1. Applying principles of 4-handed dentistry in daily practice

2. Dimensions of four-handed dentistry The original intent of four-handed dentistry was to increase the productivity of the dentist while minimizing the stress and fatigue associated with practicing dentistry

3. Point 1: principles of work simplification Dentistry is a demanding profession that requires precise skills involving : - a large armamentarium of instruments and materials - effective management of patients and human resources - efficient coordination of the activities of dental team

4. 4 components that govern work simplification 1. eliminate 2.combine 3.rearrange 4.simplify

5. 1. Eliminate In analyzing the individual steps in any given procedure, it is often possible to reduce the number of instruments, equipment and movements used to accomplish a particular task. Example: -reduction of instruments for amalgam application (eliminating a number of instrument transfer) Benefits: - longer time for patient treatment - shorter time of daily activities for dental team

6. 2. Combine When the functions performed by two instruments or two pieces of equipment can be incorporated into one instrument or one piece of equipment - double-ended instruments (reduce the number of instr. To be purchased and sterilized and transferred) - rubber-dam (pre-prepared and combining all steps of application into one outside the mouth: clamp, rubber dam and frame) - reduction of cotton pellets for mouth

7. 3.Rearrange 4.Simplify Work environment should be adapted to the needs of the dental team - easy displacement of dental cabinet - open drawers on gaze level - closed drawers for other equipment placed on lower shelves (you can see it from up top) - distance between mouth, equipment and dentist’s hands

8. Concepts of motion economy Class I – motions involving fingers only Class II – motions involving fingers and wrist Class III – motions: fingers, wrist, elbow Class IV – motions involving the entire arm (shoulder included) Class V – motions involving the arm and twisting of the body

9. We should minimize the number of Class IV and V movements in the chairside work When performing Class IV and Class V movements, we observe two phenomena: - the operator tends to lose the required visual concentation - lower light intensity in the operating field

10. Functional Operating Position In order to achieve a ‘’functional” position we will provide: - access to the operating field - good visibility - comfort for the dental team and patient

11. ‘’Functional operating position” : 1. Placing the patient in supine position 2. Use of a dental mirror (mirror view of upper teeth, direct view of lower teeth) 1. Use of high speed evacuation 2. Effective instrument transfer 3. Proper positioning of equipment and materials

12. General guidelines for the proper position for dentist and dental assistant 1. The back and neck should be kept relatively erect 2. The shoulders should be maintened parallel to the floor 3. The upper body should be fully supported by sititing completely on the seat of the stool 4. The upper arms and elbows should be kept close to the upper body 5. The forearms are maintened parallel to the floor. 6.The thighs are maintened parallel to the floor by proper adjustment of stool height 7. For the dentist, use of a properly adjusted backrest will give additional support to the back.

13. General guidelines for the proper position of dentist and dental assistant 8. For the assistant, the support arm is adjusted to support the upper body just below the rib cage, and/or used as a rest for supporting the forearms and elbows 9.For the dentists, feet should be kept flat on the floor. 10. For the assistant, feet should rest flat on the stool footrest Frequent deviations from this posture may cause strain and fatigue, and over a long period of time may produce impairment of body. If you must lean forward, do so by engaging your hips rather than neck and shoulders

15. Seating and positioning the patient Remember, the patient is in the chair for a short time, whereas the dental team is at the chair all day. 1. Raise the arm rest 2. Position the chair seat at a comfortable level. 3. Lower the backrest approx. 30 degrees from the upright position 4. After the patient is seated, raise the chair sufficiently to allow the dentist’s legs under the backrest when it is lowered 5. Tilt the seat back until the patient’s calves are parallel to the floor. 6. Slowly lower the chair back until: - The maxillary arch is in a plane perpendicular to the floor - A line from the patient’s nose to knees is parallel with the floor 7. Ask or assist the patient to move his head to the top of the chair and all body toward the dentist. This reduces the need for the dentist to bend or reach in order to gain adequate access or visibility 8. The patient’s mouth should be now at elbow level for the dentist and the dentist should be able to maintain his forearms parallel to the floor

18. Access to some areas of the mandibular arch require a modification in the supine position. By lowering the chair seat and raising the backrest until the mandibular arch is approximately parallel to the floor will allow improved access and visibility to the posterior mandibular areas.

19. 4 zones of activity DENTIST’S ZONE DENTIST’S ZONE 8-12 o’clock for right- handed dentist 12-4 o’clock for left handed- dentist STATIC ZONE Instrumentarium 12-2 o’clock for right- handed dentist 10-12 o’clock for left-handed dentist

20. ASSISTANT’S ZONE it allows the assistant to sit in direct line with the operating field in a 3 o’clock position, with her legs parallel to the dental chair backrest, it is in this zone that the assistant’s mobile cabinet is located, allowing immediate and easy access to used instruments 2-5 o’clock for right-handed dentists 7-10 o’clock for left-handed dentists

21. TRANSFER ZONE the greatest shared activity of dental team, instruments transfer at or below the patient’s mouth 5-8 o’clock for right-handed dentist 4-7 o’clock for left-handed dentist

22. Any interference with the primary function of each zone must be avoided. Example: movement of the dentist to the static zone will require the assistant to position herself away from the operating field, resulting in reduced access and visibility and increasing the number of Class IV and V motions

23. General precautions on patient care 1. When placing the patient in the supine position or returning the patient to the upright position, always lower and raise the backrest slowly so as not to induce dizziness 2. Be certain that medical history is free from contraindications to place patient in a supine position 3. Remove any dental prostheses and wrap them in a moist environment 4. Patients who wear eye glasses should be asked to take them off, as debris is sometimes splashed onto the face as a result of the ultra speed handpiece. Patients who do not wear glasses should be provided with a pair of plastic safety glasses or ask to close their eyes during cutting procedures. Dentists and assistant should wear eye glasses when working. Bacterial splash is a constant hazard for dental personnel. 5. To prevent patient from swallowing or aspirating any foreign bodies, use a rubber dam. Proper evacuation and careful working procedure will do much to reduce this potential hazard 6. Place a cushioned inset under the patient’s neck or small lump of the back. It is usually done when a short patient is moved to the top of the chair and loses a lumbar support provided by the chair contour.

26. Oral Evacuation The primary goals of high volume evacuation: 1. Prevent rapid accumulation of debris and fluids in the patient’s mouth 2. To insure a clear operating field There are 2 types of the evacuator tip: P – is used for posterior areas P – is used for posterior areas A – is used for anterior areas

28. 2 methods of achieving control with the evacuation tip: a. pen grasp b. thumb to nose when assisting a right-handed dentist the evacuator tip is held in the assistant's right hand. The opposite is true when assisting a left-handed dentist. Stability and control is achieved when the assistant’s right arm is kept as close to her body as possible. The assistant’s left hand must be kept free for retraction, manipulation the three-way syringe and instrument transfers.

29. Tissue retraction-to prevent bruising of the oral mucosa 1. In buccal surfaces, placement of cotton rolls in the buccal fold or sulcus will protect tissue 2. In the posterior mandibular lingual area, the assistant must retract the tongue and prevent damage to the tissues of the floor of the mouth. Cotton rolls can be placed between tongue and mandibular arch. 3. In case of an extremely muscular and active tongue the assistant can retract it with mirror or tongue blade held in the left hand ( in the right hand-evacuator tip) 4. In the maxillary arch or posterior mandibular areas, dental assistant must avoid compressing the lower lip !

30. Placement of the evacuator tip 1. Select the appropriate end P or A 2. Select that grasp which permits the greatest control and maximum retraction of tissues 3. Activate the vacuum to its most open position 4. Place cotton rolls and/or retraction devices 5. Place the evacuator prior to the movement the dentist places handpieces in the oral cavity. This is nonverbal signal that the assistant is ready. That also minimizes blocking the dentist’s view. 6. Place the bevel of the tip parallel to and slightly distal to the tooth being treated. 7. Place the tip beyond the occlusal or incisal surface of the tooth. 8. As necessary, move the tip to the lowest point in the patient’s mouth to evacuate accumulate fluids. If access prevents placement of the tip as described, evacuate in the lowest and most posterior position of the mouth. Most of the fluid will accumulate there.

31. the assistant keeps the air-water syringe in the left hand and utilizes it for - periodic rinsing of the operative field: - keeping the mirror surface clean when it is in use The dentist only needs to turn the mirror away from the patient’s mouth. This serves a nonverbal signal to the assistant

32. Instrument handling and transfers Trays can be color-coded to indicate their particular use. blue- can indicate an amalgam procedure red- composite procedure yellow- gold, a crown and bridge procedure

33. One method is to place a stripe of color- coding tape on the edge of the tray and stripes of the same colored tape on all the instruments included on this tray Some practical suggestions governing the use of pre-prepared trays are as follows:

34. 1.Include only those instruments and supplies routinely used in a given procedure 2. Arrange the instruments from the left to right in the sequence of their use 3. After an instrument is used, return it to its proper location on the tray 4. Place the tray on the mobile cabinet such that instrument transfers can be accomplished without resorting to Class IV and Class V movements. 5. Additional items used during a procedure can be stored in the mobile cabinet and/or in fixed cabinetry or on counter- tops within the operatory

35. Basic instrument grasps 1.PEN GRASP 2.REVERSE PEN GRASP 3. PALM GRASP 4. PALM-THUMB GRASP

37. 1. All instruments transfers occur at or just below the level of patient’s mouth. 2. Instrument transfers are never made over the patient’s face where a slipped instrument could result in serious injury to the patient. When transferred, instruments should have their working ends pointing in the direction of use. 3. All transfers are carried out with the assistant’s left hand. The right hand must be free for evacuation, retraction, or use of the air-water syringe. 4. The assistant lifts desired instrument from tray by grasping it with the thumb and first 2 fingers: II+III and shank at the opposite end of that used by the dentist 5. The instrument is then held parallel to the instrument currently being held by the dentist, with the working end pointing in the direction of anticipated use. 6.. 7. Instrumenty przenoszone są równolegle do zestawu w kierunku ręki lekarza. 8. W idealnym układzie asysta wyprzedza działania lekarza i dokonuje wyboru następnego instrumentu.

39. 6. When the dentist indicates that he or she is ready to exchange instruments, the assistant grasps the used instrument at the non-working end with her or his last two fingers (ring finger and pinkie) (the nonverbal signal can occur when the dentist lifts the working end of the instrument from the tooth) 7. The assistant immediately tucks the retrieved instrument back into the palm and in the same movement places the new instrument into the dentist’s hand in the position in which it will be used

40. At no time during the transfer process it is necessary for the dentist to lose the finger rest or take his/her eyes off the operative field.

41. SYRINGE TRANSFER 1. To distract the patient’s attention from the syringe by appropriate casual conversation 2. While the dentist is applying topical anesthetic with his or her right hand, the fingers of the left hand serve as a screen to the patient’s vision 3. The assistant holds the syringe by the barrel to the left of the patient’s head and below the patient’s line of vision.

44. The dentist removes the topical anesthetic applicator, which is retrieved by the assistant’s left hand. The dentist right hand is placed beneath the outstretched syringe. The assistant places the thumb ring over the dentist’s thumb and removes the needle cover

46. Light For mandibular teeth light must be placed slightly behind patient’s head For maxillar teeth light must be placed above patient’s head There is one governing rule: the angle between line of dentis’t sight falling on the operating field and central ray of lamp should be the smallest as possible Placement of the lamp changes constantly during 1 dental procedure.

47. Summary The main objective of 4 handed dentistry is to provide a maximally efficient and effective work environment. Eliminate, combine, rearrange and simplify are the central components of work simplification. To analyze chairside activity there are I, II, III, IV, V classes of motions Functional operating position provides access and visibility to the work are Proper patient positioning will enhance this access.

48. Summary Mastery of oral evacuation technique prevents accumulation of debris and fluid. Proper retraction and use of three-way syringe will enhance visibility and access Correct instrument handling and transfer must be well-coordinated between dentist and assistant.