Dental Restoration Preparation Guidelines

What is one of the reasons for maintaining a minimum degree of divergence of the facial and lingual walls in dental preparations?

What is the purpose of flares in dental preparations?

What is the purpose of placing bevels on the occlusal isthmus with a flame diamond in inlay preparations?

Why is the retention form less critical in ceramic inlays compared to cast gold?

What is a significant consideration for preparation design when using weaker restorative materials for inlays?

In what situations are Class V inlays suitable for use?

Why is it important to avoid creating undercuts where the gingival bevel joins the flares during inlay preparation?

What should be positioned at the height of the crown contour in Class V inlay preparations?

Which of the following is NOT a learning objective of the course?

In the context of the course, what is the duration of the course?

What is the main focus of the topic 'Inlay-Onlay-Endocrown Preparation Techniques' in the course?

According to the mentioned books, who is one of the authors of 'Fundamentals of Fixed Prosthodontics'?

What type of restoration is being compared in the course content?

Which author contributed to the book 'Contemporary Fixed Prosthodontics'?

What is the name of the lecturer for the course?

'Near East University, Faculty of Dentistry' is listed as:

What is the main purpose of inlay and onlay restorations?

Why are inlay restorations considered a great alternative to traditional metallic fillings?

For which type of cavities are inlay restorations strongly recommended?

What is the concern related to high occlusal force and inlay restorations?

Why should all line and point angles in inlay preparations be rounded?

What should be the depth of the preparation for ceramic inlays at the level of the central fossa?

What is the purpose of extending the outline proximally and undermining the marginal ridge in proximo-occlusal cavity restoration with inlay?

What is the main purpose of forming a V-shaped groove at the junction of the axial wall and the gingival floor of the box in inlay preparations?

What is the minimum recommended cervico-occlusal axial wall convergence for cast inlay preparations?

Which material is considered too flexible and may increase the risk of inlay fracture if used as a base material under ceramic inlays?

What aspect must be reduced for an onlay preparation to make it shallower than an inlay preparation?

Which dental restoration is indicated for correcting the occlusal plane of a tooth?

What is the purpose of placing depth orientation grooves on the functional cusps during onlay preparation?

Which restorations require at least one cusp and proximal surfaces, and are more conservative options than full crowns?

What is considered a reasonable consensus for the minimum dimensions of ceramic posterior inlay preparations?

What is the preferred angle for the divergence of box walls during onlay preparation to facilitate optical capture and reduce the risk of excessive binding during seating?

What is the purpose of preparing a 1.0-mm functional cusp ledge with the cylindrical carbide bur?

What is the distinctive feature of endo-crown restoration?

Why is crimping prohibited in endo-crown restoration?

What is the recommended occlusal finish line for the functional cusp of an MOD onlay?

Why is the preparation cavity shape trapezoidal in mandibular molars for endo-crown restorations?

Why are functional cusp beveling made only for metal onlays?

What is the purpose of rounding any sharp line angles, particularly at the junction of the ledge and occlusal surface?

What is the number of appointments required for inlay and onlay indirect restorations?

Define the preparation stages and limits for endo-crown restoration.

List the cavity principles for ceramic inlay restorations.

Compare ferrule-formed and unformed endo-crown restorations in terms of clinical success.

Define the preparation stages and limits for onlay restoration.

Evaluate MOD inlay restoration in terms of susceptibility to complications.

Define the preparation stages and limits for inlay restoration.

Use cavity terminology.

Define the course's main focus in the topic 'Inlay-Onlay-Endocrown Preparation Techniques.'

What is the purpose of creating flares in dental preparations?

Why is the retention form less critical in ceramic inlays compared to cast gold?

What is the recommended occlusal finish line for the functional cusp of an MOD onlay?

What is the main purpose of forming a V-shaped groove at the junction of the axial wall and the gingival floor of the box in inlay preparations?

What is the purpose of rounding any sharp line angles, particularly at the junction of the ledge and occlusal surface?

Why are functional cusp beveling made only for metal onlays?

What is the main focus of the topic 'Inlay-Onlay-Endocrown Preparation Techniques' in the course?

What should be positioned at the height of the crown contour in Class V inlay preparations?

What is the main concern related to high occlusal force and inlay restorations?

What is the purpose of placing a V-shaped groove at the junction of the axial wall and the gingival floor of the box in inlay preparations?

Why is it important to avoid creating undercuts where the gingival bevel joins the flares during inlay preparation?

What is the purpose of extending the outline proximally and undermining the marginal ridge in proximo-occlusal cavity restoration with inlay?

What is considered a reasonable consensus for the minimum dimensions of ceramic posterior inlay preparations?

Why is the retention form less critical in ceramic inlays compared to cast gold?

What is the distinctive feature of endo-crown restoration?

What restorations are strongly recommended for Class-V cavities?

What is the recommended depth of the functional cusp ledge prepared with a cylindrical carbide bur for an MOD onlay?

What is the specific shape of the pulpal floor for endo-crown restorations in mandibular molars?

What is the purpose of placing a 0.5-0.7 mm gingival bevel in inlay preparations?

Why is crimping prohibited in endo-crown restoration?

What is the distinctive feature of endo-crown restoration?

What is the purpose of rounding any sharp line angles, particularly at the junction of the ledge and occlusal surface in onlay preparations?

What is the number of appointments required for inlay and onlay indirect restorations?

What is the preferred occlusal finish line for the functional cusp of an MOD onlay?

What is the minimum recommended cervico-occlusal axial wall convergence for cast inlay preparations?

What is the purpose of placing depth orientation grooves on the functional cusps during onlay preparation?

What is the distinctive feature of endo-crown restoration?

What is one of the reasons for maintaining a minimum degree of divergence of the facial and lingual walls in dental preparations?

What is considered a reasonable consensus for the minimum dimensions of ceramic posterior inlay preparations?

What is the preferred angle for the divergence of box walls during onlay preparation to facilitate optical capture and reduce the risk of excessive binding during seating?

What is the purpose of rounding any sharp line angles, particularly at the junction of the ledge and occlusal surface?

Which material is considered too flexible and may increase the risk of inlay fracture if used as a base material under ceramic inlays?

Lecturer: Assoc. Prof. Dr. Özay Önöral Topic of the Course: Inlay-Onlay-Endocrown Preparation Techniques Duration of the Course: 50 minutes After completion of this course, the student will be able to: Use cavity terminology Define the preparation stages and limits for ______ restoration List the cavity principles for ceramic ______ restorations Evaluate MOD ______ restoration in terms of susceptibility to complications Define the preparation stages and limits for ______ restoration Define the preparation stages and limits for ______ restoration. Compare ferrule-formed and unformed ______ restorations in terms of clinical success

Rounded internal line angles and the butt-joint cavo-surface margins facilitate many aspects of conventional laboratory or chair-side ______ fabrication.

The bulk of ceramic must be established in areas of potential contact from adjacent and opposing teeth, and good visual access to all prepared surfaces facilitates optical capture and subsequent ______.

A minimum cervico-occlusal axial wall convergence of 10°–12° is consistent with general recommendations for ______ preparations.

Often, it is not necessary to remove all undercuts once the desired outline form has been established, as it may be possible to simply block those out on die systems in the dental ______.

Insufficient material thickness will result in ______.

Onlays are indirect restorations that include isthmus, proximal surfaces (mesial, distal or both), and at least one ______.

However, for the cases with high caries rate or for the teeth with short clinical crown height, onlay is ______.

Preparing the boxes is a key step when an onlay is ______.

___ ___ University, Faculty of Dentistry

Code of Committee: CS-___

Lecturer: Assoc. Prof. Dr. Özay ___

Topic of the Course: Inlay-Onlay-Endocrown Preparation ___

Duration of the Course: ___ minutes

Book by Junhei Fujimoto, Martin F. Land, and Stephen F. ___

Learning Objectives of the Course: Use cavity ___

Define the preparation stages and limits for ___ restoration

Inlay and onlay restorations are the minimally-invasive prosthetic approaches, obtained by indirect methods as an alternative to conventional amalgam filing or composite restorations. They are considered within partial crowns. Inlay restorations are indirect restorations that include a part of the clinical crown; isthmus and proximal surfaces of the natural tooth. They are a great alternative to traditional metallic fillings because less of the tooth structure needs to be removed. For the restoration of Class I cavities, the use of ______ is less common as the desired repair can usually be achieved by composite resins. In the restoration of a small carious lesion, an inlay is not very conservative of tooth structure. This is because additional tooth removal is necessary after minimal proximal extension to achieve a cavity preparation without undercuts and to enable access for impression making. This extension may lead to additional display of metal and gingival encroachment, which is undesirable for periodontal health. But for Class-II (only for mesio-occlusal [MO] and disto-occlusal [DO] cavities) and Class-V cavities, inlay restorations are strongly recommended. Because ______ do not encircle the tooth, they rely on the bulk of the buccal and lingual cusps for resistance and retention form.

Preparations for these inlays are meant to provide adequate ______ for the restorative material and a passive insertion pattern with rounded internal angles and well-defined margins. All line and point angles, internal and external, should be rounded to avoid stress concentrations in the restoration and tooth, therefore reducing the potential for fractures. Clinical failures may happen if these undesired stress concentration areas are formed. The most dramatic and common type of this, is the fracture and loss of an entire tubercle. Sometimes the tooth structure can stretch without breaking and the cement layer may break up leading marginal leakage. This creates base for the caries to form. Preparation Principles in Class-II (Proximo-Occlusal) Inlay Restorations While deciding to restore a proximo-occlusal cavity with inlay, the most important factor is the integrity of the proximal surface and the marginal ridge.

The principles in inlay preparation are similar to those in conservative dentistry but there are some characteristic properties. These are; ______ walls, single path of insertion, a smooth base and margin bevels. Occlusal Outline 1. Penetrate the central groove just to the depth of the dentin (typically about 1.8 mm) with a small round or tapered carbide bur held in the path of placement of the inlay. In general, this is perpendicular to an imaginary line connecting the buccal and lingual cusps, not necessarily perpendicular to the occlusal plane. For example, on mandibular premolars, it is angled toward the lingual aspect. 2. The preparation depth shouldn’t be less than 2mm at the level of central fossa for the ceramic inlays, whereas this depth is 1.5mm for composite inlays. 3. The walls of the isthmus will be slightly inclined by the bur used to cut them. There should be pulpal wall but no undercut areas. If undercuts are formed after the preparation, these regions should be restored with Glass Ionomer Liner. 4. Extend the occlusal outline through the central groove with the tapered carbide.

The buccolingual extension should be as ______ as possible to preserve the bulk of the buccal and lingual cusps because an occlusal bevel will widen it later. 6. Resistance to proximal displacement is achieved with a small occlusal dovetail or pinhole. A distinct dovetail extends facially, enhancing resistance and retention. The pulpal floor should be flat, at an even depth of approximately 1.5 mm, and perpendicular to the path of insertion for maximum resistance. The outline should avoid occlusal contacts marked with articulating paper. Proximal Aspect Preparation 7. Extend the outline proximally, undermining the marginal ridge, and stop it at the height of contour of the ridge. 8. Advance the bur cervically (apical direction) to the carious lesion (if any) and then lingually and buccally, taking care to hold it in the precise path of placement. Do not be too ______ with the gingival extension, since this proximal box length is an important factor in the inlay retention. There should be a thin layer of enamel remaining between the side of the bur and the adjacent tooth. This prevents accidental damage.

The gingival floor of the box should be flat. A gingival margin trimmer is used to form a V-shaped groove at the junction of the axial wall and the gingival floor of the box. This groove sometimes referred to as the “______ ditch” is placed to enhance resistance to displacement by occlusal forces. The width of the gingival floor of the box should be about 1.0 mm (mesiodistally). 10. The buccoaxial and linguoaxial line angles of the box are accentuated with a no. 169L bur. The same bur is also used to form the facial and lingual walls of the box, and they are smoothed with an enamel chisel. The box walls, not the angles, resist displacement. The opposing buccal and lingual walls contribute significantly to retention, so great care must be taken not to tilt the bur during this step.

The preparation depth shouldn’t be less than 2mm at the level of central fossa for the ceramic inlays, whereas this depth is 1.5mm for composite inlays. 3. The walls of the isthmus will be slightly inclined by the bur used to cut them. There should be ______ wall but no undercut areas. If undercuts are formed after the preparation, these regions should be restored with Glass Ionomer Liner. 4. Extend the occlusal outline through the central groove with the tapered carbide. 5. The buccolingual extension should be as conservative as possible to preserve the bulk of the buccal and lingual cusps because an occlusal bevel will widen it later. 6. Resistance to proximal displacement is achieved with a small occlusal dovetail or pinhole.

A distinct dovetail extends facially, enhancing ______ and retention. The pulpal floor should be flat, at an even depth of approximately 1.5 mm, and perpendicular to the path of insertion for maximum ______. The outline should avoid occlusal contacts marked with articulating paper. Proximal Aspect Preparation 7. Extend the outline proximally, undermining the marginal ridge, and stop it at the height of contour of the ridge. 8. Advance the bur cervically (apical direction) to the carious lesion (if any) and then lingually and buccally, taking care to hold it in the precise path of placement. Do not be too conservative with the gingival extension, since this proximal box length is an important factor in the inlay retention. There should be a thin layer of enamel remaining between the side of the bur and the adjacent tooth. This prevents accidental damage. 9. The gingival floor of the box should be flat. A gingival margin trimmer is used to form a V-shaped groove at the junction of the axial wall and the gingival floor of the box.

This groove sometimes referred to as the “Minnesota ditch” is placed to enhance resistance to ______ by occlusal forces. The width of the gingival floor of the box should be about 1.0 mm (mesiodistally). 10. The buccoaxial and linguoaxial line angles of the box are accentuated with a no. 169L bur. The same bur is also used to form the facial and lingual walls of the box, and they are smoothed with an enamel chisel. The box walls, not the angles, resist ______. The opposing buccal and lingual walls contribute significantly to retention, so great care must be taken not to tilt the bur during this step.

The bur is oriented parallel to the cuspal inclines. As with all depth grooves, it is assumed that the tooth is in good occlusal relation before preparation. If it is not, a vacuum-formed matrix made from the diagnostic waxing procedure is recommended as a guide. 12. Connect the grooves to form the occlusal reduction, maintaining the general contour of the original anatomy. 13. Prepare a 1.0-mm functional cusp ledge with the cylindrical carbide bur (see Fig. F). This gives the restoration bulk in a high-stress area, preventing deformation during function. The ledge should be placed about 1 mm apical to the opposing centric contacts. It extends into the proximal boxes but should not be positioned too far apically; otherwise, the resistance form from the boxes will be lost. 14. There are 2 acceptable occlusal finish lines for the functional cusp of an MOD onlay: an occlusal shoulder or a heavy ______.

The 0.5-0.7 mm gingival bevel is placed, as for an inlay, with the thin carbide or diamond held at 45 degrees to the path of placement, or approximately parallel to the adjacent tooth contour. This will blend smoothly with the buccal and lingual bevels, which have been prepared with the bur held in the path of placement. 18. Occlusal finishing bevels 0.5 to 0.7 mm are placed at the buccal and lingual occlusal finish lines with a flame diamond followed by a no. 170L carbide bur. The buccal bevel is perpendicular to path of insertion where esthetics are important, and forms a heavier contra-bevel where they are not. Bevel the functional cusps. Where additional bulk at the margin is needed, a ______ should be substituted for the straight bevel. This can be placed with a round-tipped diamond.

For the upper teeth, on the palatal slope of the palatal cusp and for the lower teeth, on the buccal slope of the buccal cusp, a wide bevel is made in order to provide sufficient space for metal thickness. Functional cusp beveling is made only for metal onlays. There is no need to bevel on ceramic or composite ______.

These restorations do not differ from onlays and therefore, can be categorized under onlay restorations. The distinctive feature of endo-crown restoration is that it has to be applied on endodontically-treated natural teeth. The endo-crown is suitable for all molars, particularly those with clinically low crowns, calcified root canals or very slender roots. The endo-crown is contraindicated if adhesion cannot be assured, if the pulpal chamber is less than 3 mm deep or if the cervical margin is less than 2 mm wide for most of its circumference. The butt joint, or cervical sidewalk, is the base of the restoration — with a band of peripheral enamel that optimizes bonding. Unlike chamfer or shoulder preparation techniques, ______ is prohibited.

The goal is to achieve a wide, even, stable surface that resists the compressive stresses that are most common on molars. The prepared surface is parallel to the occlusal plane to ensure stress resistance along the major axis of the tooth. Ferrule-containing endo-crown preparations revealed significantly superior failure loads than regular endo-crown restorations. Moreover, less occurrences of disastrous failure were detected with Endo-crown preparations containing 1 mm of preparation ferrule design. The pulpal chamber cavity ensures retention and stability. Its shape — trapezoidal in mandibular molars and triangular in maxillary molars — enhances the restoration’s stability. There is no need for additional preparation. The saddle form of the pulpal floor enhances stability. This anatomy, along with the adhesive qualities of the bonding material, makes it unnecessary to attempt further use of post involving root canals. Actually, the root canals do not require any specific shape; therefore, they are not weakened by the drilling and they will not be subject to the stresses associated with the use of ______.

They require 2 appointments; during the first visit, damaged or decayed area is removed and the tooth is prepared in accordance with the principles of inlay or onlay. An impression (conventionally or digitally) is taken and sent to the laboratory for fabrication. During the second visit, the restoration is bonded to the tooth with the aid of ______ cements.

The compressive stresses are reduced, being distributed over the cervical butt joint and the walls of the pulp chamber. NUMBER OF APPOINTMENTS IN INLAY AND ONLAY INDIRECT RESTORATIONS They require 2 appointments; during the first visit, damaged or decayed area is removed and the tooth is prepared in accordance with the principles of inlay or onlay. An impression (conventionally or digitally) is taken and sent to the laboratory for fabrication. During the second visit, the restoration is bonded to the tooth with the aid of ______ cements.

The endo-crown is contraindicated if adhesion cannot be assured, if the pulpal chamber is less than 3 mm deep or if the cervical margin is less than 2 mm wide for most of its circumference. The butt joint, or cervical sidewalk, is the base of the restoration — with a band of peripheral enamel that optimizes bonding. Unlike chamfer or shoulder preparation techniques, ______ is prohibited.

Ceramics are brittle. Though significant progress has been made in the development of new and improved materials, the inherent brittleness remains a limiting factor that can be minimized through proper preparation design. Preparation guidelines for ceramic inlays differ from those for cast gold. Retention form is not as critical due to the bonded nature of the restoration, and ______ are contraindicated.

The walls are prepared slightly-angled and meet the enamel with a right angle at the edge of the cavity. Pin slots are opened 2mm in depth in places that will not damage the pulp and in the parts where there is sufficient tooth tissue, with a 0.6 mm bur. A narrow ______ is made at an angle of 45° on the cavity walls.

Prepare proximal ______ on the buccal and lingual walls with the tapered bur oriented in the path of placement. There should be a smooth transition between the proximal and gingival ______.

The inlay preparation is finished by placing a ______ on the occlusal isthmus with a flame diamond. If a shallow ______ is used in this location, the result will be a thin flash of metal that will probably extend into areas of occlusal contact.

The ______ must be minimal, because compressive stress increases as the inclination of the ______ increases. The ______ is likely to produce a finish-able casting. Blend the occlusal ______ into the proximal flares to produce a smooth, continuous finish line. Use a flame carbide bur to go over the flares and the ______s. The flame bur produces the most consistent ______, and carbide finishing burs will produce the smoothest finish lines. A torpedo diamond can be used to create the ______.