Bone-anchored maxillary protraction in patients with unilateral complete cleft lip and palate and Class III malocclusion

Clinical Oral Investigations https://doi.org/10.1007/s00784-018-2627-3 ORIGINAL ARTICLE Bone-anchored maxillary protraction in patients with unilateral complete cleft lip and palate and Class III malocclusion Yijin Ren 1 & Ralph Steegman 2 & Arjan Dieters 2 & Johan Jansma 3 & Harry Stamatakis 2 Received: 7 March 2018 / Accepted: 10 September 2018 # The Author(s) 2018 Abstract Objective This prospective controlled study evaluated the effect of bone-anchored maxillary protraction therapy in cleft children with Class III malocclusion using CBCT-derived 3D surface models. Materials and subjects Eighteen cleft patients between 10 and 12 years old were included. Intermaxillary elastics were worn after the placement of four zygoma bone plates for 18 months. Uniquely, three age-matched untreated groups including both cleft subjects and non-cleft subjects with Class III malocclusion served as controls. Profile photos and CBCT scans for each patient were taken before (T0) and 18 months after the protraction (T1). 3D measurements were made on CBCT surface models from the treatment group using tomographic color mapping method. Cephalometric measurements were made on lateral cephalogram reconstructed from the CBCT scans and were compared with those obtained from the control groups. Results Two thirds of the treatment subjects showed improved lip projection towards more convex facial profile. The most significant skeletal changes on 3D surface models were observed at the zygomatic regions (mean 1.5-mm forward, downward, and outward displacement) and at the maxillary complex (mean 1.5-mm forward displacement). Compared with the control groups, the treatment subjects showed significant increase in the SNA and ANB angles, increased Wits appraisal, a more forward movement of point A and overjet improvement (p < 0.05). Conclusions BAMP in cleft patients gives a significant forward displacement of the zygomaxillairy complex in favor of the Class III treatment. Clinical relevance This treatment method shows clearly favorable outcome in cleft patients after 1.5 years of BAMP. Keywords CBCT . Bone anchored . Maxillofacial protraction . Color mapping . Superimposition . Cleft . Orthodontics . Class III malocclusion Introduction Class III malocclusion is a common anomaly in children with cleft lip and or palate mainly due to maxillary deficiency. Conventionally, growing subjects with maxillary deficiency were treated with a facemask (FM) with a heavy anterior * Yijin Ren 1 Department of Orthodontics, W.J. Kolff Institute, University Medical Center Groningen, University of Groningen, BB72 300001, Hanzeplein 1, 9700RB Groningen, The Netherlands 2 Department of Orthodontics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands 3 Department of Oral Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands traction applied on the maxilla to stimulate its forward and downward movement and to restrain and redirect mandibular growth. There is some evidence showing more favorable results with facemask therapy on early age [1, 2]. However, the best treatment timing and duration for facemask therapy remains controversial, and the skeletal and dental changes were adequately tested only in the short term. Long-term results and stability of this treatment modality remain debatable [3, 4]. Moreover, undesirable treatment outcomes of face mask have been reported such as dental compensations as a consequence of the application of forces on the teeth and an increased facial vertical dimension as a result of posterior rotation of the mandible. Additionally, facemask wear heavily relies on patient compliance and is usually limited to 12–14 h/day due to the social barrier [1, 5, 6]. The addition of rapid maxillary expansion (RME) showed enhanced effect of the FM therapy. Less dental compensations are demonstrated when a facemask used in combination with a Hybrid Hyrax, a rapid palatal expansion Clin Oral Invest appliance which is both tooth- and bone-borne. [7]. Protocols of maxillary expansion and protraction, such as the Alternate Rapid maxillary Expansions and Constrictions protocol(AltRAMEC), proposed by Liou et al., showed favorable skeletal results up to 17 to 21 years of age in some patient, but with evident dental compensation [8, 9]. In recent years, titanium miniplates used for anchorage has been advocated as an alternative treatment modality to apply bone-borne orthopedic forces between the maxilla and the mandible, therewith minimizing dentoalveolar compensations [10, 11]. Compared with treatment with facemask in combination with rapid maxillary expansion, bone-anchored maxillary protraction produced 2- to 3-mm larger maxillary advancement with similar mandibular sagittal changes, better vertical control, and a lack of posterior rotation of the mandible demonstrated by both 3D CBCT images and 2D cephalograms [12, 13]. Compared with untreated non-cleft subjects with Class III malocclusions, bone-anchored protraction induced an average increment of 4 mm on maxillary advancement and favorable mandibular changes exceeding 2 mm based on cephalometric analyses [14]. Though anchored maxillary protraction has showed favorable results in non-cleft growing subjects, no previous study has investigated the effect of this treatment modality on maxillofacial complex in cleft patients until very recently [15]. In that study, Yatabe et al. (2017) compared a group of Brazilian cleft patients with a group of Belgian non-cleft subjects on CBCT models and reported comparable efficacy in maxillary displacement in the two groups. Till date, no studies have compared the outcome of boneanchored protraction therapy in cleft patients with that in untreated Class III non-cleft patients or Class I or II cleft subjects, nor have any studies investigated the lip projection changes on facial profiles. Growth trends are intrinsically different in different facial types and skeletal anomalies [16]. Facial growth in cleft children showed different patterns from non-cleft subjects with similar malocclusions [17]. In the development of Class III malocclusion, non-cleft and cleft subjects bear different etiologies [18, 19]. These observations point out the importance of including both non-cleft and cleft subjects as controls in order to illustrate the treatment outcome of a specific intervention. Comparisons only with non-cleft subjects undergoing the same therapy or with untreated non-cleft subjects may obscure the actual craniofacial response of cleft subjects to an intended therapy. Therefore, the aim of this prospective controlled trial (National Trial Registration TC 6559) is to evaluate the treatment efficacy of bone-anchored maxillary protraction in growing unilateral complete cleft lip and palate patients with Class III malocclusion on 3D surface models derived from a Cone Beam CT, and on 2D cephalograms in comparison with thre (...truncated)