Concepts in periodontal scaling and how tos

1) clock positioning
2) select the correct instrument
3) determine correct working end and side
4) Technique & application

Clock positioning allows for optimum comfort, visibility and access. Patient should be reclined in the dental chair into a near horizontal position.

If you do not get good visual access and adaptation, a good troubleshoot would be to change your chair position. From my experience, this usually resolves the issue. Also, when adapting your instruments onto the tooth surface, you may need to change your chair position simultaneously at times as well.

The diagram above shows the recommended chair position for the respective working field in the patient's mouth. We usually imagine dividing the teeth by the midline when we scale

Anterior teeth - (divide into mesial and distal segments)
Posterior teeth - (divide into buccal and lingual/palatal segments)

So the clock positions for Anterior and Posterior would be as followed:

• Anterior teeth segments that are facing you                                    8-10  O'clock
• Anterior teeth segments that are facing away                                 11-1  O'clock

• Posterior teeth with segments facing you/closer                                9     O'clock
• Posterior teeth with segments facing away                                      10-11 O'clock

Selecting the appropriate instrument is important because you want to be efficient in removing calculus and plaque. And the correct instrument with the most suitable working end and making would allow you to do so.

1) decide if you require sub-gingival or supra-gingival scaling instruments. 

2) check if you have the most suitable shank length for posterior or anterior teeth

3) check the adaptation to determine if you can get the correction angulation whilst having the terminal shank close to parallel with the long axis of the tooth and that your shank and working end is not hugging the whole buccal or lingual surface of the tooth. You want it to be the former.

"adaptation, angulation and application of cutting edge. Repeat with me again. adaptation, angulation and application of cutting edge. Good. Repeat once more"

"adaptation, angulation and application of cutting edge"

These are the 3 concepts for supra-gingival debridement. For Sub-gingival debridement, there are additional steps in addition to these 3 key concepts.

Concept 1: Adaptation

We want to adapt the first 1-2mm of the tip/toe of the instruments to the tooth surface and not the whole face of the instrument

Concept 2: Angulation

Angulation for the sickle scaler should be from 70-80 degrees to the tooth surface. An angulation of 90 degrees would not only be less effective in debridement, it may hurt the patient and cause tissue injury. conversely, <70 degrees will cause burnishing of the calculus which will make further removal more difficult to detect and harder to attain the friction against calculus needed for removal. Angulation for root surface debridement is different! This will be discussed later. 

Concept 3: Application of instrument

For anterior debridement, we use an anterior sickle scaler. We apply one cutting edge to the segments towards the left of the midline and the other cutting edge to the segments towards the right of the midline. Remember to change your chair positioning to get better adaptation. Another thing you can do is to rotate the instruments around it's long axis using your fingers to get better adaptation. 

For posterior sickle scaling, there are 2 different working ends which has 2 different cutting edges. That makes 4 cutting edges in total and each cutting edge has a designated segment of a tooth. Similarly, chair positioning and rotation of instruments will be beneficial. 

Root surface Debridement

For Root surface Debridements, we use curettes. There are a few differences. Can you spot them? 

We first identify the correct working end. 

We do this by lowering the working end to the tooth surface and make a 70-80 degrees face to tooth angle. The terminal shank should be parallel to the long axis of the tooth and not hugging it like on the picture on the right. 

After determining the correct working end, we need to insert the instrument. We want to do this at a 0-40 degrees angulation. This is to prevent tissue damage and maintain the shape of the calculus first because we do not want to smoothen the surface of the calculus as we are inserting the instrument for this will make removal subgingivally even more difficult. Ideally, you want the face of the instrument at 0 degrees to the tooth surface. i.e. Face of the working end hugging the tooth surface.

To summarise this: 1)point the toe of the curette to the gingival margin

2) Position the working end so that the face hugs the tooth surface

3) Insert at ideally 0 degrees angulation into the periodontal pocket

The above picture shows that the insertion of the working end subgingivally. 

Next, you want to angulate once again to get the angulation for calculus removal. Tilt the instrument such that the lower shank is towards the facial surface. 

4) Position the working end under the calculus and 

Tilt the instrument towards the facial surface to establish 70-80 degrees angulation

One thing to note is that you will not see the working end subgingivally.

The solution is to use the angle of the terminal shank to help you gauge this. 

5) Stroke to remove calculus! whilst maintaining 70-80degree! 

Calculus should snap off

 The diagram above summarises the angulations for the different steps required in sub-gingival debridement.

Here's a demonstration by U-Mich on how to utilise a sickle scaler

And this one is on curettes.

HAVE FUN!