Bone Remodeling during Orthodontic Movement of Lower Incisors-Narrative Review.

The tooth movement in the alveolus is possible due to bone remodeling. This process could be the risk factor for the formation of gingival recessions-the most common side effects of orthodontic therapy. Gingival recessions are found 5.8-11.5% more frequently among the orthodontically treated patients. What is more, anterior mandibular teeth are the ones most prone to gingival recession dehiscences and fenestrations. The aim of this narrative review was to evaluate, based on CBCT (Cone beam computed tomography) scans, the changes in the alveolar bone of lower incisors in adolescent and adult patients after orthodontic tooth movements. From the pool of 108 publications, a total of 15 fulfilled the criteria of this review. Both retrospective and prospective longitudinal studies-using CBCT or CT (Computed Topography) and evaluating alveolar bone changes in mandibular incisors during orthodontic treatment performed before and after teeth movement-were included. In the group of growing patients, either proclination or retroclination of mandibular incisors led to increase of the distance from CEJ (cementoenamel junction) to marginal bone crest. The difference in bone loss was greater on the lingual side of the incisors in both types of tooth movement. The results were similar for adults patients. The thickness of the alveolar bone was reduced after proclination (total bone thickness) among growing and non-growing patients and retraction (lingual and buccal) of lower anterior teeth in the group of growing patients. The only improvement was measured for buccal thickness of mandibular incisor in bimaxillary protrusion patients treated with extraction therapy. The control of retraction movement (more root than crown movement) enhanced preservation on bone height and thickness. In order to minimize possible deterioration and place teeth in the center of alveolus, CBCT monitoring and scrupulous clinical evaluation are recommended.

Postorthodontic lower incisor and canine inclination and labial gingival recession in adult patients : A prospective study.

PURPOSE: The goal was to determine whether changes in the inclination of lower incisors and canines upon orthodontic treatment with fixed appliances poses a threat for labial gingival recession in adult patients. METHODS: The sample of this prospective clinical trial consisted of 32 adult patients (mean age 25.08 ±6.50 years) treated with fixed appliances. Plaque and bleeding indices, probing pocket depth, clinical attachment level, gingival recession height (GR) and width (GRW), gingival thickness (GT), and keratinized tissue width were clinically recorded, while cone beam computed tomography (CBCT) was used to evaluate teeth inclination before (T1) and after treatment (T2). Oral hygiene, brushing habits, and smoking were controlled. RESULTS: During orthodontic treatment on 15 (8.33%) teeth (10 incisors and 5 canines), spontaneous complete improvement of pre-existing GR was observed. On 2 incisors, GR decreased and on 3 teeth GR did not change. Moreover, 1 incisor presented an increased GR, while 2 teeth developed new defects. Mean GR, GRW, and GT decreased significantly only on the incisors. Proclination of incisors and canines during treatment (compared with retroclination of the teeth) implicated a lower reduction in GR at T2: 0.19 mm (p = 0.034) and 0.18 mm (p = 0.037), respectively. Multiple regression analysis confirmed that more tooth proclination was associated with a higher risk for an increase in GR (p < 0.00). CONCLUSION: Properly planned changes in lower incisor and canine inclination can be carried out in adult patients without posing a high risk to labial gingival recessions if the individual periodontal biotype is respected. The reported outcomes underscore the orthodontic principle to keep tooth roots inside the alveolar bone.

Relationship between periodontal status of mandibular incisors and selected cephalometric parameters : Preliminary results.

PURPOSE: The aim of this cross-sectional study was to evaluate the correlation between the periodontal tissue of mandibular incisors and several dentoalveolar and skeletal cephalometric parameters. MATERIALS AND METHODS: The sample consisted of 35 patients (mean age 26.42 ± 8.02 years). Eligibility criteria included good overall health status with no history of dental trauma, congenital defects, active periodontal diseases, restorative and prosthetic treatment in the area of the mandibular incisors. Gingival recession width and height (GRW, GRH), gingival thickness (GT), width of keratinized gingiva (WKT) and clinical attachment loss (CAL) were evaluated at 140 lower incisors. Incisors inclination (1-:ML), skeletal class (ANB, WITS), intermaxillary angle (NL:ML) and mandibular symphysis dimensions (symph. length and width) were assessed in cephalograms. Spearman's correlation coefficient was used for statistical analysis at the P < 0.05 level. RESULTS: A statistically significant positive moderate correlation was found for GT and WITS and also symph. length. WKT correlated positively with ANB, WITS and symph. length, with moderate strength of the correlation. GRW, GRH and CAL did not correlate with any cephalometric parameters. CONCLUSION: The results of this study indicated evidence for an association between WKT and GT and some cephalometric variables-ANB, WITS, and symphysis length.