Preservation of root cementum: A comparative evaluation of power-driven versus hand instruments

Recent studies have reported that endotoxins were not located within cementum and removal of ‘diseased’ cementum was not necessary for a successful periodontal treatment.  Saygin et al concluded that preservation of cementum on the root surface was necessary for new attachment and as a source of growth factor. Hence non-aggressive removal of cementum is essential for optimal periodontal health and regeneration.

Ultrasonics with new shaped tips and subgingival air polishing devices has been developed for removal of root accretions with minimal root damage. Air polishing has been suggested as a treatment modality for root debridement resulting in probing depth reductions and removal of subgingival biofilm. No scientific evidence exists today showing the loss of root substance or surface roughness produced by either ultrasonics or Air polishing. 

Aim
To assess the amount of cementum remaining following in vivo root instrumentation as well as the surface characteristics of the retained cementum 

Material and Methods

- 48 caries free, single-rooted teeth in 27 patients diagnosed with severe chronic periodontitis with periodontal probing depth (PPD) ≥5 mm in at least two sites per tooth with radiographical bone loss of more than two thirds of root length and scheduled for extraction were included in this study

- Teeth were randomly divided into four treatment groups: Instrumentations were performed with medium power settings 

1. Piezoelectric ultrasonic scaler - (Air-Flow Master Piezon, Instrument Tip PS; EMS SA)-U

2. Piezoelectric ultrasonic scaler - (Air-Flow Master Piezon, Instrument Tip PS; EMS SA) followed by air polishing with the glycine powder (Air-Flow Powder Perio, Perio-Flow Nozzles; EMS SA) - U + AP

3. Air polishing with the glycine powder (Air-Flow Powder Perio, Perio-Flow Nozzles; EMS SA) - AP; 

4. Hand instruments (Gracey curettes 5/6, 11/12, 13/14 American Eagle, Missoula, MT, USA)-HC

Treatment

- One approximal root surface of each tooth was randomly subjected to debridement, and the other approximal surface was used as control.

- Following instrumentation, the teeth were immediately extracted traumatically and analyzed with a dissecting microscope 

- Remaining calculus, root surface roughness and loss of root substance were evaluated along with scratches, gouges, cracks, and any other changes in the cementum that was present were noted.

Results
Remained cementum:

- Percentage of coronal cementum remaining following subgingival instrumentation was 84% for U, 80% for U + AP, 94% for AP and 65% for HC. 

- The amount of retained cementum with AP was significantly greater than with HC. SEM 

- Smoothest root surfaces were produced by the HC followed by the AP

- Coronal and apical sections showed that AP produced the least amount of cementum loss and therefore the greatest retention of residual cementum

- Root surfaces instrumented by U or U + AP presented grooves and scratches.

Time taken to complete root instrumentation

- Shortest time taken was using AP and the longest time was with U + AP.

- AP required 31% less time for root preparation in comparison to HC, whereas U + AP needed 30% more time 

Conclusions

- Air polishing was significantly more effective and superior in preserving cementum.

- Hand instrumentation using curettes was most effective in removing cementum in comparison to ultrasonics or hand instruments

Editorial Note: The article was originally published in International Journal of Dental Hygiene. 08 September 2016, page 1-8