classification of cavity preparation

General DentistryGeneral Dentistry

Chapter 48Chapter 48

Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved.


Lesson 48.1Lesson 48.1


Learning ObjectivesLearning Objectives

Define, spell, and pronounce the Key Terms.Define, spell, and pronounce the Key Terms. Describe the process and principles of cavity Describe the process and principles of cavity

preparation.preparation. Discuss the differences between assisting Discuss the differences between assisting

with an amalgam and with a composite with an amalgam and with a composite restoration.restoration.


IntroductionIntroduction

Restorative and aesthetic dentistry is Restorative and aesthetic dentistry is

focused on the general dental focused on the general dental

needs of the patient.needs of the patient.


Restorative DentistryRestorative Dentistry

Specific conditions that initiate a need for Specific conditions that initiate a need for restorative dental treatment are:restorative dental treatment are: Initial or recurring decay. Initial or recurring decay. Replacement of failed restorations. Replacement of failed restorations. Abrasion or the wearing away of tooth structure.Abrasion or the wearing away of tooth structure. Erosion of tooth structure. Erosion of tooth structure.


Esthetic DentistryEsthetic Dentistry

Specific conditions requiring aesthetic dental Specific conditions requiring aesthetic dental treatment:treatment: Discoloration due to extrinsic or intrinsic staining Discoloration due to extrinsic or intrinsic staining Anomalies due to developmental disturbances Anomalies due to developmental disturbances Abnormal spacing between teeth Abnormal spacing between teeth Trauma Trauma


Terminology in Cavity PreparationTerminology in Cavity Preparation


Initial Cavity PreparationInitial Cavity Preparation

Outline formOutline form Design and initial depth of sound tooth structure Design and initial depth of sound tooth structure

Resistance formResistance form Shape and placement of cavity wallsShape and placement of cavity walls

Retention formRetention form To resist displacement or removalTo resist displacement or removal

Convenience formConvenience form Provides accessibility in preparing and restoring Provides accessibility in preparing and restoring

the tooththe tooth


Final Cavity PreparationFinal Cavity Preparation

Removal of decayed dentin or old restorative Removal of decayed dentin or old restorative materialmaterial

Insertion of resistance and retention with Insertion of resistance and retention with the use of hand cutting instruments the use of hand cutting instruments and burs.and burs.

Placement of protective materials (liners, Placement of protective materials (liners, bases, desensitizing, or bonding) bases, desensitizing, or bonding)


Patient Preparation for Patient Preparation for Restorative Procedures Restorative Procedures

Inform the patient what to expect throughout Inform the patient what to expect throughout the procedure.the procedure.

Position the patient correctly for the dentist Position the patient correctly for the dentist and the type of procedure.and the type of procedure.

Explain each step to the patient as the Explain each step to the patient as the procedure progresses. procedure progresses.


Responsibilities of the Chairside Responsibilities of the Chairside Assistant Assistant

Prepare the setup for the procedures. Prepare the setup for the procedures. Know and anticipate the dentist’s needs.Know and anticipate the dentist’s needs. Provide moisture control.Provide moisture control. Transfer dental instruments and accessories. Transfer dental instruments and accessories. Mix and transfer dental materials. Mix and transfer dental materials. Maintain patient comfort.Maintain patient comfort.


Steps in the Restorative Procedure Steps in the Restorative Procedure

The dentist evaluates the tooth to be restored. The dentist evaluates the tooth to be restored. The dentist administers local anesthesia. The dentist administers local anesthesia. The assistant readies the chosen means of moisture control. The assistant readies the chosen means of moisture control. The dentist prepares the tooth.The dentist prepares the tooth. The dentist determines the type of dental materials. The dentist determines the type of dental materials. The assistant mixes and transfers the The assistant mixes and transfers the

dental materials. dental materials. The dentist burnishes, carves, or finishes the dental material. The dentist burnishes, carves, or finishes the dental material. The dentist checks the occlusion of The dentist checks the occlusion of

the restoration. the restoration. The dentist finishes and polishes the restoration. The dentist finishes and polishes the restoration.


Class I RestorationsClass I Restorations

These restorations are used in class I lesions, These restorations are used in class I lesions, affecting the pits and fissures of the teeth.affecting the pits and fissures of the teeth.

The following surfaces are involved:The following surfaces are involved: Occlusal pits and fissures of Occlusal pits and fissures of

premolars and molars premolars and molars Buccal pits and fissures of Buccal pits and fissures of

mandibular molars mandibular molars Lingual pits and fissures of the maxillary molars Lingual pits and fissures of the maxillary molars Lingual pits of maxillary incisors, most frequently in Lingual pits of maxillary incisors, most frequently in

the pit near the pit near the cingulum the cingulum


Fig. 48-5 Class I restorations.Fig. 48-5 Class I restorations.


Class II Restorations Class II Restorations

A class II lesion is the extension of a class I A class II lesion is the extension of a class I lesion into the proximal surfaces of premolars lesion into the proximal surfaces of premolars and molars.and molars.

The following surfaces are involved:The following surfaces are involved: Two-surface restoration of posterior teeth Two-surface restoration of posterior teeth Three-surface restoration of posterior teeth Three-surface restoration of posterior teeth Four-surface (or more) restoration of posterior Four-surface (or more) restoration of posterior

teeth teeth


Fig. 48-7 Class II restorations.Fig. 48-7 Class II restorations.(From Baum L, et al: (From Baum L, et al: Textbook of operative dentistryTextbook of operative dentistry, ed 3, Philadelphia, 1995, Saunders.), ed 3, Philadelphia, 1995, Saunders.)


Class III and IV Restorations Class III and IV Restorations

Class III lesion Class III lesion Affects the interproximal surface of incisors and Affects the interproximal surface of incisors and

caninescanines Class IV lesion Class IV lesion

Involves a larger surface area, including the incisal Involves a larger surface area, including the incisal edges and interproximal surface of incisors and edges and interproximal surface of incisors and canines canines


Fig. 48-9 Class III composite restoration.Fig. 48-9 Class III composite restoration.


Fig. 48-10 Class IV composite restoration.Fig. 48-10 Class IV composite restoration.


Class V Restorations Class V Restorations

Class V restoration Class V restoration Classified as a smooth-surface restoration. Classified as a smooth-surface restoration.

Decayed lesions occur at:Decayed lesions occur at: Gingival third of the facial or lingual surfaces of Gingival third of the facial or lingual surfaces of

any toothany tooth Root of a tooth, near the cementoenamel junction Root of a tooth, near the cementoenamel junction


Fig. 48-13 A, Class V conventional tooth preparation. B, Fig. 48-13 A, Class V conventional tooth preparation. B, Schematic representation illustrating tooth preparation. Schematic representation illustrating tooth preparation.

(From Roberson T, et al: (From Roberson T, et al: Textbook of operative dentistryTextbook of operative dentistry, ed 4, Philadelphia, 2006, Elsevier.), ed 4, Philadelphia, 2006, Elsevier.)



Lesson 48.2 Lesson 48.2


Learning ObjectivesLearning Objectives

Discuss why retention pins would be selected Discuss why retention pins would be selected for a complex restorative procedure.for a complex restorative procedure.

Describe the need for placement of an Describe the need for placement of an intermediate restoration.intermediate restoration.

Describe the procedure of composite Describe the procedure of composite veneers.veneers.

Describe tooth-whitening procedures and the Describe tooth-whitening procedures and the role of the dental assistant.role of the dental assistant.


Complex Restorations Complex Restorations

Such restorations are required when decay Such restorations are required when decay has extended beyond the normal size or has extended beyond the normal size or shape.shape.

Retention pins Retention pins Decay has extended into the cusp of a tooth and Decay has extended into the cusp of a tooth and

undermined the enamel and dentin. undermined the enamel and dentin. General understanding when using retention pins: General understanding when using retention pins:

One pin is placed for each missing cusp. One pin is placed for each missing cusp.


Fig. 48-14 Retention (retentive) pins placed in tooth structure Fig. 48-14 Retention (retentive) pins placed in tooth structure to help retain and support a restoration.to help retain and support a restoration.


Intermediate Restorations Intermediate Restorations

Restoration placed for a short term.Restoration placed for a short term. Primary factors for placementPrimary factors for placement

Health of the tooth Health of the tooth A wait to receive a permanent restorationA wait to receive a permanent restoration Financial reasons Financial reasons


Procedure 48-5 Placement of intermediate restorative material.Procedure 48-5 Placement of intermediate restorative material.


Direct Bonded Veneers Direct Bonded Veneers

Veneer Veneer Thin layer of tooth-colored material, applied to the Thin layer of tooth-colored material, applied to the

facial surface of a prepared toothfacial surface of a prepared tooth Used to improve the appearance of teeth that Used to improve the appearance of teeth that

are:are: AbradedAbraded ErodedEroded Discolored with intrinsic stainsDiscolored with intrinsic stains Darkened after endodontic treatment Darkened after endodontic treatment


Fig. 48-15 Veneers placed to reduce discoloration and cover stain. Fig. 48-15 Veneers placed to reduce discoloration and cover stain. (From Roberson T, et al: (From Roberson T, et al: Sturdevant’s art and science of operative dentistrySturdevant’s art and science of operative dentistry , ed 4, St Louis, 2002, Mosby.), ed 4, St Louis, 2002, Mosby.)


Fig. 48-16 Veneers placed to close diastema. Fig. 48-16 Veneers placed to close diastema. (From Roberson T, et al: (From Roberson T, et al: Sturdevant’s art and science of operative dentistrySturdevant’s art and science of operative dentistry , ed 4, St Louis, 2002, Mosby.), ed 4, St Louis, 2002, Mosby.)


Tooth Whitening Tooth Whitening

Known as vital bleaching, toothKnown as vital bleaching, tooth whitening whitening

is a noninvasive method of lightening is a noninvasive method of lightening

dark or discolored teeth.dark or discolored teeth.


Indications for Using a Tooth Indications for Using a Tooth WhitenerWhitener

Indications for ProcedureIndications for Procedure Extrinsic stains from foods, cigarette smoking, Extrinsic stains from foods, cigarette smoking,

coffee, or tea coffee, or tea Aged, discolored teeth Aged, discolored teeth Intrinsic stains, such as mild tetracycline stains Intrinsic stains, such as mild tetracycline stains

and mild fluorosis and mild fluorosis


Fig. 48-17 Before-and-after photos of Fig. 48-17 Before-and-after photos of tooth whitening used for extrinsic stains.tooth whitening used for extrinsic stains.


Fig. 48-18 Before-and-after photos Fig. 48-18 Before-and-after photos of tooth whitening used for intrinsic stains. of tooth whitening used for intrinsic stains.

(From Roberson T, et al: (From Roberson T, et al: Sturdevant’s art and science of operative dentistrySturdevant’s art and science of operative dentistry , ed 4, St Louis, 2002, Mosby.), ed 4, St Louis, 2002, Mosby.)


Whitening Products Whitening Products

Chemical makeupChemical makeup Active ingredient Active ingredient

• Either carbamide peroxide or hydrogen peroxide Either carbamide peroxide or hydrogen peroxide

Gel base Gel base • With one or a mixture of propylene glycol, glycerin, and With one or a mixture of propylene glycol, glycerin, and

water water

ThickenerThickener• Carbopol Carbopol


At-Home Tooth-Whitening ProcedureAt-Home Tooth-Whitening Procedure

Material is placed in a thermoplastic custom Material is placed in a thermoplastic custom tray that the patient wears tray that the patient wears for a designated period.for a designated period. With the 10% to 16% carbamide peroxide gels, the With the 10% to 16% carbamide peroxide gels, the

wear schedule is 1 hour twice a day for the first wear schedule is 1 hour twice a day for the first week and once a day for the second week.week and once a day for the second week.

The 20% to 22% mixture is used for 1 hour a day The 20% to 22% mixture is used for 1 hour a day for 2 weeks. for 2 weeks.

Hydrogen peroxide is used for 15 to 30 minutes, Hydrogen peroxide is used for 15 to 30 minutes, two or three times a day, for 2 weeks. two or three times a day, for 2 weeks.


Tooth-Whitening Strips Tooth-Whitening Strips

Thin, flexible strips are coated with Thin, flexible strips are coated with an adhesive hydrogen peroxide whitening an adhesive hydrogen peroxide whitening gel. gel.

ApplicationApplication The patient peels off the backing like a Band-Aid The patient peels off the backing like a Band-Aid

and presses the strip to the facial anterior teeth. and presses the strip to the facial anterior teeth. The remaining portion of the strip is folded onto The remaining portion of the strip is folded onto

the lingual surface. the lingual surface.


Possible Complications to Tooth Possible Complications to Tooth Whitening Whitening

Thermal hypersensitivity Thermal hypersensitivity Patient may experience sensitivity to heat and cold Patient may experience sensitivity to heat and cold

after removal of the tray and material. The use of after removal of the tray and material. The use of toothpaste for sensitive teeth is recommended. toothpaste for sensitive teeth is recommended.

Tissue irritationTissue irritation Gingival tissue exposed to excess gel as a result Gingival tissue exposed to excess gel as a result

of improper tray fit may become irritated. Tell the of improper tray fit may become irritated. Tell the patient not to overfill the tray with material and to patient not to overfill the tray with material and to remove any excess after seating the tray.remove any excess after seating the tray.


Dental Assistant’s Role in Dental Assistant’s Role in Tooth-Whitening ProcedureTooth-Whitening Procedure

Aid in recording the medical and dental history. Aid in recording the medical and dental history. Assist in making shade selection. Assist in making shade selection. Take intraoral photographs before and after Take intraoral photographs before and after

whitening. whitening. Take and pour up preliminary impressions for Take and pour up preliminary impressions for

the tray. the tray. Fabricate and trim the tray.Fabricate and trim the tray. Provide postoperative instructions.Provide postoperative instructions. Assist in weekly or biweekly clinical visits. Assist in weekly or biweekly clinical visits.


Patient Instructions for Patient Instructions for Tooth-Whitening Procedure Tooth-Whitening Procedure

Brush and floss before tray placement.Brush and floss before tray placement. Place equal amounts of gel in tray.Place equal amounts of gel in tray. Seat tray.Seat tray. Do not eat or drink when wearing the tray.Do not eat or drink when wearing the tray. Wear tray for the recommended time.Wear tray for the recommended time. If the patient experiences any problems, If the patient experiences any problems,

discontinue use and discuss with the dentist. discontinue use and discuss with the dentist.


Education

classification of cavity preparation