The Vector Method

Tips and tricks forminimal invasivecavity preparationwith the Vector system

The Vector MethodTips and tricks for minimal invasive cavity preparation with the Vector system

A characteristic of the Vector system is a resonant ring in the head of the hand-piece. This allows the use of vibration-free instruments in various conventional andasymmetric shapes, each with aerosol eliminated. During the preparation, thesmooth metal instruments are surrounded by a film of water containing the finestabrasive particles. Similar to polishing, the various hard dental tissues and non-metallic restoration materials can thus be prepared without surface or subsurfacedamage. The pulp structures are conserved and the pain response is significantlyreduced. However, the effectiveness of the Vector method arises from the high drivefrequency and the ability to use hollow instruments. Preferable applications are thepreparation of cavities into deciduous teeth, particularly in the case of fearful children,as well as access cavities to initial caries lesions, the excavation of microinvasive cavities for adhesive restoration or the preparation of tooth-colored materials.Furthermore conventionally prepared cavities or stumps could be finished or marginally recontoured advantageously. These short clinical instructions supplementthe clinical manual (Vector: Clinical applications and scientific principles) and givevaluable information on the clinical procedure during Vector preparation.

It is advisable to practice handling the instruments before first use on the patient, e.g. on a suitable extracted tooth.

✔ Silicon carbide slurry (Vector fluid abrasive) as abrasive medium

✔ Preparation in kick-down mode with maximum energy

✔ Instrument held continuously in positioninstead of a wiping preparation movement

✔ Light to moderate application pressure (heavy pressure reduces the abrasive performance); listen for typical erosion noise

✔ Suction of excess liquid in the dorsal oral cavity area; never directly at the preparation site

✔ The maximum erosion rates are achievedusing hollow instruments. These also allowprecise centering of the instrument at thebeginning of a preparation

✔ The desired cavity design is prepared as faras possible by selecting a suitably shapedinstrument (e.g. oval or asymmetric)

✔ High erosion rates are achieved by length-wise sinking of the instruments. Depending oncircumstances, the same or different instrumentsare sunk several times with parallel displace-ment and the resulting interfaces shapedunder horizontal application of the instruments

Check list – Vector preparation

✔ Unilaterally flattened instruments are availablefor proximal cavity segments (half- ellipsoidsor half- flame cones). Care must be taken toavoid damaging adjacent teeth (e.g. matrix band)

✔ Instruments showing signs of wear should beconditioned with the grindstone in the toolkitbefore the next application. Considerably shortened instruments or instruments whoseshape is heavily changed by wear must betaken out of service

✔ The more brittle the material to be worked,the more effective the Vector preparation is.Preparations into enamel are more effectivethan those into dentin

✔ No subsequent finishing of the prepared cavitymargins necessary

✔ With the exception of small amalgam volumes,metals cannot be prepared

✔ Vector is not suitable for removal of dentinalcaries

Left:Functional principle of Vector preparations (schematic)

Right:Instrument conditioning

The burs or sharp edges resultingfrom instrument wear are removedbefore the next preparation. This isdone by operating the instrumentwithout water and recontouring it onthe grindstone in the toolkit.

Preparation principle/handling/instrument conditioning

The Vector preparation uses fine silicon carbide particles (Vector fluid abrasive) with an average grain size of approx. 50 µm suspended in water and washing over the active instru-ments for material removal. By using light to moderate pressureof the activated instrument against the surfaces to be prepared,these particles are accelerated within the operating gap betweenthe instrument and the preparation surface. As a result, the opposite surfaces of instrument and cavity are subjected to erosion. Thereby the tough metal surfaces of the instrumentsabrade only very slowly, whereas effective abrasions occur onenamel, dentine and tooth-colored restoration materials.

A cavity is produced using lengthwise sinking of the instrument as the negative of the instrument shape selected as well as by itshorizontal translation. In contrast to rotating preparation instru-ments, the Vector system produces the highest material removalrates when using longitudinal sinking of the instruments. Whencombined with horizontal preparation movements, the removalrate is reduced. A particularly high rate of material removal andaccurate positioning can be achieved with the hollow instruments.

The abrasion process with loose granules is reminiscent of apolishing process, which explains the very precise, almost athermicand very surface-protecting mode of preparation. As a result of the largely eliminated heat induction of the Vectorinstruments, high cooling water flow rates are not necessary forthe preparation. The application pressure of activated instru-ments corresponds approximately to that of the periodontalapplication of the Vector system. Normally, combined with ahigh erosion effectiveness, there is a typical erosive preparationnoise with which the user soon becomes familiar.

To achieve optimum removal rates, the preparation instrumentsshould be applied continuously in place and only moved to followthe material removal. Heavy application pressures or constantwiping movements familiar from rotating diamonds as well as suction of the liquid surrounding the instrument prevent optimumenergy coupling. For this reason, the very low amounts of excessliquid should preferably be removed by suction sporadically in the area of the dorsal oral cavity on the antagonistic side.

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Advantages

✔ High patient acceptance, reduced pain response (sensitive children, anesthetic often not needed)

✔ Low risk of injury due to accidental slippingof the instrument (nervous children)

✔ Avoidance of structural damage to sensitivecavity margins (marginal seal)

✔ No additional finishing required (time advantage)

✔ Advantageous finishing of conventionally prepared cavity or stump margins (forming instruments)

✔ Protection of soft tissue bordering cavities(reduced tendency to bleeding at gingivalshoulders)

✔ Tissue and pulp protection (caries profunda)

✔ High touch sensitivity (perceptible openingof an initial caries)

✔ Hollow and asymmetrical instruments pre-designed for frequently occurring cavity design (precision)

✔ Low cooling water flow, aerosol eliminated(infected patients)

✔ Beneficial finishing of tooth colored restorations

Limitations

✔ Reduced overview due to suspended particles (release foot switch several timesduring preparation ➔ clear flushing of thepreparation site)

✔ Reduced removal rate compared with rotating diamonds (particularly with horizontal instrument guidance)

✔ Inefficient preparation of large volume cavities or stumps to be provided for prosthodontics

✔ Significant limitations in preparation ofmetal restorations or dentinal caries removal

Vector preparation

Proximal caries (schematic)

Oval access cavity through hori-zontally displaced sinking of a round hollow cylinder (alternative:use of an oval hollow instrument)

• Protection of adjacent teeth• High removal efficiency

Shaping the access cavity

• Mechanical breaking off of theundermined margin

• Overview of the caries extension

Shaping of the access cavity bylengthwise sinking of a hollow cylinder

• Precise centering• High material removal efficiency• Perceptible breaking through into

the carious region

Minimal invasive cavities of Black classes II and III

Hollow instruments in various cylindrical and oval shapes are suitable for the preparation of access cavities for primary carieslesions requiring restoration. The shape of the cavity outline isadvisedly prepared by pre-selection and use of a forming toolwhose own geometry covers the largest possible partial segmentof the cavity to be created. Depending on circumstances, thesame or different instruments are sunk lengthwise several timesnext to one another with horizontal displacement. The resulting

edges at the joins of these cavities can then be removed by lateral movement of the instrument. Unilaterally flattened instru-ments (e.g. semi-spherical, semi-ellipsoid, semi- flame cone) areavailable for proximal cavity segments, in which the risk ofdamage to adjacent teeth is minimized. Furthermore, these instru-ments often allow unusual proximal accesses, for example usinga separating technique or via adjacent cavities. The shaping oftunnel preparations is also made easier.

Caries removal

• Conventional manualinstrument(e.g. with sensitive patients) or round drill

• Successive expansion of theaccess cavity up to the final cavity design with Vector instru-ments and complete display of the carious defect

Preparation of the axial cavity wallsusing micro-semi-ellipse

• Protective processing without marginal fractures; no need foradditional finishing

• Good overview• Minimization of the risk of damage

to adjacent teeth (depending onconditions, additional protectionof the adjacent tooth with metalmatrix band)

Adhesive restoration (separator technique) after acid etching andadhesive impregnation of the enamel and dentin interfaces usingflowable (picture) and/or highly filled composite in a multilayer technique

Class II cavity (schematic) ready foradhesive filling

• Cavity design according to minimal invasive criteria

Preparation of the cervical cavityshoulder using micro-semi flame cone

• Adjacent soft tissue remains uninjured resulting in reduced tendency to bleeding

• Protection of the cervical enamel(where still present)

• Good touch sensitivity• Minimization of the risk of

damage to adjacent teeth (additional metal matrix band if needed)

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Occlusal caries (schematic) Horizontal extension in the fissure relief

• Parallel displaced sinking of circular cavity segments increasesthe effectiveness

• Short preparation pulses alsoincrease patient tolerance

Occlusal access cavity

• Spherical instruments in variablesize gradations allow pinpointaccurate access to the center ofthe carious lesion

Minimal invasive cavities of Black classes I and V

Spherical instruments in variable size gradations, small cylindricalinstruments or an oval hollow instrument are particularly suitablefor microinvasive preparation of Class I and Class V cavities.Particularly with flat, elongated cavities such as are typical, forexample, for opening long fissure sections, horizontal instrumentguidance leads to unavoidable wear of the fine instrument tip. It is advisable in this case to use a parallel displaced sinking ofthe instruments over the desired cavity length, followed by joiningof the individual partial cavities together while creating the final

cavity design. This saves time and reduces instrument wear. The Vector system is of particular advantage in these indicationcategories for deciduous tooth caries (protective preparation particularly of the thin residual dentine layer with efficient enamel abrasion), for pitted caries lesions (adhesive preparationwhile conserving undermined caries-free enamel margins), para-gingival or subgingival cervical defects (protection of soft tissueand reduced tendency to bleeding) as well as for root caries lesions (easy access and protection of soft tissue).

Shaping the definitive cavity designwith horizontal translation of theactive instrument

• Simultaneous beveling of the cavity margins without the needfor finishing instruments

• Maximum hard substance protection

Class I cavity (schematic) ready foradhesive filling

• Cavity shaping according to mini-mal invasive preparation criteria

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Marginal finishing of conventionallyprepared cavities and stumps usingtapered instruments in variable sizegradations (schematic)

Protective recontouring, finishing and polishing of sensitive tooth-colored restorations (schematic)

The indirect energy coupling of the Vector system via the abrasiveslurry minimizes the risk of marginalfractures, particularly in composite fillings and adhesively inserted ceramic restorations. After polymeri-zation of the composite, these aredirectly subject to high volume-inherent residual stresses and aretherefore particularly at risk fromfractures during contouring, finishingand polishing with conventional rotating instruments

Additional applications

Further applications of the Vector preparation device are thefinishing of conventionally prepared cavities or stump margins,finishing tooth-colored restorations or ultrasound-supportedcementing, e.g. using bonding materials on a composite base.

Ultrasound-activated adhesive cementing (schematic)

Using an active Vector instrumentwithout water or slurry on a ceramicor a gold restoration to be cemented,liquefaction of thixotropic bondingmaterial occurs such as, for example,with highly filled composites. Preciserepositioning of the restoration andresidue-free removal of excess cementare thereby made considerably easier.

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Dürr Dental GmbH & Co. KG Höpfigheimer Straße 17 D-74321 Bietigheim-Bissingen

Dürr Dental Online:http://www.duerr.deeMail: info@duerr.de

Author: Dr. Rainer Hahn PhDPrivate Institute for MinimalInvasive Dentistry, Tuebingenhttp://www.zahnerhaltung.comP0

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