An increasing number of dentists dont use turbines and use instead high-speed-contraangles mounted on a second micromotor.  In my clinic we left with great pleasure the use of turbines about 18 years ago.

High speed contraangle has a mulitiplication of the speed of 5 times. As the micromotor, runs 40.000 rotations pr min (rp/min) the bur of the high speed contraangle runs up to 200.000 rp/min. At the high speed contraangle you use  the same type (friction grip = fg diameter 1,6 mm) of burs and diamonds as in the turbine. (diameter 1,8 mm

What are the advantages of using high-speed contraangles instead of turbines.

a. The high speed contraangle runs faster as the turbine when in use .
As soon as you start to work with it the turbine looses speed, and runs, when under load, often no more than 160.000 rp/min. The high speed contraangle runs independently of the "load"  200.000 rp/min due to electronical stabilization of the speed of the micromotor

b. The torque of the micromotor is much higher than the torque of the turbine.
The torque of the high speed contraangle is so high that you with amalgamcutter a wolfram carbide bur from Komet can cut a old amalgamfilling like a "knife in summerbutter" on very short time.. Only the attention to the pulp, when the tooth is vital , the cooling of the tooth and your manual skill limits the efficiency.  F.ex you can remove old fillings several times faster as by turbine.

c.  Better tactility by the high speed contraangle.
a. The centering of diamonds (and burs) is better by the hign speed contraangle. This improves the tacitlity when working.
b. As the torque of the high speed contraangle is much bigger as by the turbine you can use a higher pressure when you work on the surface of the tooth. This gives you a much better feeling in your hand (tactility) which refines your working reflexes (sensory input to motoric output).
c. If the unitinstruments are balanced so you do'nt need to carry the weight of hose and back part of motor. This too increases your tactility.

d.  Better precision and security by high speed contraangle.
When you need to work with higher precision, you simple reduce the speed of the micromotor.

e.  Both right and left rotation at the minimotor..
A big advantage when working on approximal enamel-edges by ex inlay-preparation and particulary with initial crown preparation.

f.  2 micromotors
If you choos to substitute the turbine with a high speed contraangle 1:5 you will need two micromotors.  One where the ordinary contraangles are used and a second, where the high speed contraangle is mounted. If you place the ordinary contraangle where you often need to change burs and diamonts, -at the left micromoter- you assistant can take over this task.

g.  Important when ordering micromotors for your unit.
Please remember to order micromotor hose with a rotational coupling between hose and micromotoradaptor. This is very important in order to ensure the use of the motor do'nt apply rotational forces at your hand.

4.  MULTIFUNCION-SYRINGE

Most units today are deliverede as standard with Luzzani multifunctional syringes. This syringe has unfortunately very small activation podh-buttons. The movement of these buttons is so short that it not is possible regulate the water for spray. It will either not be activated or activated 100% without intermediate positions. This is NOT practical. Order instead Luzzany multifunctional syringe with LONG LEVERS (the old model). The movement of these levers is so long, that you can regulate spray on 2 - 3 levels. This is needed during our treatments. Heating works in most cases with so much delay, that it never reaches to heat the water before the use of the syringe has finished.

We use in our clinic the syringe with long "buttons" without warm water. For optimal hygiene we cover the syringe with a thin disposable  plastcover. (Disposea-Shield no 3 from Dentsply) This cover is changed between each patient. It is reduced in lenght by a  pair of scissors  and - is fixed at the hose by a small orthodontic elastic. Only the point of the syringe is "outside" the plast-cover. The point of the syringe is sterilized in autoclave and is changed between each patient. The long levers/buttons can easily be activated when covered by the plast.

This procedure is solves the hygienic problems with syringes in a excellent manner and gives a visual indication to  the patient  the hygienic standard of the clinic .We suggest that you have enough points of the syringes to change them between each patient.

 If you place the syringe at left side of the unit, your assistant can use the syringe as well as you can.

5.  ULTRASONIC SCALER can be placed as the únitinstrument most to left side, because the assistant does not need to reach it.

6, SEQUENCE OF UNITINSTRUMENTS   From left side:   Syringe, minimotor with blue contraangle, minimotor with red multiplicationcontraangle, scaler.          A polymerisation lamp may be added at position four between micromotor no 2 and scaler. However is the devellopement of new lamps rapid and it is easier and cheeper to replace a cordless polymerisationlamp.

7. POSITION OF ASPIRATIONTUBES  Aspirationtubes must be placed close to the unitinstruments suspended over the brest of the patients. Distance from syringe about 10 cm. The holder for aspirationtubes may be attached to unitbridge with the unitinstruments, to the chair or to the base of the unit.  It is a big advantage if they additionally can be moved 20 cm forward to left side of the heade of the patient, where they are very easy to grasp for the dentist if (for different reasons) he/she is working solo.

B. PATIENT CHAIR

Patient chair should be comfortable to the patients. Most patient prefer a chair where the leg-support moves down in "sitting position" Take care that the back and headrest not is too long for treating small patients. The headrest should be adjustable in angle and vertical as well. In most cases a manual adjustment of the headreast the most confortable for patients as for dentist (because head of the patients are correctly adjusted)

Cover the headrest with a very soft 3,5 cm pillow of TEMPUR (not the thicker model) for better patietcomfort.

The height of the chair is important.  When you sit in a fine working position, with slight inclining upper legs,  maintained lumbar curvature and without lowering your head,  the mouth of the patient should be in a distance of about 32 cm below your eyes. This may only be a problem if you are taller than about 180 cm, where the chair, with horisontal backreast shout have a max position about 90 cm above the floor. (A number of patient-chair are considerably lower)

There must be place for your legs and for the footcontroller. Many patientchairs have a far too large basis, so the dentist has to sit with widely spread legs and footcontroller at the rigt side of the chair. When working in 9 - 10 o'clock position this is very inconvinient. Chairs with sidelift, offer much place, and a numser of chairs with conventional basis offer place enough. But another number of chairs have much too large a basis.

C.STOOL FOR DENTIST AND ASSISTANT.

The stool must be designed for balanced sitting position, where the dentist sits with inclinated upper legs, an open (110 degrees or more) angle between legs and body, maintaining the lumbal curvature - also when leaning slightly forward in order to look into the mouth of the patient. The support for the ischial tuberosities, the bonestructure which carry our weight, when we are sitting, should be horisintal and well supported to avoid any tendency to glide forwards. This means that softtisue support in the forward part of the midline of the body of male or female to avoid glide forward on seat is unnecessary. This softtissue support is strongly disrecommended because of the disadvantages for male and female users. (male: obstruction of bloodcirculation for penile bloodvessels with risk of impotense, female:risk of infections)

Saddle-seats of different types are fine for the back but are disrecommended as described above, and must be characterized as an anathomical mistake. Furthermore- can wide saddle seats destabilize the hip-joints because of elongation of capsules and ligaments of the joints

D.OPERATION LAMP

The supporting arm of the operation lamp must be so long that the head of the lamp can be placed about 30 cm behind the lying patient, so the direction of the light can be identical as the direction of vision when the dentist is working in 11-12 o'clock position.  Many supporting arms for the lamp are too short, so the dentist cannot work in 12 o'clock position.

The light must have rather, but not too sharp limits and be completely even distribluted in the lightfield. If the ligt has a dimmer the best type ie purely mechanicall, because an eletronic dimmer cause a change in the of light to a warmer colour, which makes a colour evaluation difficult. The colour of the light - colour temparature measured in Kelvin degrees must be high- about 4000 Kelvin approching outdoor light on a day with slight clouds.  LED (light emitting diode) lamps have a very limited colour spectrum and are probably not useful for colour evaluation. This - however needs further research.

E. GENERAL ILLUMINATION OF THE TREATMENT ROOM

The treatment room should have a strong general illumination to reduce the light contrast (which can cause blending) between the mouth of the patient with a illumination of about 22000 lux and the areas in the visual field around the mouth. Best is a illumination of about 1/10 of the operation lamp which is about 2000 lux. The light must be directed downwards but the cieling must too be illuminated in order to reduce light contrasts for the patient. The walls must be illuminated as well with separate lamps, if the standard light does not illuminate the walls. The walls may be illuminated with some differences in lightintensity. An even distribution of light on walls may give a very sleepy apperance, where contrast created by spots can make the room look alive.

F. POSITION OF X-RAY

The absolutely best position of the x-ray is on the wall behind the lying patient. Here the dentist can take the x-ray apparatus with left and and place for exposure on few seconds. A position on the unit is much more complicated.

G.COMPUTER WORKPLACE

It is very useful to have 2 computerworkplaces in the treatment room. One for the assistant and one for the dentist. The assistant can take over writing of diagrammes of different types, writing of the patientcard. The dentist has his workplace where he can make and write treatment plans, an may be diagnoses, description of treatments if the assitant is not yet trained in writing our "professional" language.  Each has a keyboard, mouse and screen.

It is very usefull that the lying patient has a screen placed over his head for looking at x-rayes, intraoral photos, diagrams etc. It must be placed quite precisely, inclined about 45 degrees towards the patient, with the center 45 cm to the front of lower part of headrest of the patientchair with horisontal backrest. The vertical position, is so high up, that the lower part of the screen is above the unitinstrument in highest position used. This allows the arm of the lamp in working position to be placed so the supporting arm of the lamp is above the screen: