Orthodontic treatment for periodontally compromised patients with adjunctive low-level laser therapy : dental and periodontal outcomes

Abstract

In periodontal-orthodontic treatment, patients are compromised in both subjective and objective clinical outcomes. No studies have comprehensively assessed clinical outcomes of periodontally compromised patients in terms of dentine hypersensitivity (DH), periodontal conditions, and orthodontic outcomes over the orthodontic treatment. Low-level laser therapy (LLLT) is a non-invasive treatment modality with promising effects on inflammation control, wound healing, and pain relief. However, there are inadequate investigations on the adoption of LLLT as an adjunct to periodontal-orthodontic treatment throughout the whole active treatment and retention phases. This study was conducted with two aims, namely, to comprehensively investigate clinical outcomes for periodontally compromised patients undergoing orthodontic treatment and to evaluate the effects of LLLT as a novel adjunctive approach to address the clinical challenges of orthodontic retention for periodontally compromised patients, from both subjective and objective aspects, respectively.

To achieve the first aim, we conducted a prospective cohort study to evaluate the DH, periodontal conditions, and orthodontic outcomes of periodontally compromised patients during active treatment and retention. The results showed that the tooth DH in periodontally compromised patients was generally decreased during the orthodontic treatment process. The patients’ periodontal conditions were maintained during treatment and retention. Orthodontic treatment significantly improved tooth alignment and occlusion for patients with a compromised periodontium. The orthodontic indices maintained good stability during retention. The tooth and alveolar bone dimensions were not significantly affected during treatment or retention.

To achieve the second aim, we conducted two systematic reviews to analyse the current evidence for the effects of LLLT on DH management and post-orthodontic outcomes. Based on the information obtained in the reviews, two randomised controlled trials (RCTs) were conducted with a triple-blinded, split-mouth design to investigate the effects of LLLT on DH and post-orthodontic outcomes for periodontally compromised patients undergoing orthodontic treatment. The LLLT group repeatedly received irradiation at 8.6 J/cm2 with a 940 nm diode laser, and the non-LLLT group received pseudo laser treatment following the same treatment schedule as the LLLT group. DH was determined by patients’ subjective ratings on a 100-mm visual analogue scale. Post-orthodontic outcomes were evaluated at multiple follow-up visits based on clinical periodontal parameters; orthodontic indices; tooth and alveolar bone dimensions by radiographic measurements; the bacterial load in dental plaques; and biomarkers of bone turnover in gingival crevicular fluid.

The first RCT showed that LLLT had potential desensitising effects on DH for teeth with a compromised periodontium undergoing orthodontic treatment. The second RCT indicated that LLLT lowered the risk of periodontal inflammation for periodontally compromised patients in the retention stage, by reducing the relative prevalence of Porphyromonas gingivalis in supragingival plaques. However, periodontal parameters, orthodontic indices, CBCT measurements, and biomarkers of bone turnover showed no significant difference between the LLLT and non-LLLT groups for periodontally compromised patients during orthodontic retention.

This thesis describes the first comprehensive evaluation of clinical outcomes of orthodontic treatment in periodontally compromised patients throughout the treatment. Moreover, this study provides the first evidence for LLLT’s potential in DH alleviation and periodontal inflammation control for the periodontally compromised population.