Clinical parameters and inflammatory biomarkers among patients with multibracket appliances: a prospective clinical trial.

BACKGROUND: Aim of the presented study was to investigate changes in clinical parameters and active matrix metalloproteinase-8 (aMMP-8) levels in gingival crevicular fluid of patients before and during treatment with multibrackets appliances. METHODS: Fifty-five adolescents scheduled for the treatment were included. Clinical parameters and subgingival samples were obtained at six time points: 1 week before appliance insertion (T0), 3 (T1), 6 (T2) weeks, 3 (T3), 6 (T4) months, and 1 year (T5) after that. Gingival index and plaque index were assessed to evaluated changes on the clinical status. Subgingival samples were collected to analyze changes in aMMP-8. RESULTS: Scores for gingival and plaque index increased after bracket insertion. The gingival index increased from T2 (p < 0.05) until T5 (p < 0.0001). Plaque index also increased, reaching its maximum peak at T3 (p < 0.05). Moreover, an increase of aMMP-8 levels (p < 0.05) was noted. There was no significant between upper and lower jaws. CONCLUSIONS: Treatment with multibracket appliances in adolescents favors dental plaque accumulation and may transitionally increase gingival and plaque index and aMMP-8 levels leading to gingival inflammation, even 1 year after therapy began. TRIAL REGISTRATION: This study was approved by the Ethics Committee of the dental medical association Rheiland-Pfalz, Germany (process no. 837.340.12 (8441-F)), and followed the guidelines of Good Clinical Practices.

Compressive force strengthened the pro-inflammatory effect of zoledronic acid on il-1ß stimulated human periodontal fibroblasts.

OBJECTIVES: The number of patients in dentistry taking bisphosphonates (BP) increases every year. There are only little data about the influence of biomechanical stress due to orthodontic treatment and periodontal inflammation in BP patients. This study focused on the effects of the induced inflammation by IL-1ß in compressed human periodontal ligament fibroblasts (HPdLF) exposed to the nitrogen-containing BP zoledronate in vitro. MATERIALS AND METHODS: HPdLF were incubated with 5 µmol/l zoledronate and 10 ng/ml IL-1ß for 48 h. In the last 3 h, cells were exposed to a compressive, centrifugal force of 34.9 g/cm2. Cell viability was analyzed directly after the compressive force by MTT assay. Gene expression of COX-2 and IL-6 was investigated using quantitative qRT-PCR. PGE-2 and IL-6 protein secretion were measured via ELISA. RESULTS: The cell viability of HPdLF was not affected. Without inflammatory pre-stimulation, COX-2 expression was increased by compression and zoledronate. IL-6 expression was increased under compression. On secretion level, the combination of compression and zoledronate induced a slightly increase of IL-6 secretion. In contrast, inflammatory pre-stimulation strengthened the compressive upregulation of COX-2, as well as induced a higher PGE-2 secretion. Further addition of zoledronate to pre-stimulated cells additionally strengthened the compression-induced upregulation of COX-2 and IL-6 expression as well as protein secretion compared to all other groups. CONCLUSIONS: Biomechanical stress might trigger a pro-inflammatory potential of BP further enhanced in the presence of an inflammatory pre-stimulation. CLINICAL RELEVANCE: To prevent excessive host inflammatory responses, occlusal overloading and mechanical stress due to orthodontic treatment should be avoided in BP patients with untreated periodontitis.

Influence of clodronate and compressive force on IL-1ß-stimulated human periodontal ligament fibroblasts.

OBJECTIVES: The aim of this study was to investigate in vitro the effect of clodronate on interleukin-1ß (IL-1ß)-stimulated human periodontal ligament fibroblasts (HPdLFs) with the focus on inflammatory factors of orthodontic tooth movement with and without compressive force. MATERIALS AND METHODS: HPdLFs were incubated with 5 µM clodronate and 10 ng/mL IL-1ß. After 48 h, cells were exposed to 3 h of compressive force using a centrifuge. The gene expression of cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), matrix metalloproteinase 8 (MMP-8), and the tissue inhibitor of MMP (TIMP-1) was analyzed using RT-PCR. Prostaglandin E2 (PGE-2), IL-6, and TIMP-1 protein syntheses were quantified via ELISA. RESULTS: Compressive force and IL-1ß induced an overexpression of COX-2 gene expression (61.8-fold; p < 0.05 compared with control), diminished by clodronate (41.1-fold; p < 0.05 compared with control). Clodronate slowed down the compression and IL-1ß induced IL-6 gene expression (161-fold vs. 85.6-fold; p < 0.05 compared with control). TNF-α was only slightly affected without statistical significance. Clodronate reduced IL-1ß-stimulated MMP-8 expression with and without compressive force. TIMP-1 on gene and protein level was downregulated in all groups. Analyzing the MMP-8/TIMP-1 ratio, the highest ratio was detected in IL-1ß-stimulated HPdLFs with compressive force (21.2-fold; p < 0.05 compared with control). Clodronate diminished IL-1ß-induced upregulation of MMP-8/TIMP-1 ratio with (11.5-fold; p < 0.05 compared with control) and without (12.5-fold; p < 0.05 compared with control) compressive force. CONCLUSION: Our study demonstrates a slightly anti-inflammatory effect by clodronate under compressive force in vitro. Additionally, the periodontal remodeling presented by the MMP-8/TIMP-1 ratio seems to be diminished by clodronate. CLINICAL RELEVANCE: Reduction of pro-inflammatory factors and reduction of periodontal remodeling might explain reduced orthodontic tooth movement under clodronate intake.

Rapid debonding of polycrystalline ceramic orthodontic brackets with an Er:YAG laser: an in vitro study.

The usefulness of erbium-doped yttrium aluminum garnet laser irradiation for debonding ceramic brackets is assessed using a single laser pulse. Damon Clear brackets were chosen for their 85% transmission of 2.94 µm radiation and were bonded to 20 human third molars using the Blugloo adhesive system. Laser parameters comprised of 600 mJ pulse energy with 800 µs duration, 1.3 mm fiber tip. Light microscopy was used to assess Adhesive Remnant Index (ARI) scores, and scanning electron microscope (SEM) images were taken of the cross-section of the enamel-adhesive interface. Nineteen brackets (95%) were successfully debonded with a single laser pulse, while one bracket (5%) required eight pulses for debonding. For all teeth, the SEM analysis showed no signs of damage to the enamel, and ARI scores of three were observed, supporting the result that the laser effect is confined in the adhesive. The presented laser parameters are able to rapidly debond suitable brackets. The debonding mechanism was concluded to be thermomechanical ablation for single pulse debonding.

Comparison of different plaque indices with regard to sensitivity and specificity for the quantification of plaque during orthodontic therapy.

To compare four plaque indices used in orthodontics. An objective, quantitative plaque index and three subjective conventional plaque indices were analyzed. The study included n = 50 photographs of n = 50 subjects with a multibracket appliance (MB) in the maxilla and mandible. Photographs were taken using Digital Plaque Imaging Analysis (DPIA) and the Percentage Plaque Index (PPI) was calculated. The conventional plaque indices, a modified version of the Turesky-modification of the Quigley & Hein Index (TQH index), Attin index, and modified bonded bracket index (mBB index) were collected from n = 14 evaluators using the DPIA photographs. The evaluators had different levels of orthodontic experience: n = 4 evaluators had little orthodontic experience, n = 5 evaluators had moderate orthodontic experience, and n = 5 evaluators had a lot of orthodontic experience. Plaque accumulation was assessed differently with the plaque indices. Thus, the plaque indices are not interchangeable. We recommend DPIA as an objective, quantitative and sensitive method for plaque determination in scientific studies. The simple statistical evaluation offers a great advantage over conventional plaque indices.