This study aimed to evaluate the reliability of cone-beam computed tomography (CBCT) imaging of the maxillary structures and the postoperative dentoskeletal, nasal airway, periodontal, and facial soft tissue changes after surgically assisted rapid palatal expansion (SARPE). A systematic review of the literature on CBCT analysis of SARPE was performed. The PubMed, Embase, and Cochrane Library databases were searched. Nine articles were included, involving a total of 228 patients. The general trend was tooth-borne distraction with pterygomaxillary dysjunction. A systematic increase in all transverse dimensions at the dentoalveolar and dental levels, as well as a certain degree of tipping and extrusion of the anchorage teeth and tipping of the skeletal segments, was detected. Soft tissue findings reflected the underlying dentoalveolar changes. A decrease in the buccal alveolar bone thickness and alveolar crest level occurred. Results confirm that CBCT is an accurate and reliable method to assess anatomical changes after SARPE. Although this systematic review provides valuable preliminary information about the effects of SARPE, results should be interpreted with caution due to the low level of evidence of the publications, great heterogeneity among study groups regarding outcome variables and surgical–orthodontic protocols, and lack of long-term data.
Surgically assisted rapid palatal expansion (SARPE) is the procedure of choice to manage severe transverse maxillary deficiencies in adult patients. It has been reported to improve stability compared to non-surgical rapid palatal expansion (RPE). Indeed, SARPE releases bone structures that are resistant to expansion forces. There is no consensus regarding the areas of major resistance to maxillary expansion and the number of osteotomies required to obtain a parallel opening of the midpalatal suture, but some authors relate pterygomaxillary dysjunction to a parallel expansion.
The majority of studies evaluating the transverse skeletal effects of maxillary expansion have been based on conventional cephalometric analysis using postero-anterior radiographs, occlusal views, or dental casts. The inherent limitations of all planar two-dimensional (2D) projections, such as magnification, distortion, and difficulties in landmark identification and superimposition of the anatomical structures, result in images with low accuracy and reliability and explain why these methods have been open to some criticism. With the introduction of three-dimensional (3D) imaging modalities, a more detailed and accurate evaluation of the dentoskeletal structures has become feasible compared with conventional 2D radiographs. In particular, several studies have now analysed the efficacy of SARPE using cone beam computed tomography (CBCT). Its high potential for evaluating the maxillary structures has been confirmed, mainly due to its advantages of good resolution and accuracy (only about 2% magnification), precision, non-invasiveness, lower effective radiation dose, and shorter acquisition times (60 s).
Within this context, the purpose of the present study was to conduct a systematic review of the literature on CBCT imaging and analysis of maxillary changes after SARPE in order to investigate the reliability of CBCT for maxillary analysis and to study changes in the midpalatal suture, skeletal and dental changes, changes in the nasal cavity, periodontal effects, and soft tissue facial changes.
Materials and methods
This systematic review focused on non-growing, non-syndromic human patients with skeletal maxillary transverse deficiencies treated with SARPE and studied with CBCT. The variables studied (dentoskeletal, midpalatal, nasal, periodontal, and soft tissue changes) were compared before and after treatment. Case reports, case series with a sample of n < 10, oral communications, posters, and theses were excluded.
The PICOS principle (participants, intervention, comparisons, outcomes, and study design) was followed.
A systematic review of the literature on SARPE and analysis with CBCT was performed. An electronic search in the PubMed (National Library of Medicine, NCBI), Cochrane Library, and Embase databases was performed in January 2015 and subsequently updated in July 2016. Table 1 shows the key words used to build the search strategy. The electronic search was completed by a manual search of the reference lists of selected publications.