OPERATIVE DENTISTRY

Done by :

Rajaa samarji

Riham moustafa

Nada Rihani

Nouranne zahran

Habib sabbah

Advanced Tools In Restoring Compound Cavities

• Introduction :

• Cavities are classified into :

Simple compound complex

Compound cavities are cavities that include two surfaces of the tooth , and , due to this , undergo the most complications in the filling procedure .

Abbreviation for Two-Surface Restorations (Compound Cavity Restorations )

OB Occluso-buccal

MO Mesio-occlusal

DO Disto-occlusal

DL Disto-lingual

MI Mesio-incisal

LI Linguo-incisal

Earlier to any restorative practice undertaken , a suitable cavity preparation is mandatory.

This clinical step is the mechanical change of the tooth to accept a restorative material with which a satisfactory form, function and appearance of the tooth is obtained.

Lately enhancements in materials and techniques have been devised and new skills are now present for this reason. Recently a CVD coated diamond bur coupled to an ultrasonic handpiece is used in dental preparation. This technique offers a precise and conservative tooth preparation with ultimate access and visibility and because of improved efficiency can also aid in the removal some of the patient distress to the dental treatment.

• At present, there are some different approaches of cutting enamel and dentin

1).Air abrasive instruments , have not extended to common clinical acceptance because of the obstacles of eliminating residual aluminum oxide dust

2) Another alternative method is the use of laser cutting. Currently, the ErYAG laser’s capability to ablate dental tissue efficiently, owing to transmission of specific wavelengths absorbed by water and hydroxyapatite, is observed as the most efficient laser. The little knowledge and the high cost of the equipment has limited its use. This technology is available to the dentists, but can only be used successfully when clinicians have the proper information necessary to use them appropriately, and know their benefits as well as their disadvantages.

3)presently, a special diamond coated bur coupled to an ultrasonic handpiece for dental applications was established, by covering a molybdenum substrate through a Chemical Vapor Deposition (CVD) process. This bur is termed CVD by the manufacturer• CVD characteristics :

1)characterized by a pure diamond cutting surface without a metallic binder between crystals

2)These burs can be adjusted by a suitable mandrel to almost any ultrasonic handpiecesystem found, generating a cutting speed about half that of a conventional rotary instrument.

Conclusion:• The ultrasound-coupled CVD bur was observed as an effective technique for tooth

preparation especially compound cavity preparation in this instance. It was effective and harmless for working close to the gingival margin, and upgraded the operating areaavisibility, because of access inclination angles that are not available when using a conventional handpiece.

• The ultrasonic preparation method also relieves the patient from psychological factors that accompany conventional rotary instruments noise. Consequently, the ultrasonic cavity preparation using CVD coated diamond bur provides hopeful clinical utility for certain dental procedures.

Exploring or diagnostic instruments

Isolating Instruments

Hand cutting instruments

Restoring instruments

Miscellaneous instruments

1-Mouth mirror2-explorer or probe

-straight probe

-right angled probe

- Arch shaped (shepherds hook)

- interproximal (back action)3- Tweezers 4-Seperators 5-cheek retractors6- Air syringe

1-cotton roll holder2-Rubber dam 3-Saliva ejector 4- Suction apparatus

1-Excavators-Spoon

excavator-cleiod-discoid - Hatchet

excavator -Hoe

2- Chisels Straight chisel Mono angle chisel Bin angle chisel Triple angle chisel 3- Modified chisels

- Wedelsteadt chisel

-Enamel hatchet -Ginigival margin

4- Trimmer Angle former

Mixing instrument -Cement spatula -Agate spatula

2-Plastic carrying/filling instruments3-Packing instruments

-Amalgam carrier 4-Condensing instruments :

-Round condenser

-parallelogram condenser5-Burnishing instruments

-Ball shaped -Egg shaped - Conical shaped

6- Carving instruments -Hollenback carver -Diamond carver-Wards carver

1-Matrices and retainers 2-Scissors

Diagnostic tools : Isolating instruments

Hand cutting instruments : Restoring instruments :

Instruments that are of most importance in restoration of compound cavities :

A- Dental Matrix :

Definition:

-It is a device used to contour a restoration to simulate that of a tooth structure, which it is replacing, and it can be defined as; a device during restorative procedures to hold the plastic restorative with in the tooth while it is setting.

-Matricing is procedure whereby a temporary wall is created opposite to axial walls, surrounding areas of the tooth structure that were lost during the cavity preparation.

-There is no method to control the placement and contour of restoration without a matrix wall.

Evolution of matrix bands

• Matrices were linear bands that the dentist had to bend them in order to obtain a form that encircles the tooth

• The shape has been modified, in sizes and finally taking the shape of the tooth.

• Classification :I-Based the mode of retentiona)with retainer eg. tofflemire, ivory no. 1 and ivory no. 8 matrices b)without retainer eg. automatrixII-Based on type of band material:a)Celluloid b)cellulose acetate(cellophane)c)cellulose nitrate(mylar)d)copper bandIII-Based on its preparation:a)custom made or anatomic matrix eg. compound supported matrix b)mechanical matrix eg. tofflemire, ivory no. 1 and ivory no.8 matricesIV-Based on transparency :

I-Based on the mode of retention

a) With a retainer

Ivory NO.1 matrix:

-Consists of a stainless steel band which encircles one proximal surface of a posterior tooth.

Ivory NO.8 matrix:

-Consists of a band that encircles the entire crown of the tooth.

Tofflemire matrix: (Universal matrix)

-This is the most recent development and is usually preferred for most class II amalgam restoration.

b)Without retainer

-Automatrix:-It is a retainerless matrix system.

-Automatrix bands are available in thickness of 0.0015 to 0.002 inch. and they may be of 3 widths

-They may be selected according to the height of the tooth to be restored

-Bands are already formed into a circle and are available in assorted sizes in both metallic and plastic

II-Based on type of band material a)Celluloid (Cellulose nitrate) strips are used for silicate cementsb)Cellophane (Cellulose acetate) strips are used for resinsc)Mylar strip are used for composite for composite and silicate restorations For Class IV tooth preparation, the strip is folded in ‘L –shaped) Copper band matrix:-These are cylindrical in shape and can be selected according to the diameter of the tooth to be restored.-The band are softened by heating to redness in a flame and quenching in water-After condensation and carving to the amalgam the band is left in place. it is sectioned and removed at the next appointment.

© (d)

III-Based on its preparation :

a) Compound supported matrix:(Custom made or anatomical matrix)

-Its is entirely hand made and is contoured specifically for indivdual cases.

-Following this amalgam condensation and carving can be done.

-To be removed the matrix the compound can be broken away with a sharp explorer and the matrix strip can be removed.

b) Mechanical matrix :eg. tofflemire, ivory no. 1 and ivory no.8 matrices

IV- Based on transparency :

a) Transparent :Transparent plastic crown form matrix:

-They are available in various sizes and contours for anterior teeth

-The bulk of the composite resin is loaded into the crown form. This is then positioned over the crown form and then placed over the tooth and light cured. Thus the contours of the tooth can be shaped easily. After curing , the crown form can be slit with a bur and removed.

Preformed transparent cervical matrix:

-Used in anterior and posterior teeth.

-They are designed for use with light cured composite resins or GIC’s.

-A tweezer or a handle can hold the matrix in place while the restoration is hardening.

• RECENT PRODUCTS1. V3 Matrix (Triodent) –Pronounced ridge

on the occlusal margin with rolled

edge for marginal ridge buildup.

2.Convexi-T Convex Tofflemire

matrix band (Clinician’s choice) –Precontoured

buccally/ lingually and occlusally/ gingivally.

. They facilitate the creation of

interproximal contours .

3.SuperMat(Kerr) –Universal matrix

tensioning system designed to

facilitate large-scale direct restoration of posterior

teeth.

4.Fender Mate flexible wing (DirectaAB) –Separates the teeth, pressing the matrix toward the cervical margin, avoiding overhang.Optimal curvature and preshaped contact.

5.Composi-Tight 3D SectionalMatrix System (Garrison Dental Solutions)

–Soft Face 3D-Ring with contoured soft-siliconefaces that mold sectional matrixbands to the teeth.

6.Slick Bands (Garrison Dental Solutions) –Preventbonding agents from sticking to the matrixband by applying a micro thin coating to

their stainless steel matrix bands.7.Omni-Matrix Sectional (Ultradent) - 4 distinctmatrix bands that are extremely thin and flexible.

WEDGES :

-Third component of the matrix system.

-Wedging provides rapid or immediate separation. The separation achieved is based on the wedging principle.

Wedges are made of:

- Wood, Plastic or celluloid, Metal,Silver, Medicated wooden wedges .

Wooden wedges are preferred because They are easy to trim with a scalpel and they adapt well to the tooth surface. When properly shaped they remain stable during condensation. Also absorb moisture and swell to provide adequate stabilization.

Shapes:

Triangular or round

The wedge ought not infringe towards the contact range: this will misshape the network and leave a huge approximal hole under the contact point.

In areas of difficult anatomy (eg: canine furrow on mesial part of Upper first premolars) more than one wedge may be required to seal pit.

• The injection-Molded technique • Before starting the method, if a lot of dentin is available, that dentin is either secured with glass ionomer

or dentin holding operators.

• The injection-molded composite dentistry method calls for first applying bonded resin to both the beforehand treated dentin and the recently etched enamel inside the matrix

• then infusing a flowable composite into the pool of the supporting resin, and after that at last infusing the paste composite.

• The resin-flowable-paste mass is polymerized together in a solitary light-cure.

• In the creator's procedure, he aims for the paste composite to make up 80% to 90% of the general volume of the filling, while flowable ought to represent 10% to 20%. With customarily square shaped preparations, it is basic to see restorations with 50% to 70% of the general volume made up by flowablecomposite.

• That sum of flowable can add to unsatisfactorily high rates of marginal ridge fracture and complete filling dislodgement.

• New materials

• New materials

• The EQUIA™ Fil is a bulk

filled with radiopaque posterior restorative

material in capsules.

• The material used is called Verionomer.

A coat is needed after finishing

the filling to protect the

material. Verionomer has

higher rate of wear than Composite and Amalgam.

An upside to using this

material, is that there is a low

percentage of breaking the

tooth where there is a wall thin

enough to be removed in the

normal case of using Composite or Amalgam.

This procedure takes less time and is more accurate compared to manual mixing of GC Fuji X 9.