12: Instrumentation

CHAPTER 12 Instrumentation

PURPOSE OF INSTRUMENTATION

The purpose of clinical instrumentation is to create an oral environment where periodontal health is maintained and tissues can return to health. It is accomplished by debridement (or scaling) of the teeth to remove hard deposits to discourage dental biofilm (dental plaque) attachment, such as calculus and/or stain during an oral prophylaxis or nonsurgical periodontal therapy (NSPT), as well as periodontal maintenance (PM). Manual instruments, power-driven instruments, or combination of the two can be used to effectively debride (scale) the teeth and accomplish this goal. Loupes and a headlight are BOTH useful for improving instrumentation. Use of the dental endoscope (Perioscope) creates further opportunity for successful NSPT or PM by offering a tool to aid in definitive instrumentation.

Any instrument that means removal of endotoxins (altered cementum) or by-products of microorganisms from root surface is controversial, and use of other means for removal of dental biofilm is now stressed. Also controversial is the use of traditional root planing with removal of root structure to produce a smooth, glasslike root surface. In addition, soft tissue curettage with removal of the pocket lining is no longer recommended for health of the tissue. Section on polishing in this chapter covers the selective method. Discussion of all these issues is included to allow for changes in testing materials over time. The term “operator” may be used here instead of “clinician” when discussing instrumentation. The Centers for Disease Control and Prevention (CDC) recommends antimicrobial mouthrinse before any instrumentation.

• See CD-ROM for Chapter Terms and WebLinks.

• See Chapter 13, Periodontology: NSPT and PM discussion.

Positioning

The CORRECT positioning of BOTH patient and clinician during instrumentation is critical to long-term comfort and effectiveness of clinician. Takes into account ergonomic principles and incorporation of neutral positioning (see later discussion). Transfer of instruments is not discussed here, except to emphasize that to prevent injury to patient, instruments should never be passed over the patient’s face or eyes. Also not discussed is concept of work zones that are set up like a “clock” around the patient (review from class texts).

• See Chapters 6, General and Oral Pathology, and 16, Special Needs Patient Care: medical diseases and disabilities and additional modifications.

A. Advantages of CORRECT patient positioning:

1. Improves visibility and access to treatment area.

2. Increases treatment efficiency.

3. Increases patient comfort during appointment.

4. Reduces clinician discomfort and fatigue.

5. Reduces possibility of occupational injury such as cumulative trauma disorder (repetitive strain injury) to neck, shoulders, wrist, hand (discussed later).

B. Principles of patient positioning for instrumentation:

1. Basic position using supine position from upright position for initial patient seating:

a. Chair back is almost parallel to floor; parallel to floor for maxillary arch and raised 20° for mandibular arch.

b. Patient is almost parallel to floor; head, heart, and feet are at approximately same height; patient is NOT upright:

(1) Reduces possibility that patient could undergo syncope (fainting), especially during invasive procedures such as local anesthetic administration.

(2) Relative contraindication: congestive heart failure, severe breathing difficulties, advanced pregnancy, back injuries.

2. Patient’s head position:

a. Top of head SHOULD be at top of chair to provide clinician access to the mouth.

b. Head and neck SHOULD be aligned with the spine and supported by chair and headrest.

C. Principles of clinician positioning:

1. Positioning on stool:

a. Feet flat on floor and height adjusted so thighs are parallel to floor.

b. Sit back on stool so that body weight is fully supported and back is against backrest.

c. Keep knees and legs apart to create tripod effect between two feet on floor and stool base to give stable seated position.

d. Arms on a stool allow clinician to rest arms and shoulders between procedures.

2. Ergonomics (good body mechanics): designing tasks and work areas to maximize the efficiency and quality of work.

a. Head SHOULD be centered over spine for support; clinician’s chin is tilted gently downward for visibility, but head is not tilted to right or left.

b. Eyestrain is reduced by having mouth at comfortable focal distance, ∼15 inches from clinician’s eyes to mouth; clinician may need to consider an eye examination and/or loupes if this is NOT comfortable distance.

c. Back is straight without being rigid, tilting forward from hips rather than curling the back or hyperextending neck when necessary to get closer.

d. Keep body weight evenly centered on stool.

e. Shoulders SHOULD be relaxed and even, neither raised toward the ears nor rotated forward (especially if patient is somewhat upright).

f. Upper arm SHOULD be kept close to sides, elbows bent, forearms parallel to the floor.

g. Patient’s chair height is adjusted to place the mouth at level of clinician’s elbows.

h. Wrist is held straight (neutral position) as much as possible; other bending of wrist such as pronounced flexion, extension, or deviation to side SHOULD be avoided to prevent excessive stress on the nerves in wrist area.

i. Hands SHOULD be positioned so that palms are facing inward toward clinician’s midline as much as possible and in same horizontal plane as forearm (neutral position).

j. Assistant SHOULD be at higher level than operator.

CLINICAL STUDY

Scenario: A dental hygienist is on the first day of his new position at a large dental clinic. Before taking this new position, he was the only dental hygienist for over 10 years at the same small dental practice after graduating top of his class at age 20. He notices that he is unable to put his feet on the floor when he sits on the stool provided for him. He also has trouble instrumenting the lower arch; it just seems there is not enough overhead light, especially on the lingual of the anteriors. He also wants to get closer to his patients; he has forgotten what the effective distance to a patient’s mouth is. At the end of the day he notices that his back hurts. He is worried about what this means to his future in his profession.

1. What factors does the dental hygienist need to consider in order to discover why he is having a backache?

2. What could he have done to help with overhead lighting during instrumentation of the mandibular arch, especially the lingual of the anteriors?

3. What is the distance he should have maintained to his patient’s mouths? What can he do if this distance seems too far away?

4. If this situation continues for many years without any changes to his way of practice, what could the outcome be for him?

1. His backache may result from leaning over too close to his patients and not putting his feet flat on the floor with the stool he used. He should be able to sit back on the stool so body weight is fully supported and the back is against backrest. His back should be straight without being rigid, tilting forward from hips rather than curling the back or hyperextending neck when necessary to get closer (see later discussion). In his new employment he needs to locate, request, or adjust a stool that will allow him to practice in a safe and effective ergonomic working position.

2. For treatment of mandibular arch, arch should be approximately parallel to the floor, with overhead light positioned directly over mouth, shining straight down. He may want to see if he can take advantage of more indirect vision and/or illumination with his mirror when he is instrumenting the linguals of the anteriors.

3. He needs to keep himself at comfortable focal distance, ∼15 inches from his eyes to patient’s mouth; may need to consider an eye examination and/or loupes if this is not a comfortable distance.

4. If this continues over time, he could be looking at development of a cumulative trauma disorder, a neuromuscular injury resulting from the accumulation of chronic small traumas to the same area (his back), an occupational hazard for him.

Manual Instruments

Manual (hand) instruments are classified as either assessment or treatment instruments. However, many treatment instruments can also be used for assessment during treatment. Manual instruments include mirrors, explorers, probes, scalers, curets, hoes, files, chisels; available in BOTH basic designs and types and those for specific functions.

Basic Instrument Design

Basic manual instrument design determines the intended purpose and location of use. Specific selections are also based on personal preference and/or ergonomic concerns. Instrumentation with manually activated instruments, BOTH for assessment and for treatment, requires high degree of precision and control and in some cases power and force. CORRECT use of instruments can BEST be accomplished with consistent application of basic principles of instrumentation.

A. Basic instrument design (Figure 12-1):

3. Working end: part that does the work.

a. Curets and scalers (sickle [Jaquette] scalers) are MOST common sharp instruments; cutting edges formed by junction of face and lateral sides.

b. Probes and explorers are MOST common assessment instruments; do NOT have cutting edges; probe tip is dull or blunt, explorer tip is sharp; tip of nonsharp instruments is the “nib.”

c. Mirrors and cotton pliers have special functions and designs.

4. Well-balanced instrument is BEST:

a. Designed with middle of working end centered on long axis of handle.

b. Easier to use, more comfortable to hold, provides better leverage.

B. Manual instrument types: functions and area of use are based on design of working end.

a. Front surface MOST common; reflective coating on face is easily scratched but does NOT produce ghost images.

b. Plane or flat mirrors cause double or ghost images, and concave mirrors magnify images; may cause some distortion.

c. Functions are multiple and may be combined:

(1) Retraction of cheek, lips, or tongue improves access and/or visibility.

(2) Indirect vision: observation of reflected image when direct vision is impaired or impractical; visualization of lingual of mandibular posteriors, distal of maxillary posteriors, etc.

(3) Indirect illumination: provides illumination of dark area by reflected light bounced off mirror face; detection of caries and/or calculus.

(4) Transillumination: light reflected from mirror through tooth to observe shadowing; indication of caries, calculus, pulpal health, especially interproximally.

2. Explorers (Figure 12-2):

a. Thin, wirelike working ends tapered to a point and circular in cross section.

b. Shanks are simple (for hard caries detection) or complex (for hard deposit and root surface exploration).

c. Ends are single or paired (mirror-imaged).

d. Function as providers of tactile information; many need more than one for NSPT:

(1) Assessment of hard deposits (especially calculus) and irregular tooth surface during ALL phases of dental hygiene treatment.

(2) Identification of complex tooth anatomy and pocket characteristics (e.g., concavities, contours of epithelial attachment).

(3) Detection of carious lesions;

assessment of restorations for irregularities, lack of marginal integrity.

e. Basic types:

(1) Shepherd’s hook (#23): hooked single end, BEST for caries detection and restoration evaluation.

(2) Pigtail (or cowhorn): curved shank paired ends, BEST for hard deposit and for exploration of healthy sulcular areas.

(3) The #17: right-angled single end, straight and narrow shank with short 2-mm working end, BETTER for hard deposit and root surface exploration.

(4) The #3A: long curved shank single end, BEST for hard deposit and root surface exploration.

(5) The (ODU) #11/12: area-specific for maxillary molars with paired ends and complex shanks (Gracey-like, others available), BEST for hard deposit and root surface exploration.

3. Probes (periodontal probes): calibrated measuring tool, usually single-ended but can be combined with explorers or other probes on one end; blunt tip (Figure 12-3):

a. Measurements in millimeters; variations in way increments are displayed; color coding with dark or light bands improves ease of reading (some have yellow bands):

(1) Marquis: 3-6-9-12 mm markings; Williams: 1-2-3-5-7-8-9-10 mm markings; Michigan O with 3-6-8, also PCP12 with variable markings on modified Novatech shank, easier to align with vertical tooth axis.

(2) WHO: 0.5-mm ball tip and 3.5-5.5-8.5-11.5 mm markings; used ONLY for periodontal screening and recording (PSR).

(3) Nabor’s (furcation): paired curved design with or without millimeter markings at 3-mm intervals; BEST for identification of furcations and to examine root and/or pocket topography.

(4) Digital (computer): MORE accurate with repeatable measurements, since uses same amount of force and measures to tenth of millimeter.

(5) Laser lightbeam (DIAGNOdent): detects new and residual hard deposits on subgingival areas up to 9 mm with up to 80% accuracy (twice that of conventional probe).

(1) Periodontal assessment:

(a) Measures sulcular and pocket probing depth (PD), distance from gingival margin to epithelial attachment (EA) of the junctional epithelium (JE).

(b) Measures clinical attachment levels (CAL), distance from cementoenamel junction (CEJ) to EA if gingival margin is at or apical to CEJ; distance from gingival margin to EA if gingival margin is coronal to CEJ.

(c) Measures recession, distance from CEJ to gingival margin (when margin is apical to CEJ).

(d) Measures width of attached gingiva, distance from gingival margin to mucogingival junction, minus sulcus or pocket depth.

(e) Assesses gingival characteristics, including bleeding on probing (BoP), with or without indices, presence of suppuration (pus), tissue consistency.

(f) Detects hard deposits and root surface roughness, root and/or pocket topography.

(2) Other uses:

(a) Overjet assessment: distance from maxillary incisal edge to facial of mandibular central; more than 3 mm of overhang.

(b) Overbite assessment: distance of overlap of anteriors in vertical dimension; more than one-third overlap.

(c) Measurement of oral lesions for diagnostic purposes.

5. Curets (Figure 12-5):

a. Lateral sides that taper to form rounded back on working end, with rounded toe.

b. Half-moon shape in cross section.

c. Simple shanks for anteriors and complex for posteriors.

d. Paired, mirror-imaged working ends (matched sets, e.g., #11/12, #13/14).

(1) MOST versatile; BEST for both supragingival and subgingival hard deposits, depending on thickness, length, angulation of shank, working end.

(2) BEST promotion of tissue safety because of rounded toe and back; BEST manual instrument for safe and effective subgingival adaptation.

(3) Controversially: excellent cutting and smoothing abilities for traditional root planing, removal of altered cementum, as well as hard deposits; produces smoothest root surface but removes MOST root structure.

f. Two design types: universal and area specific (Figure 12-6):

(1) Universal curets:

(a) Blade face at 90° to terminal (lower) shank.

(b) Has two parallel cutting edges per working end.

(c) Treat ALL surfaces with just one instrument by use of ALL four cutting edges (two cutting edges per working end and two working ends per curet).

(2) Area-specific curets: Gracey curet MAINLY used (Table 12-1):

(a) Blade face “offset” to 60° to 70° to terminal (lower) shank.

(b) Has one cutting edge per working end (on longer, lower side of blade).

(c) Long shanks and offset angles allow MOST effectiveness in deep, narrower pockets (after fives with about 3 mm longer shanks and also narrower blades; even smaller with micro mini and mini-fives).

(d) Designed to adapt to specific surfaces and teeth; treatment of ALL surfaces of posteriors requires MORE than one instrument.

(3) Turgeon curet: adaptation of Gracey curet with narrower working end and modified triangular blade in cross section that is easier to sharpen.

(4) Langer curets: hybrid of universals with area-specific specifics; long, complex shank design, with blade face that is 90° to lower shank, with two parallel working and cutting edges; must be used in set to access entire dentition, and adaptation is difficult in the posterior with poor access.

(5) O’Hehir area-specific curets: have circular discs at working end with extended lower shank; used with push/pull strokes in deep periodontal pockets and furcations.

6. Hoes (hoe scalers) (Figure 12-7):

a. Bulky working end that gives great strength but makes subgingival access and adaptation difficult; careful adaptation and instrument control are critical to prevent damage.

b. Straight cutting edge with two sharp corners that can gouge a root surface if poorly adapted; straight cutting edge makes adaptation to curved areas difficult; angulation of blade to shank is 99° to 100°.

(1) BEST for removal of heavy supragingival; primarily on lingual of mandibular anteriors and distal of MOST posteriors.

(2) Interproximal removal ONLY if adjacent tooth is missing.

(3) Vertical pull strokes and two-point instrument contact with BOTH cutting edge and shank adapted to tooth for increased control.

(4) Rarely used, replaced by others such as ultrasonics (still used when ultrasonics contraindicated).

8. Chisels (chisel scalers):

a. Straight cutting edge continuous with shank; single or paired ends; blade is flat and beveled at 45°.

b. Use of push stroke (ONLY push instrument EXCEPT for O’Hehir curets).

(1) Best for supragingival use on heavy interproximal; mainly on anteriors; there must NOT be any interdental papilla.

(2) Pushing from facial surface through interproximal surface toward lingual.

(3) Rarely used, replaced by others such as ultrasonics (used when ultrasonics contraindicated).

9. Implant maintenance instruments (see Chapter 13, Periodontology):

a. Made of material that will NOT scratch smooth surface of implants; working ends made of various forms of plastic, graphite, resin, or titanium instruments; ultrasonic tips can use fixed or disposable plastic covers.

b. Shapes vary; some resemble familiar curets and others are uniquely shaped to adapt to round implant shapes.

(1) Removal from surfaces without scratching; very light, lateral force is ALL that is normally needed.

(2) Recommended technique is SIMILAR to curet.

Figure 12-1 Basic instrument design with part noted.

Figure 12-2 Three explorers on left are used primarily for calculus detection; shepherd’s hook on right is used for caries detection or evaluation of restorations.

Figure 12-3 Periodontal probes (from left to right): Nabor’s is curved for furcations, PCP12 with Marquis markings on modified shank, Williams markings at 1-2-3-5-7-8-9-10, Marquis with 3-6-9 markings, WHO with ball tip used to record PSR.

Figure 12-4 Sickle scaler working ends may be either straight or curved. All are triangular in cross section.

Figure 12-5 The basic design of all curets is rounded toe, rounded back, and a half-moon-shaped cross section.

Figure 12-6 Comparison of universal and area-specific curets. Universal curets have a 90° angle between the face and the terminal shank, which gives them two functional cutting edges. Area-specific curets have offset angle with a 70° angle between the face and the terminal shank. This makes lower cutting edge the only one that is used for debridement.

Table 12-1 Gracey area-specific curets

Gracey curet	Designated area of use
Gracey 1-2 and 3-4	Anterior teeth
Gracey 5-6	Anterior or premolar teeth
Gracey 7-8 and 9-10	Posterior teeth buccal and lingual surfaces
Gracey 11-12 and 15-16	Posterior teeth mesial surfaces
Gracey 13-14 and 17-18	Posterior teeth distal surfaces

Figure 12-7 The hoe has a straight cutting edge. Since it is a bulky instrument, used mainly supragingivally.

Figure 12-8 Periodontal file has multiple cutting edges. It is a thin instrument that may be used subgingivally when it fits.

Principles of Manual Instrument Use

Principles of manual instrument use include grasp, fulcrum, adaption, angulation, stroke.

1. Pen grasp: SAME way you would hold a pen when writing, grasping handle with thumb and first finger while middle finger supports instrument from underneath; used with mouth mirror.

2. Modified pen grasp: BEST grasp with manual instruments for BOTH assessment and treatment.

(1) Stable grasp with control.

(2) Allows instrument to be rolled in fingers easily.

c. Used during assessment:

(1) Minimum finger pressure SHOULD be exerted against instrument.

(2) BEST to use light grasp that allows information, especially vibrations, to be sensed by fingertips (e.g., feeling explorer bumping over hard deposit, into furcations, or probe reaching EA).

(3) Pad of middle finger is MOST important in sensing vibrations transmitted up shank.

d. Used during treatment:

(1) Grasp should be light during exploratory strokes made with curets and during placement phase of working stroke.

(2) Grasp should be moderate to firm during activation phase of working stroke.

(3) Close correlation between pressure of grasp and amount of lateral pressure against tooth surface.

B. Fulcrum (finger rest): mechanical leverage point that allows greater force to be exerted at working end without increased effort.

a. Both MORE force and MORE lateral pressure can be exerted.

b. Provides point of stabilization.

c. Allows greater control over instrument and working stroke, MAINLY stroke length.

d. Allows greater patient safety and comfort.

e. Reduces clinician strain and fatigue.

f. Traditional intraoral fulcrum: effective and comfortable for patient in MOST cases: fulcrum finger (ring finger) is placed on tooth surface and remains in contact with middle finger; rocking or pivoting motion is used.

g. Alternative intraoral fulcrums: BEST when used to increase adaptation, improve angulation, or create more effective fulcrum (leverage) location or to create more physiologically sound wrist position: opposite-arch, cross-arch, finger-on-finger.

h. However, when forced to separate fulcrum from instrument grasp fingers (considered split fulcrum), clinician has a loss of stability and strength in working stroke, even with palm-up intraoral rest.

i. Extraoral fulcrums: BEST to increase access and effectiveness by improving adaptation and angulation, especially for posteriors, in small mouths, and in deep pockets of periodontally involved teeth; used MAINLY to increase power and control during working stroke, since whole hand activated:

(1) MUST be at 9 o’clock position and use extended grasp farther down handle.

(2) Palm or back of fingers or hand is rested against the face and reinforced finger rest.

(3) Finger or thumb of noninstrumenting hand is pressed against shank.

(4) Gracey curet’s lower shank MUST be parallel to surface before starting stroke.

(5) Can also be used with ultrasonics.

C. Adaptation: relationship of working end to the tooth surface.

1. Evaluating adaptation:

a. Cutting end SHOULD be positioned so that one third of working end closest to tip is against the tooth (toe third).

b. Point SHOULD be adapted to the tooth as portion of toe third; if point is adapted off of the tooth, can cause soft tissue laceration and discomfort.

c. Heel of working end SHOULD be kept close to the tooth to prevent excessive distention of pocket tissue.

d. SAME guidelines for adaptation are used with both assessment and treatment instruments.

D. Angulation: angle formed between working end and the tooth surface.

1. Assessment instruments (explorers, probes):

a. For caries detection, point of explorer is pressed into tooth surface with terminal portion meeting tooth at 90°.

b. For hard deposit and root surface exploration, working end of explorer is angled about 15° from tooth surface with ONLY toe (terminal) third lightly touching.

c. Periodontal probe is positioned close (almost parallel) to tooth surface with end in contact with the root surface (also considered adaptation).

d. When probing proximal surface where there is adjacent tooth, probe MUST be angled 20° to 30° into col (see Chapter 4, Head, Neck, and Dental Anatomy).

2. Treatment instruments (scalers, curets): angle formed between face of blade and tooth surface (see discussion next on strokes).

a. For insertion into sulcus or pocket: angle is NOT present; as flat against tooth surface as possible.

b. For scaling and working stroke: angle is 70° to 80°; LESSER angle such as <45° results in burnished hard deposits.

c. For curets ONLY:

(1) For root planing stroke: angle becomes MORE closed at 60° to 45° (controversial).

(2) For soft tissue curettage stroke: angle becomes >90° so that cutting edge is directed toward epithelial lining of diseased pocket wall; digitally support tissues (NOT recommended).

E. Stroke: types differ by amount of pressure applied to tooth (lateral pressure) and by length and direction of movement; goal is to cover ALL tooth surfaces.

1. Exploratory stroke: used with ALL instruments for assessment.

a. Grasp and lateral pressure SHOULD remain light throughout, SHOULD be overlapping and multidirectional.

2. Walking strokes: use of up-and-down motion while moving forward around tooth in small steps; used with probes since EA varies in depth and contour.

3. Working stroke (scaling stroke; activation phase): used with treatment instruments.

a. Tight and controlled grasp with moderate to heavy lateral pressure, dictated by hard deposit tenacity; lightest grasp and pressure that will remove deposit is BEST.

b. Overlapping, with various stroke directions.

4. Root planing stroke (controversial):

a. Grasp is moderate to light.

b. Length becomes progressively longer and lateral pressure becomes lighter as root is smoothed (can be followed by root debridement stroke, even lighter pressure to remove dental biofilm on previously planed root).

c. Direction is multidirectional, with cross-hatching.

6. Stroke direction:

a. Selection of stroke direction is based on anatomy of individual tooth, access to tooth and surface, instrument selection, type of hard deposit.

b. Options in stroke direction: vertical, horizontal or circumferential, oblique, cross-hatching (combination vertical, horizontal, oblique).

7. Stroke length:

a. Shorter strokes give more control and used for hard deposit removal.

b. Longer strokes typically used for assessment (exploring and probing) and root planing.

c. SHOULD overlap strokes to ensure that all areas of tooth surface are instrumented.

d. BEST to treat each root as a separate tooth, if access permits, with combination of horizontal, vertical, and oblique strokes.

INSTRUMENT SHARPENING

Manual instruments become dull with use. Sharpening is technique of grinding one or both surfaces that join to form the cutting edge of manual instrument blade until a fine, sharp edge is produced.

1. Preserves original instrument shape, maintains sharp edge, maintains effectiveness of instrument design, extends useful life of instrument, and reduces instrument replacement costs.

2. Increases ease and quality of instrumentation by decreasing hand fatigue and potential for occupational injury.

3. Increases patient comfort because of decreased scaling pressure and reduced number of working strokes needed.

B. Need and frequency of sharpening:

1. ALL instruments with a cutting edge need sharpening on a regular basis:

a. Cutting edge of instrument is formed by junction of face and lateral side; has length but should NOT have width.

b. With use, sharp cutting edge is worn away, becomes rounded and dull, needs to be sharpened.

2. Rate at which instrument becomes dull is determined by:

a. Number of working strokes taken since last sharpening.

b. Amount of lateral pressure used.

c. Nature of the deposit.

d. Composition of metal instrument; carbon steel holds edge longer than stainless steel.

e. When instrument was previously sharpened; sterilization in autoclaves (steam) can dull sharp instruments.

3. Sharpen at FIRST sign of dullness:

a. Amount of work or scaling done since last sharpening; the more working strokes and heavier the deposits, the sooner sharpening is needed.

b. “Feel” of the instrument on the teeth or deposit; dull instruments have LESS grab (slip easily), tend to burnish hard deposits, and have reduced tactile sensitivity during exploring and light scaling.

c. Sharpness test shows instrument to be dull (see assessment discussion below).

d. Instruments may need sharpening periodically during a debridement procedure.

C. Mechanical sharpeners (Sidekick, Periostar): can be used for ease and MOST consistent results, with various stones available.

D. Hand sharpening with stones and lubricants:

1. Arkansas stone: natural stone with fine grit.

a. Lubricated with a fine oil or petroleum jelly before each use to prevent glazing (metal particles clogging pores of stone).

b. May be sterilized by ALL sterilization methods but may become dry and more brittle with repeated exposure to high heat.

2. Ceramic stone: hard, synthetic stone with fine to medium grit (abrasive particle size).

a. Lubricated with water or used dry (useful for maintaining sterile stone).

b. Tolerates ALL sterilization methods.

3. India stone: synthetic stone with medium grit.

a. Recommended lubricants include oil and water to prevent glazing.

b. Can remove large amount of instrument in short amount of time because of increased abrasiveness.

c. Tends to groove and show wear with extended use.

d. Tolerates ALL sterilization methods.

4. Shapes of stones: vary; includes wedge-shaped, cylindrical, conical stones (use on the instrument face).

5. Stone maintenance:

a. Protect the stone and use lubricant matched to the stone type.

b. Use entire surface of stone to prevent grooving.

c. Clean stone before sterilization; remove lubricant and metal particles from stone (glazing) using soap and a brush or ultrasonic bath (if already contaminated).

d. Sterilize stone between patients.

E. Technique: two methods, instrument st/>

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