The study included 20 generally healthy adult individuals (10 female and 10 male) aged 19 to 35 with Class I and II malocclusion which a common feature was transverse maxillary deficiency.
A full aesthetic, functional and orthodontic analysis was done prior to the treatment. A periodontal examination was conducted along with photographic and radiographic documentation including orthopanthomogram, cephalometric x-ray as well as cone beam computed tomography. The patients were told about the advantages, disadvantages and risk involved in the corticotomy-assisted orthodontic treatment. All the patients gave their written informed consent for treatment and participation in the study. The study was carried out in accordance with the Helsinki Declaration of 1975, as revised in 2000, and was reviewed and approved by the local ethical committee (Ethics Committee Nr.: R-I-002/344/2011).
Inclusion criteria
Voluntary participation; Legal adult (> 18 years old); Non-smoking; Generally healthy; Malocclusion with transverse maxillary deficiency; Indications for upper arch expansion during treatment; Good oral hygiene and motivation at screening quantified as: FMPI (full mouth plaque index) < 20%, FMBOP (full mouth bleading on probing) < 20%.
Exclusion criteria
Periodontal disease; Oral mucosa lesions; Bisphosphonate and long-term corticosteroid therapy; Current therapy with: anti-epileptic drugs, contraceptives, estrogen, antihistamine drugs, calcitonin, vitamin D; Alcohol and/or drug addiction; Presence of periapical endo-perio lesions; Severe gingival recession; Pregnancy, breast feeding; Previous orthodontic treatment; Previous root resorption; Inability to commit to one-year follow-up.
Surgical procedure
One day prior to the surgery thin arch self-ligating brackets (System Damon, Ormco, Orange, CA, USA) were bonded without placing the archwire. Amoxicillin at a dose of 1 g and ibuprofen at a dose of 200 mg were administered before the surgical procedure. The surgery was done in maxilla under local anesthesia with 4% articaine (Ubistesin forte, 3 M ESPE, USA). The mucoperiosteal flap was elevated up to the point above the apical parts of roots following modified papilla preservation technique as well as performing vertical releasing incisions [23]. Then osteotomy of the buccal cortical plate of the alveolar process was performed by using OTS7, OTS7–4, OTS7-3 ultrasound tips of the piezosurgery device (Mectron s. p. a., Italy). The extension of the osteotomy was determined by the mesio-distal dimension of the teeth roots as well as by the position of the apexes of roots. In order to avoid interproximal bone picks resorption, the vertical cuts ended 5 mm apically from the crest and then Y-shape spread towards the neighboring teeth. The horizontal corticotomy was performed approximately 2–4 mm apically above the root apexes. The depth of the cuts was limited to the thickness of the cortical plate. The repositioned flap was sutured with non-resorbable monofilament 5.0 and 6.0 sutures (Resolon, Resorba Medical GmbH, Germany). Amoxicillin 1 g 2×/day for 7 days, ibuprofen 200 mg 3×/day, mouth rinsing with chlorhexidine (0.10% Eludril, Pierre Fabre Sante, France) 2×/day were prescribed and gentle tooth brushing in the surgical area for two weeks was recommended to the patients. The supragingival plaque was cleaned out 7 and 14 days after the surgery. The sutures were removed 14 days post-op.
Orthodontic treatment
Subsequently after the corticotomy, initial orthodontic wires (0.012 or 0.014 Cooper Ni-Ti) were placed (Ormco, Orange, CA, USA). The follow-ups were performed every 2 weeks for the first three months of treatment, then every 4–6 weeks. The arches were fully leveled and aligned by using increasing sizes of nickel-titanium alloy archwires. The subsequent stages of treatment involved the use of: 0.018 Cooper Ni-Ti wires, replaced with rectangular ones. The therapy was completed with 0.019 × 0.025 steel archwires. The total time of treatment in both jaws took 9 to 12 months. Once the treatment was completed, a permanent retainer was bonded to the lower incisors and canines, while a removable retainer was provided for the upper arch.
Clinical examination
The clinical examination was performed in maxilla prior to the treatment, then 3, 6, 9 and 12 months after the surgery in accordance with the established protocol. The measurements were done using a manual PCP UNC 15 periodontal probe (Hu-Friedy, Chicago, IL, USA) by one calibrated investigator. The total number of examined teeth was 159. The clinical status of the surgical sites was photographically documented during the subsequent appointments.
The following clinical parameters were evaluated: FMPI (full mouth plaque index), FMBOP (full mouth bleading on probing), PD (probing depth), CAL (clinical attachment level), GR (gingival recession height), RW (recession width), PH (papilla height), PW (papilla width), BS (bone sounding), biotype and KT (keratinized tissue).
Clinical parameters were assesed as follows:
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PD (probing depth) and CAL (clinical attachment level) - at six points for each tooth,
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GR (gingival recession, height) - measured at mid-buccal aspect of the tooth from the CEJ to the most apical extension of gingival margin,
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RW (recession width) – mesio-distal dimention of denudated root surface measured at CEJ level,
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PH (papilla height) - measured on the midline of papilla from PW level to the tip of papilla,
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PW (papilla width) - measured at the level of CEJ of adjacent teeth,
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BS (bone sounding) - distance from the gingival margin to the the alveolar crest, measured using a periodontal probe under anesthesia, on the interproximal surfaces of teeth,
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biotype - gingival thickness - measured under anesthesia at mid-facial aspect of the tooth on a long axis 1 mm apicaly fom the bottom of the sulcus with the use of K-file 25 ISO with a silicone marker,
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KT (keratinized tissue) - measured from the most apical point of gingival margin to the mucogingival junction.
All measurements were rounded to the nearest 0.5 mm.
Statistical analysis
All continous variables were tested for normal distribtion by the Kolmogorov–Smirnov test, with Lilliefors corretion and Shapiro-Wilk test. Normal distribution of the quantitative variables was not found. The Friedman ANOVA non-parametric test was used for multiple comparisons to compare more than two related variables. 95% coinfidence intervals were also calculated for differences between baseline and 12 months post-op. Statistical significance was determined at p < 0.05. All calculations were performed using Statistica 10.0 software (StatSoft, USA).