Preservation of Root Cementum: A Comparative Evaluation of Power-driven Versus Hand Instruments

Years ago, removal of cementum was standard when performing scaling and root planing. It was believed that the cementum could become “diseased” requiring complete removal as therapy for periodontal disease. However, more recent studies have determined that cementum does not become “diseased”, and removal of cementum is not necessary and can inhibit new attachment. The results of a clinical study published in 2018 in the International Journal of Dental Hygiene aimed to “evaluate how much cementum could be retained as well as the surface characteristics of the retained cementum following in vivo root instrumentation.”¹

This randomized controlled trial compared the results of the root surface and cementum retained after treatment with an ultrasonic instrument with or without air polishing with glycine powder and hand curettage. Twenty-seven patients were included in the study all of whom were diagnosed with severe periodontal disease and scheduled for extraction. Inclusion criteria for participants included systemically healthy, non-smokers, single-rooted teeth or molars with fused roots, > 5mm probing depth in at least two sites per tooth, radiographic bone loss for more than two-thirds of the root length, and bleeding on probing.

The methods included one approximal root surface (distal or mesial) of each tooth that was randomly selected for debridement. The other approximal surface was used as the control. Operators were randomly told which method to use just prior to treatment. All treatment was performed by a single operator.

The results indicated the coronal cementum retained were 84% with ultrasonic scaling, 80% with ultrasonic scaling + air polishing, 94% with air polishing alone, and 65% with hand curettage. “Overall, power-driven instruments were statistically more efficient at retaining cementum when compared to hand instruments.” Additionally, it was determined that single instrumentation procedures were unable to remove all residual calculus deposits, while a combination of instrumentation, ultrasonic scaling and air polishing in this study, removed all residual calculus deposits observed via SEM micrographs.

The authors conclude by giving the clinical relevance of the study. They stated, “Cementum is a key component of periodontal tissue, and its preservation is of paramount importance for the quality of healing at completion of periodontal both non-surgical and surgical treatment modalities. Periodontal reattachment or new attachment as end result of therapy strongly relies on the presence of cementum after root instrumentation. Improper or aggressive mechanical instrumentation may reduce the thickness or eventually remove all the cementum removal in periodontal patients. More specifically, this is the first study to histologically determine, using multiple replicate measures, the effects of a clinician in achieving both debridement and preservation of a diseased root surface on never-instrumented teeth.”

What is your protocol when treating periodontally involved patients? Do you use single instrumentation or multiple? Will the results of this study change your protocol when treating root surfaces? Do you see the value in retaining cementum and its role in reattachment/ new attachment and healing?

Bozbay E, Dominici F, Gokbuget AY, et al. Preservation of root cementum: a comparative evaluation of power-driven versus hand instruments.Int J Dent Hyg. 2018;16(2):202-209. doi:10.1111/idh.12249