restoration; ... As a caries control restoration ... Due to its strength and ease of use, amalgam may be used (not commonly though) for restoring large defects in nonesthetic areas and areas with isolation problems (certain Class III and Class V situations).
Contraindications¶
... Amalgams are contraindicated in patients who are allergic to alloy components. ... The use of amalgam in more prominent esthetic areas of the mouth may represent a relative contraindication. These areas include anterior teeth and, in some patients, premolars and molars. ... Amalgam should not be used when composite resin would offer more conservation of tooth structure and equal clinical performance.
Advantages¶
Some of the advantages of amalgam restorations already have been stated, but the following list presents the primary reasons for the successful use of amalgam restorations over many years: ... Ease of use ... High compressive strength ... Excellent wear resistance ... Favourable long-term clinical research results ... Lower cost than for composite restorations
Disadvantages¶
The primary disadvantages of amalgam restorations relate to esthetics and increased tooth structure removal during tooth preparation. The following is a list of these and other disadvantages of amalgam restorations: ... Non-insulating ... Nonesthetic ... Less conservative tooth preparation than for composite restorations (more removal of tooth structure during tooth preparation) ... More difficult tooth preparation than for composite restorations Initial marginal leakage The following sections begin with the introduction of general clinical techniques and associated concepts to be considered when restoring caries lesions or defects with dental amalgam. The general technique is then followed by specific discussion addressing the creation of Class I and Class II restorations. Readers are referred to Chapter 14 for complex amalgam restorations and to Online Chapter 26 for more information on Class III and Class V amalgam restorations. V.
Complex amalgam restoration¶
Indications¶
Complex posterior restorations are indicated when tooth structure is missing due to cusp fracture, severe caries lesion development or when replacement of existing restorative material is necessary. Complex amalgam preparations should be considered when large amounts of tooth structure are missing, when one or more cusps need to be covered and when increased resistance and retention forms are needed (Fig. 14.1).1 Complex amalgams may be used as follows: ... Definitive (final) restorations Usually a weakened tooth is best restored with a properly designed indirect (usually cast) restoration that prevents tooth fracture caused by mastication forces (Chapter 23). In selected cases, amalgam preparations that improve the resistance form of a tooth may be designed (Fig. 14.2). When conventional retention features are not adequate because of insufficient remaining tooth structure, the retention form may be enhanced by using auxiliary features such as slots and pins. The type of retention features needed depends on the amount of tooth structure remaining and the tooth being restored. As more tooth structure is lost, more auxiliary retention is required. Slots and pins provide additional resistance and retention form to the tooth when remaining vertical walls are inadequate. ... Foundation restoration Although complex amalgam restorations are used occasionally as an alternative to indirect restorations, particularly due to cost savings, they are often used as foundations for full-coverage restorations. Abutment teeth for fixed prostheses may use a complex restoration as a foundation (Fig. 14.3). ... Control restorations in teeth that have a questionable pulpal or periodontal prognosis A tooth with a severe caries lesion that may require endodontic therapy or crown lengthening or that has an uncertain periodontal prognosis is often treated initially with a control restoration. A control restoration helps i. protect the pulp from the oral cavity (i.e. fluids, thermal stresses, pH changes, bacteria); ii. provide an anatomic contour that is consistent with gingival health; iii. facilitate control of acidogenic biofilm and resultant caries risk; and iv. provide some resistance against tooth fracture (or propagation of an existing fracture). (See Chapter 2 for caries-control rationale and techniques.) Figure 14.1 Mesioocclusodistolingual (MODL) complex amalgam in a maxillary first molar. The status and prognosis of the tooth determine the size, number and placement of retention features. Larger restorations generally require more retention. The size, number and location of retention features demand greater care in smaller teeth. Carelessness may increase the risk of pulpal irritation or exposure. IV. Interim restoration Complex amalgam restorations are sometimes indicated as interim restorations for teeth that require elaborate occlusal alterations, ranging from vertical dimension changes to correcting occlusal plane discrepancies. When cost of indirect restorations is a major factor for the patient, the complex direct amalgam restoration may be an appropriate treatment option, provided that adequate resistance and retention forms are included (Fig. 14.4).2,3 For some older patients and/ or those who are debilitated, complex amalgam restoration may be the treatment preferred over the more expensive and time-consuming indirect restoration.
Contraindications¶
The complex amalgam restoration may be contraindicated: I. if the tooth cannot be restored properly with direct restoration because of anatomic or functional considerations (or both); II.if the area to be restored has esthetic importance for the patient.
Advantages Conservation of Tooth Structure The preparation for a complex amalgam restoration is usually more conservative than the preparation for an indirect restoration. Appointment Time The complex restoration may be completed in one appointment. An indirect restoration generally requires at least two appointments unless it is done using a chairside computer-aided design/computer-assisted manufacturing (CAD/CAM) system. Resistance and Retention Forms Amalgam restorations with cusp coverage significantly increase the fracture resistance of weakened teeth compared with amalgam restorations without cusp coverage.4 Resistance and retention forms may be significantly increased by the use of slots and pins (discussed in subsequent sections).
Reduced Cost The complex amalgam restoration may be utilized to reinforce and stabilize compromised posterior teeth at a much reduced cost to the patient. It may serve as a definitive final restoration or an intermediate-term restoration with a long-term goal of indirect, more costly restoration and protection of the tooth. Disadvantages Tooth Anatomy Proper contours and occlusal contacts and anatomy are sometimes difficult to achieve with large, complex restorations. Resistance Form Resistance form is more difficult to develop with a complex amalgam as compared to the preparation of a tooth for a cusp-covering onlay (skirting axial line angles of the tooth [Chapter 23]) or a full crown. The complex amalgam restoration does not protect the tooth from fracture as effectively as a full-coverage indirect restoration
composite¶
indications¶
The indications for direct composites are: ... Class I, II, III, IV, V and VI restorations. ... Foundations and core buildups. ... Sealants and preventive resin restorations (conservative composite restorations). ... Esthetic enhancement procedures: . Partial veneers . Full veneers . Tooth contour modifications . Diastema closures ... Temporary or provisional restorations. ... Periodontal splinting. ... Luting of indirect esthetic restorations (when used in flowable form, or when heated to increase flow).
contraindications¶
The primary contraindications for use of direct composites relate to: I. II. Inability to obtain adequate isolation. Occlusal considerations related to wear and fracture of the composite material. III. Extension of the restoration on root surface. IV. Operator factors. If the operating site cannot be isolated from contamination by oral fluids, composite (or any other bonded material) should not be used. If all of the occlusion is on the restorative material, composite may not be the choice for use particularly in patients with heavy occlusal function; however, the need to strengthen remaining weakened unprepared tooth structure with an economical composite restoration procedure (compared with an indirect restoration) and the commitment to recall the patient routinely and in a timely manner may override any concern about excessive wear potential. Any restoration that extends onto the root surface may result in less than ideal marginal integrity. Lastly, the operator must be committed to pursuing procedures, such 496 as tooth isolation, that make bonded restorations successful. These additional procedures may make successful bonded restorations more difficult and time consuming to achieve.
advantages¶
The following are advantages of composite restorations: I. Esthetics II. Conservative tooth preparation (less extension, minimum depth not necessary, mechanical retention usually not necessary) III. Low thermal conductivity IV. Universal use V. Adhesion to the tooth VI. Repairability. The primary disadvantages of composite restorations relate to their dependence on adequate adhesion and polymerization protocols and procedural difficulties. Composite restorations: I. May have poor marginal and internal cavity adaptation, usually occurring on root surfaces as a result of polymerization shrinkage stresses or improper insertion of the composite. II. May exhibit marginal deterioration over time in areas where no marginal enamel is available for bonding. III. Are more difficult and time consuming to place, and more costly (compared with amalgam restorations) because bonding usually requires multiple steps; insertion is more difficult; establishing proximal contacts, axial contours, embrasures and occlusal contacts may be more difficult and finishing and polishing procedures are more difficult. IV. Are more technique sensitive because the operating site must be appropriately isolated, incremental placement technique must be used for most materials and proper adhesive technique is absolutely mandatory. V. May exhibit greater occlusal wear in areas of high occlusal stress or when all of the tooth’s occlusal contacts are on the composite material.
Direct Gold restoration¶
Indications¶
I.Class I direct gold restorations are one option for the treatment of small carious lesions in pits and fissures of most posterior teeth and the lingual surfaces of anterior teeth. II. Direct gold also is indicated for treatment of small, cavitated Class V carious lesions or for the restoration, when indicated, of abraded, eroded or abfraction areas on the facial surfaces of teeth (although access to the molars is a limiting factor). III. Class III direct gold restorations can be used on the proximal surfaces of anterior teeth where the lesions are small enough to be treated with esthetically pleasing results. IV. Class II direct gold restorations are an option for restoration of small cavitated proximal surface carious lesions in posterior teeth in which marginal ridges are not subjected to heavy occlusal forces (e.g. the mesial or distal surfaces of mandibular first premolars and the mesial surface of some maxillary premolars). Class VI direct gold restorations may be used on the incisal edges or cusp tips. VI. A defective margin of an otherwise acceptable cast gold restoration also may be repaired with direct gold. Contraindications Direct gold restorations are contraindicated in some patients whose teeth have: I. Very large pulp chambers II. Severely periodontally weakened teeth with questionable prognosis III. Patients for whom economics is a severely limiting factor IV. In handicapped patients who are unable to sit for the long dental appointments required for this procedure V. Root canal-filled teeth are generally not restored with direct gold
Material qualities and properties important for class III and V amalgam restorations are strength, longevity, ease of use and past success. (See Chapter 12 for a discussion of the pertinent material qualities and properties of amalgam.)
Indications Few indications exist for a class III amalgam restoration. It is generally reserved for the distal surface of maxillary and mandibular canines if (i) the preparation is extensive with only minimal facial involvement, (ii) the gingival margin primarily involves cementum or (iii) moisture control is difficult. For esthetic reasons, amalgam rarely is indicated for the proximal surfaces of incisors and the mesial surface of canines. Class V amalgam restorations may be used anywhere in the mouth. As with class III amalgam restorations, they are generally reserved for non-esthetic areas, for areas where access and visibility are limited and where moisture control is difficult and for areas that are significantly deep gingivally. Because of limited access and visibility, many class V restorations are difficult and present special problems during the preparation and restorative procedures. One measure of clinical success of cervical amalgam restorations is the length of time the restoration serves without failing (Online Fig. 26.3). Properly placed class V amalgams have the potential to be clinically acceptable for many years. Some cervical amalgam restorations show evidence of failure, however, even after a short period. Inattention to tooth preparation principles, improper manipulation of the restorative material and moisture contamination contribute to early failure. Extended service depends on the operator’s care in following accepted treatment techniques and proper care by the patient. Amalgam may be used on partial denture abutment teeth because amalgam resists wear as clasps move over the restoration. Contours prepared in the restoration to retentive areas for the clasp tips may be achieved relatively easily and maintained when an amalgam restoration is used. Occasionally, amalgam is preferred when the caries lesion extends gingivally enough that a mucoperiosteal flap must be reflected for adequate access and visibility (Online Fig. 26.4). Proper surgical procedures must be followed, including sterile technique, careful soft tissue management and complete debridement of the surgical and operative site before closure. Contraindications Class III and V amalgam restorations usually are contraindicated in esthetically important areas because many patients object to metal restorations that are visible (Online Fig. 26.5). Generally, class V amalgams placed on the facial surface of mandibular canines, premolars and molars are not readily visible. Amalgams placed on maxillary premolars and first molars may be visible. The patient’s esthetic demands should be considered when planning treatment. Advantages Amalgam restorations are stronger than other class III and V direct restorations. In addition, they are generally easier to place and may be less expensive to the patient. Because of its metallic colour, amalgam is easily distinguished from the surrounding tooth structure. Amalgam restorations are usually easier to finish and polish without damage to the adjacent surfaces. Disadvantages The primary disadvantage of class III and V amalgam restorations is that they are metallic and unesthetic. In addition, the preparation for an amalgam restoration typically requires 90-degree cavosurface margins and specific axial depths that allow incorporation of secondary retentive features. These features result in a less conservative preparation than that required for most esthetic restorative materials.