Introduction to Operative Dentistry Cavity Classification and Nomenclature PDF

Introduction to Operative Dentistry Cavity Classification and Nomenclature BY: Asmaa khater Introduction to Operative Dentistry Definition: “Operative dentistry is defined as science and art of dentistry which deals with diagnosis, treatment and prognosis of defects of the teeth which do not requi...

Introduction to Operative Dentistry Cavity Classification and Nomenclature BY: Asmaa khater Introduction to Operative Dentistry Definition: “Operative dentistry is defined as science and art of dentistry which deals with diagnosis, treatment and prognosis of defects of the teeth which do not require full coverage restorations for correction.” Such corrections and restorations result in the restoration of proper tooth form, function and esthetics while maintaining the physiological integrity of the teeth in harmonious relationship with the adjacent hard and soft tissues. Such restorations enhance the dental and general health of the patient Objectives of operative dentistry: The objectives of operative dentistry are now broadened to include both preservation and prevention. 1. Operative dentistry aims at the prevention of dental disease and is concerned with the preservation of the natural teeth and their supporting structures in an optimal state of health to avoid their future loss or extraction. Proper diagnosis of lesions, including their locations and extent, is vital for planning the treatment 2- the application of all procedures for prevention before the appearance of any sign and symptom of disease. also 3- interception; in order to prevent the disease from developing into a more serious or full extent, It provides the capability of restoring teeth to their natural form, function, strength and esthetic state 4- Preservation of optimum health of teeth and soft tissue of oral cavity is obtained by preventive and interceptive procedures 5- Restoration;  These restorative procedures have both scientific and artistic foundation.  It is important to understand anatomy of teeth because of following reasons: For maintenance of supporting tissues in the healthy state. For restoration of damaged tooth to its original form and ethetic. For optimal functions of teeth. 6. Maintenance; After restoration is done, it must be maintained for longer useful service.  Cavity Classification and Nomenclature A cavity is:  a defect in the hard tooth structure resulting from dental caries.  The cavity is surgically opened to expose the carious lesion.  the carious material is removed and the cavity is given a form that will assure; 1- proper retention for the restorative materials, 2-adequate resistance to fracture during function, 3- immunity from the recurrence of caries at the margins of the restorations and protection for the vital pulp.  Caries is more liable to occur in certain areas in teeth than others, these areas favor accumulation of food debris and are rather difficult to keep clean by the patient. Areas of liability to caries: (danger areas) Stagnation areas in which food collects and undergoes fermentation by bacteria present in the mouth in huge amounts. This fermentation will lead to acid production which is responsible for decalcification of enamel and caries process will start and as a result a cavity will be established.  1. Pits and fissures:  These are enamel defects or faults which result from incomplete union of enamel lobes during formation of enamel.  A pit results from incomplete union of three enamel lobes, while a fissure results from incomplete union of two lobes of enamel during the formative period of enamel. If a complete union occurs between two enamel lobes the results will be a groove, while complete union between three enamel lobes will lead to the formation of a fossa 2. Areas in the proximal surface below the contact point( subcontact area):  The proximal surfaces of the teeth are smooth surfaces because there are no pits or fissures present.  Areas between two adjoining teeth are a place where food debris can stagnate and ferment, hence each tooth has a danger area just below its contact point where interproximal cavities occur.  Since the shape and the relative position of each tooth in relation to the adjoining teeth in normal dentition reduce the liability to caries to a great extent, it is essential to restore the proximal surface of any tooth to its normal contour very accurately. 3. Areas below the greatest diameter of the tooth (Buccal deflection ridge), (In the cervical third of the buccal and lingual surfaces of the teeth). These areas provide a shelf for food debris. These areas are smooth surfaces, as no pits or fissures are found. Classification of cavities It can be classified into groups considering A) Anatomical classification: According to location B) Black’s classification: according to the site C). Numerical classification: Classified according to the number of surface affected by caries D) Mount and Hume’s classification: based on the site and the size (stage) of the lesion 1. (Anatomical classification) Pit and fissure caries: Pit and fissure caries occur on occlusal surface of posterior teeth and buccal and lingual surfaces of molars and on lingual surface of maxillary incisors. Smooth surface caries: Smooth surface caries occurs on gingival third of buccal and lingual surfaces and on proximal surfaces. Root caries: When the lesion starts at the exposed root cementum and dentin, it is termed as root caries. B) Black’s classification Class I: Pit and fissure caries occur in the occlusal surfaces of premolars and molars, the occlusal two third of buccal and lingual surface of molars, palatal surface of upper incisors. Class II: smooth surface Caries occur in the proximal surface of posterior teeth (premolars and molars). Class III: smooth surface Caries occur in the proximal surface of anterior teeth (incisorsmand canine) teeth and not involving the incisal angles. Class IV: smooth surface Caries occur in the proximal surface of anterior teeth also involving the incisal angle. Class V: smooth surface Caries occur in the gingival third of facial and lingual or palatal surfaces of all teeth. Class VI: Caries on incisal edges of anterior and cusp tips of posterior teeth without involving any other surface C) Numerical classification(Sturdevants classification):  Simple caries: Caries involving only one tooth surface  Compound caries: If two surfaces are involved.  Complex caries: If more than two surfaces are involved it is called as complex caries. D) Mount and Hume's classification: Black's classification has been challenged as being not specifying the size of the lesion. Mount and Hume in 1998 have introduced a new classification (digital classification) that is based on the site and the size of the lesion and called Si / Sta classification referring to the site and stage of the lesion. The three sites are: Site 1: for pits and fissures and enamel defects. Site 2: involve approximal enamel surfaces. Site 3: it includes the cervical one third of the crown or, following gingival recession, the exposed root. The four sizes are: Size 1 : indicates minimal dentin involvement. Size 2: indicates moderate dentin involvement. Size 3: indicates enlarged involvement beyond moderate. Size 4: indicates an extensive involvement of caries and bulk loss of tooth structure. Components of prepared cavities: ‫إعداد‬  Preparation of cavities results in the formation of various walls, lines and angles.  The following terms are used to describe a prepared cavity and its various components. A wall is an enclosing side of a prepared cavity. It takes the name of the surface of the tooth toward which is placed. the axial wall: In an axial plane (long axis of the tooth) the internal wall (parallel to the long axis of the tooth) and approximating the pulp pulpal wall: That wall of the prepared cavity which is to the occlusal surface of the pulp and in a plane at right angles to the long axis of the tooth (horizontal plane) A line angle: is formed where two walls meet. At the place where three walls meet, a point angle is formed The cavosurface angle: is the angle in a prepared cavity formed by the junction of the wall of the cavity with the uncut surface of the tooth. The cavo-surface angle of a cavity will be composed of enamel, but in cavities present in the root of teeth which are exposed due to gingival recession the cavo-surface angle will be of cementum. The enamel margin includes the whole outline of the prepared cavity The term margin is used to describe the cavosurface angle of a prepared cavity and / or to designate the line of junction of the tooth surface and the restoration after the restorative material is placed. The dentino-enamel junction: is the junction of the dentin and enamel as it appears in the walls of the prepared cavity. The enamel wall: is that portion of the wall that consists of enamel. It extends from the cavosurface margin or angle to the dentino enamel junction. The dentin wall: is that portion of a wall that consists of dentin. The peripheral extent of the cavosurface angle of the prepared cavity is termed the outline form of the cavity