If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Orthodontic root movement into the alveolar bone consistently reduced gingival recessions.
The recession depth decreased with 23%, the width with 38%, and the recession area with 63%.
All cases improved in Miller's classification from Class III and IV to Class I or II.
The goal of this research was to assess the impact of orthodontic root movement on gingival recessions.
Twelve consecutive adult patients with a mandibular incisor presenting buccal or lingual gingival recession and with the root positioned outside the alveolar bone were enrolled. The roots were moved toward the center of the alveolar process with a goal oriented segmented appliance. The following variables were measured at baseline and after orthodontic treatment: (1) recession depth, (2) recession width, and (3) recession area. In addition, pocket probing depth, keratinized tissue height, and changes in Miller's classification were registered.
The depth, width, and area of the gingival recessions were reduced in all patients without increased pocket probing depth. On average, the recession depth decreased with 23%, the width with 38%, and the recession area with 63% of the baseline value. All patients improved in Miller's classification from Class III and IV to Class I or II.
Orthodontic correction of the root toward the center of the alveolar envelope consistently reduced gingival recessions. The changes in Miller's classification indicated improved prognosis for full root coverage with mucogingival surgery.
Tooth displacement outside the alveolar bone constitutes a risk for the development of a bony dehiscence that may be accompanied by a recession of the gingiva.
However, the association between orthodontic correction of tooth position and “spontaneous” repair of gingival recession has not previously been systematically investigated in a clinical study.
The aim of this study was to quantify the changes of gingival recessions following orthodontic displacement of exposed roots toward the center of the alveolar bony envelope.
Material and methods
Twelve consecutive adult patients (9 females and 3 males), mean age of 28 years and age range 22-41 years, with 1 mandibular incisor presenting either buccal or lingual gingival recession and the root clearly positioned outside the alveolar bone were enrolled for orthodontic root correction before mucogingival surgery. Apart from the gingival recession of the displaced incisor, none of the patients exhibited periodontal inflammation, radiological signs, or clinically detectable defects, which would indicate a past history of periodontitis. Informed consent to participate in the study was obtained. The orthodontic root corrections were performed with a segmented appliance consisting of a torque arch made of 0.019 × 0.025-inch titanium-molybdenum alloy delivering a desired torque equal to the force applied to hook the arch onto the base arch anteriorly to the molar multiplied by the sagittal distance between the displaced tooth and the point of force application. The undesired vertical force was neutralized by a steel base arch resting on the displaced tooth (Fig 1, Fig 2, Fig 3). The base arch also prevented undesired proclination during lingual root torque and undesired retroclination during buccal root torque. As a consequence, only the torque needed for the root movement was expressed, and the center of rotation was at the bracket without side effects on the adjacent teeth. In some patients, finishing corrections were performed with a continuous wire (Fig 3, C). All patients were treated by the same orthodontist. After orthodontic treatment, the patients were referred to the periodontist for mucogingival surgery (Fig 3, D).
At baseline and after orthodontic treatment, the following variables were measured clinically with a calibrated periodontal probe (University of North Carolina-15 probe) and on standardized intraoral photographs: (1) recession depth from the free gingival margin to the cemento-enamel junction, (2) recession width at the cemento–enamel junction, (3) recession area (on photographs), and (4) keratinized tissue height at the midbuccal or midlingual aspect of the exposed root. Furthermore, pocket probing depth was measured using the same calibrated periodontal probe also at the midbuccal or midlingual aspect, and the recessions were classified according to Miller's classification.
The measurements were performed by the referring periodontist and the orthodontist treating the patients. The reported measurements of recession width and depth were made to the nearest 0.25 mm on magnified (factor 10) intraoral photographs of good quality and calibrated to the true value using the clinically assessed widths of maxillary and mandibular incisors as reference. The area of the recession was calculated on the clinical photographs with an open source image processing software (ImageJ, version 2.0.0; National Institutes of Health, Bethesda, MD). Measurements on the photos were repeated after a minimum of 15 days on 12 patients for calculation of the error of the method.
The mean and range of the intraindividual changes in recession depth, width, and area were calculated. Intraexaminer reproducibility was assessed by interclass correlation coefficient. Bland-Altman plots were inspected for the systematic error and the Dahlberg's formula was used for the calculation of the random error. The analysis was performed using Stata software version 14.1 (StataCorp, College Station, Tex).
Excellent reliability was shown when comparing 2 complete sets of measurements with an interclass correlation coefficient ranging from 0.993 to 0.999. Bland-Altman plots revealed no systematic errors for any of the performed measurements of recession depth, width, and area. The random error calculated by the Dahlberg's formula was 0.07 mm for the recession depth and 0.08 mm for recession width and 0.15 mm2 for the area.
The width, depth, and area of the gingival recessions were reduced in all patients. The changes in the individual patients are illustrated graphically (Fig 4, A-C). As a consequence, all patients showed improvement in Miller's classification from Class III and IV to Class I or II. Four patients improved from Miller's Class IV to II, 1 patient from Class IV to I, 6 patients from Class III to II, and 1 patient from Class III to I. On average, the recession depth decreased with 23% (range 4.35%-43.75%), the recession width with 38% (range 27%-67%) and the recession area with 63% (range 36%-93%) of the baseline value. In 2 patients (Fig 4, A, series 9 and 11) the depth was reduced with <10%, but the overall reduction in width lead to more than 50% reduction in recession area in these 2 patients. The height of the keratinized tissue was at baseline ≤1 mm in all patients. After orthodontic treatment, 7 patients did not show a measurable increase in the height of keratinized tissue and 5 patients demonstrated an increase of ≤0.75 mm, although not corresponding to the amount of reduction in recession depth in any case. Pocket probing depth was unchanged with measurements ≤1 mm in all patients both before and after orthodontic treatment.
Gingival recessions of mandibular incisors may be related to displacement of the root outside the boundary of the alveolar envelope. This report evaluates the effect of orthodontic repositioning on the extension of the gingival recession.
The appliance used generated a large torque moment with small forces omitting side effects on the adjacent teeth because these were not included in the appliance during the correction. The vertical forces acting on the molars were of a magnitude that was neutralized by occlusal forces.
After orthodontic treatment, all patients had improvement of the recession depth, width, and area leading to an improved Miller's classification. However, the depth was reduced <10% in 2 patients. This may be explained by a thick lip frenulum attaching close to the recession in these patients. Reduction in the width nevertheless resulted in a reduced recession area also in these patients. The recession width was measured at the cemento-enamel junction, but the width decreased in the entire extension of the recessions and often more in the apical part of the recession, which is also seen in Figures 1, A-E and 3, A-C.
The reduction of recessions following root movement toward the center of the alveolar process confirmed the findings of previous animal studies
For ethical reasons, regeneration of the marginal bone level could not be assessed in this study, but an improvement was observed by the periodontist in 1 patient, where a periodontal flap was raised both before and after the orthodontic root correction. This finding is supported by the findings of animal studies
where the correction of a root displaced out of the alveolar housing resulted in the regeneration of bone. A cone beam computed tomography (CBCT) evaluation of changes in the marginal bone level was not performed because the thickness of the alveolar bone plate could be expected to be below the imaging spatial resolution of the CBCT scanning. Therefore, a CBCT evaluation would expectably lead to false findings
the Class III defects have the gingival margin located at or beyond the mucogingival junction with interproximal bone loss and/or tooth malpositioning. The Miller Class IV defects are defined by serious interproximal bone loss and/or severe tooth malpositioning.
be treated to complete root coverage by mucogingival surgery. However, Class I and II recessions can be fully covered with mucogingival surgery. In this study, the recessions classified as Miller Class III and IV because of tooth malposition beyond the bony alveolar housing. The orthodontic treatment directed the roots to the center of the alveolar process and converted the Miller classification of the recessions to Class I or II, and thus a more favorable starting point for periodontal plastic surgery.
All cases in the present study exhibited a “spontaneous” improvement of the connective tissue coverage, and some patients might not even need surgical intervention following orthodontic correction with “spontaneous” repair of the recession. However, the reduction in recession depth did not result in increased height of the keratinized tissue in most patients, which can be related to a modest reduction in recessions depth. The pocket probing depth was ≤1 mm both before and after orthodontic treatment, which possibly can suggest that the periodontal ligament migrates coronally leading to an improvement of the clinical attachment level.
The results demonstrate the potential synergy of an interdisciplinary orthodontic and periodontal treatment of patients with gingival recessions related to roots positioned outside the alveolar bony housing. Moving the roots first to an ideal position within the alveolar process can reduce the recession and improve the prognosis for following mucogingival surgical intervention. The measurements of recession dimensions were performed on magnified intraoral photos. A possible limitation of this method could be the orientation of the photos. However, the photos were standardized, and the applied method has been evaluated in a previous study
demonstrating that measurements of gingival recessions are reliable on clinical photographs. Clinical measurements of recession dimensions are not reported because there was no assessment of repeatability and reproducibility for those, but the clinical measurements in the sample generally reflected the measurements performed on photographs. If clinical measurements of recessions should be considered the “gold standard,” indeed, the validity and reproducibility of using photographs and ImageJ to evaluate the percentage of root coverage have been assessed by Kerner et al,
who found the method highly correlated with clinical measurements. The sample size was limited owing to the inclusion criteria, and only mandibular incisors were investigated in the current study. Presumably, the results can be applied to other tooth types as reported by other authors.
Applicability of the findings can be discussed since baseline recession dimension and incisors displacement varied, and individuals tend to have different responses to the same treatment. Nevertheless, the reaction shared by all patients was a reduction of the recession width, depth, and area following orthodontic movement of the root toward the center of the alveolar process. The amount of orthodontic displacement into the alveolar process can sometimes be limited by the buccolingual thickness of the alveolar process, and care should then be taken not to displace the root out of the bone on the opposite side of the recession.
The findings of this study indicate that orthodontic correction of roots positioned outside the alveolar process has important clinical impact. The obtained root position within the alveolar process was followed by reduced gingival recessions in all patients and provided a more favorable surgical site for a periodontal plastic surgery to fully cover the recession.
Bone regeneration in orthodontically produced alveolar bone dehiscences.
We congratulate the authors for their notable work in the area of orthodontic force application, gingival recession, and its repair, which is one of the untouched aspects of the interdisciplinary approach.1 The research question of the study was clear in producing a better clinical impact. The following are concerns that, if clarified, might improve the clinical approach and outcome: