Principles of Instrumentation Lec 10 General principles for

Principles of Instrumentation ﺍﺳﺘﺎﺫ ﺭﺍﺋﺪ ﻋﺰﻳﺰ. ﺩ Lec. 10

General principles for effective instrumentation are: • Proper position of the patient and the operator • Illumination and retraction for optimal visibility • Sharp instruments 1. 2. 3. 4. grasp finger rest adaptation Angulation Lateral pressure stroke

Positioning of Patient and Operator

• Palatal and incisal (occlusal) surfaces of the max. teeth are viewed in the mouth mirror. • Mand. posterior teeth (on the left side). 9 O'clock • Facial surfaces of the max. and mand. right posterior teeth. • Occlusal surfaces of the mand. right posterior teeth. 12 O'clock lingual surfaces of mand. anterior teeth.

Visibility, Illumination and Retraction

The effective methods for retraction:

Dental light position: For Mand. For Max.

Condition and Sharpness of Instruments all instruments should be : • clean • Sterile • in good condition • The bladed instruments must be sharp to be effective. Sharp instruments enhance tactile sensitivity and allow the clinician to work more precisely and efficiently Dull instruments may lead to incomplete calculus removal and trauma because of the excess force usually applied.

Maintaining a Clean Field The pooling of saliva, blood and debris interferes with visibility during instrumentation and impedes control because a firm finger rest cannot be established on wet, slippery tooth surfaces. Adequate suction is essential and can be achieved with: • saliva ejector • working with an assistant • gauze squares • Compressed air and water.

Instrument Stabilization is the primary requisite for effective instrumentation and avoidance of injury to the patient or clinician. The two factors providing stability are: 1) Instrument Grasp. 2) Finger Rest. A. The palm and thumb grasp is useful for stabilizing instruments during sharpening and for manipulating air and water syringes,

B. Modified pen grasp: The pad of the middle finger rests on the shank. C. Standard pen grasp: The side of the middle finger rests on the shank. tripod effect

2. Finger Rest. serves to stabilize the hand the instrument Finger rests classified as: a. Intraoral finger rests: b. Extraoral fulcrums : 1. Intraoral conventional finger rest: The ring finger rests on the occlusal surfaces of adjacent teeth

2. Intraoral cross-arch finger rest The ring finger rests on the incisal surfaces of teeth on the opposite side of the same arch. 3. Intraoral opposite-arch finger rest The ring finger rests on the mand. teeth while the max. posterior teeth are instrumented.

4. Intraoral finger-on-finger rest: The ring finger rests on the index finger of the nonoperating hand. B. Extraoral fulcrums: are essential for effective instrumentation of some aspects of the max. posterior teeth.

Extraoral fulcrums are : 1. palm-up fulcrum The back surfaces of the fingers rest on the right lateral aspect of the mand. while the max. right posterior teeth are instrumented. 2. palm-down fulcrum The front surfaces of the fingers rest on the left lateral aspect of the mand. while the max. left posterior teeth are instrumented

The reinforcing finger: Both intraoral finger rests and extraoral fulcrums may be reinforced by applying the index finger or thumb of the nonoperating hand to the handle or shank of the instrument for added control and pressure against the tooth. Index finger-reinforced rest. Thumb-reinforced

E. Instrument Activation 1)Adaptation. refers to the manner in which the working end of a periodontal instrument is placed against the surface of a tooth. The objective of adaptation: • to make the working end of the instrument conform to the contour of the tooth surface. • to avoid trauma to the soft tissues and root surfaces. • to ensure maximum effectiveness of instrumentation.

2. Angulation (tooth-blade relationship) refers to the angle between the face of a bladed instrument and the tooth surface. Correct angulation is essential for effective calculus removal Blade angulation. A, 0 degrees: for blade insertion. B, 45 -90 degrees: for SRP. C, Less than 45 degrees: incorrect angulation for SRP. D, More than 90 degrees: incorrect angulation for SRP, correct angulation for gingival curettage.

3. Lateral Pressure. refers to the pressure created when force is applied against the surface of a tooth with the cutting edge of a bladed instrument. Factors affected on amount of Lateral pressure: • • the nature of the calculus. the type of the stroke. Types of Lateral pressure : • • firmly or moderately lateral pressure: is initially applied with removing calculus S stroke. light lateral pressure: is finally applied with smooth the root surface RP stroke.

4. Strokes. The direction, length, pressure and number of strokes are determined by four factors:

Three stroke directions. A, Vertical; B, oblique; C, horizontal. • Vertical and oblique strokes: strokes are used most frequently. • Horizontal strokes: strokes are used selectively on line angles or deep pockets

z i u Q

Ø What are the methods for detection of dental plaque? • What are the Theories of mineralization of calculus? nd (explain the 2 theory )