Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e6

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Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial studyq Mohammad Zandi a, Amirfarhang Miresmaeili b, *, Ali Heidari a a

Department of Oral and Maxillofacial Surgery (Head: Mohammad Zandi, DDS, MSc.), Hamedan University of Medical Sciences, Hamedan, Iran Department of Orthodontics (Head: Amirfarhang Miresmaeili, DDS, MSc.), Hamedan University of Medical Sciences, Shahid Fahmideh Street, Hamedan, Iran b

a r t i c l e i n f o

a b s t r a c t

Article history: Paper received 27 November 2013 Accepted 10 February 2014

Aim: To evaluate and compare the short-term (post-retention) skeletal and dental changes following bone-borne and tooth-borne surgically assisted rapid maxillary expansion (SARME) using cone beam computed tomography (CBCT). Subjects and methods: In this randomized clinical study, 30 patients with transverse maxillary deficiency underwent either tooth-borne (n ¼ 15) or bone-borne (n ¼ 15) SARME. Before treatment and immediately after the consolidation period, CBCT was obtained and the nasal floor width, interdental root distance, palatal bone width and interdental cusp distance were measured at first premolar and first molar regions of maxilla. Results: Twenty eight patients completed the study protocol. In both tooth-borne (n ¼ 13) and boneborne (n ¼ 15) groups the highest degree of expansion occurred in the dental arch, followed by palatal bone, and nasal floor (V-shaped widening in coronal dimension). The amount and pattern of expansion was comparable between anterior and posterior maxillary regions in each group (parallel posteroanterior expansion) and between the two groups. Conclusion: Dental and skeletal effects of tooth-borne and bone-borne devices were comparable. The overall complication rate was negligible. Selection of an expansion device should be based on each individual patient’s requirements. Future long-term clinical trial studies to evaluate the stability and relapse of these two techniques are recommended. Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Keywords: Tooth-borne Bone-borne Rapid maxillary expansion Cone beam computed tomography

1. Introduction Maxillary transverse (horizontal) deficiency may exist as an isolated entity or may be associated with other dentofacial deformities such as cleft palate, mandibular prognathism, mandibular deficiency, and anterior open bite. It is typically characterized by unilateral or bilateral crossbites, crowded teeth, and a constricted and tapered maxillary arch. In children and growing adolescents, conventional orthodontic rapid maxillary expansion can successfully be accomplished to treat maxillary constriction. However, in non-growing adolescents and adult patients, because of fusion of q The trial is registered at irct.ir, number IRCT138904124303N1. * Corresponding author. Tel.: þ98 811 8239064, þ98 9121395653 (mobile); fax: þ98 811 8234014. E-mail addresses: [email protected], [email protected] (A. Miresmaeili).

the midpalatal and lateral maxillary sutures and increased skeletal resistance, surgically assisted rapid maxillary expansion (SARME) is the treatment of choice. In these cases, traditionally, a tooth-borne palatal expander (Hass or Hyrax appliance) is used to do the maxillary expansion. Because these appliances are fixed to the teeth, they deliver a large amount of force into the anchor teeth, periodontal tissues, and alveolar bone during expansion, and may cause buccal tipping of the anchor teeth, outward rotation of the palatal bone segments, and complications such as buccal root exposure of anchor teeth, periodontal problems, buccal root resorption, and speech difficulties (Harzer et al., 2006; Aziz and Tanchyk, 2008; Koudstaal et al., 2009; Verstraaten et al., 2010). To avoid these complications, several types of bone-borne devices, which deliver expansion force directly to the palatal bone, have been introduced. It has been reported that bone-supported devices have several advantages over tooth-supported expanders including

http://dx.doi.org/10.1016/j.jcms.2014.02.007 1010-5182/Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

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M. Zandi et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e6

ability to be placed in an extremely narrow maxilla, avoiding dental tipping and periodontal problems, avoiding root resorption and exposure, low palatal profile, and creating true orthopaedic palatal expansion. However, bone-borne devices are expensive, their placement during surgery is time consuming, and their removal needs a second operation (Pinto et al., 2001; Gerlach and Zahl, 2005; Harzer et al., 2006; Aziz and Tanchyk, 2008; Verstraaten et al., 2010). Dental and skeletal changes after either tooth-borne or boneborne SARME have been evaluated in several studies (Matteini and Mommaerts, 2001; Pinto et al., 2001; Gerlach and Zahl, 2005; Ramieri et al., 2005; Harzer et al., 2006; Lagravère et al., 2006; Baraldi et al., 2007; Aziz and Tanchyk, 2008; Altug-Atac et al., 2010; Verstraaten et al., 2010; Seeberger et al., 2011). Because boneborne SARME is a relatively new technique (introduced in 1999), most of the previous research on this treatment modality have been retrospective studies or prospective case report and series (Mommaerts, 1999; Verstraaten et al., 2010). By reviewing the published literature, especially systematic review and meta-analysis researches on SARME, the authors of the present study found few studies directly comparing the dentoskeletal effects of bone-borne and tooth-borne SARME (Suri and Taneja, 2008; Koudstaal et al., 2009; Landes et al., 2009; Laudemann et al., 2010; Verstraaten et al., 2010; Nada et al., 2012; Vilani et al., 2012). These studies had some shortcomings including non-randomized clinical trial design (using various types of expanders and surgical techniques in each study group based on practitioners’ preferences) and assessment of dentofacial changes using dental casts and/or plain radiographs instead of advanced imaging techniques. Therefore, a randomized clinical trial to evaluate and compare the dentoskeletal effects of bone-supported versus tooth-supported SARME using an advanced imaging technique was required. The aim of the present study was to evaluate and compare the short-term (post-retention) skeletal and dental changes following bone-borne and tooth-borne SARME using cone beam computed tomography (CBCT) imaging.

Bruges, Belgium) was placed at the end of the surgery at the level of the second premolars, high on the palate. After a latency period of 7 days, the distractors were activated at an approximate rate of 0.5e0.6 mm/day until an overexpansion of 2e3 mm was observed on either side. Then, the distractors were locked and kept in place for a consolidation period of approximately 4 months. At the end of consolidation period, the distractors were removed and a transpalatal retainer was placed. In both groups, cone beam computed tomography (CBCT) scans were performed before operation and immediately after completion of the consolidation period by using a Newtom 3G scanner (AFP Imaging, Elmsford, NY, USA). The scanning parameters were 120 kV, 2 mA, with a field of view of 1200 and a 0.4-mm voxel size. To assess the skeletal and dental changes after SARME, the following distances (Fig. 1) were measured on the coronal CBCT images before treatment (BT) and immediately after the end of the consolidation period (AT): NFW4: Nasal floor width measured at the area of the first premolars, 5 mm above the most inferior part of the nasal floor. NFW6: Nasal floor width measured at the area of the first molars, 5 mm above the most inferior part of the nasal floor. PBW4: Palatal bone width measured at the level of a line connecting the palatal root apex of the first premolars. PBW6: Palatal bone width measured at the level of a line connecting the palatal root apex of the first molars. IRD4 (Interdental Root Distance 4): The distance between the palatal root apex of the right and left first premolars. IRD6 (Interdental Root Distance 6): The distance between the palatal root apex of the right and left first molars. ICD4 (Interdental Cusp Distance 4): The distance between the mesiopalatal cusp tip of the right and left first premolars.

2. Material and methods Thirty consecutive patients with transverse maxillary deficiency who were referred by orthodontists for SARME to the Department of Oral and Maxillofacial Surgery were included in this prospective randomized clinical study. Patients were randomly assigned to bone-borne (n ¼ 15) and tooth-borne (n ¼ 15) groups using a computer generated random sequence. The patients were aged between 15 and 27 years, and consisted of 11 males and 19 females. The inclusion criteria included skeletal maturity and the presence of one or more of the clinical signs of transverse maxillary deficiency such as dental crossbite, crowded teeth, and constricted maxillary arch. The exclusion criteria were congenital maxillofacial deformities, prior orthodontic and surgical treatment on maxilla, prior maxillary trauma, and transverse maxillary deficiency that could be corrected by orthodontic treatment alone. This study was approved by the Research Ethics Committee of the University, and the written informed consent of all patients was obtained. The surgical procedure, which was the same for all patients and performed by the same surgeon, consisted of osteotomy of the lateral maxillary wall from the piriform rim to the pterygomaxillary junction, midline osteotomy between the central incisors, and pterygomaxillary disjunction, not including the releasing of the nasal septum. In the tooth-borne group, a Hyrax appliance (Dentaurum, Ispringen, Germany) was passively bonded to the maxillary first premolars and the first molars before surgery. In the bone-borne group, a transpalatal distractor (TPD, Surgi-Tec,

Fig. 1. The distances measured at the first premolar (A) and first molar (B) regions: NFW, Nasal floor width; IRD, Interdental root distance; PBW, Palatal bone width; ICD, Interdental cusp distance, 4: first premolar area, 6: first molar area.

Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

M. Zandi et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e6

ICD6 (Interdental Cusp Distance 6): The distance between the mesiopalatal cusp tip of the right and left first molars. For calculation of the amount of expansion at any area of interest, pretreatment distance was subtracted from posttreatment distance (AT  BT). To determine the inter-observer and intraobserver reliability, all measurements were performed twice with an 8-week interval, and by two observers who were blind to the type of treatment being used at the time of measurements. Statistical analyses were carried out using SPSS version 16.0 (SPSS inc., Chicago, IL, USA). At first, descriptive statistics were calculated to give a rough outline of the results. The Levene’s test was used to test the equality of variances. For comparison of outcomes between the two pooled, independent groups (tooth-borne versus bone-borne SARME) an unpaired Student’s t-test was used. To analyse the skeletal and dental changes after SARME within each group, the paired t-tests were applied. Using Pearson’s correlation test, the level of the inter-observer and intra-observer agreements was evaluated. In this study, p < 0.05 was considered statistically significant.

3. Results Thirty patients were entered into this study, but 2 patients did not complete the research protocol and were excluded. The age and sex data of the remaining 28 patients is presented in Table 1; no difference was observed among the groups. The duration of the surgical procedure ranged between 60 and 90 min. Mean appliance opening in the tooth-borne and bone-borne groups were 7.8  2.8 mm and 7.3  2.0 mm, respectively. It was not significantly different between the two groups. The only complication observed in this study was mild extrusion of a first premolar to which the expansion device was anchored in one patient. Except for oedema and haematoma, the remaining 27 patients had no significant problem intra- or postoperatively. Intra- and inter-observer correlations were performed at a confidence interval of 95%. In the study, intra-observer and interobserver correlations ranged from 0.70 (for NFW4) to 0.96 (for ICD6) and from 0.60 (for NFW6) to 0.95 (for IRD6), respectively (p value ranged from 0.0001 to 0.001). Evaluation of the skeletal and dental changes after SARME within tooth-borne group revealed that in the first premolar region the greatest expansion occurred in the dental arch (7.23  2.77), followed by palatal bone (4.38  1.75) and nasal floor (1.62  0.65). All the differences were statistically significant (p < 0.001). Similarly, expansion of the dentoskeletal structures in the first molar region occurred mostly in the dental area (7.12  2.87), followed by palatal bone (3.92  1.48) and nasal floor (1.54  0.52); all the differences were statistically significant (p < 0.0001). The amount and pattern of expansion observed in the first premolar region did not significantly differ from that in the first molar region. In addition, in both first premolar and molar regions, the amount of Table 1 Demographic data of the patients.

Age (years) Range Mean (SD) Gender Female Male

Tooth-borne group (n ¼ 13)

Bone-borne group (n ¼ 15)

15e27 20.31 (3.64)

15e23 19.4 (2.53)

9 (69%) 4 (31%)

10 (67%) 5 (33%)

NS: nonsignificant; SD: standard deviation.

p-value

NS NS

3

Table 2 Skeletal and dental changes (in mm) following SARME within tooth-borne group (n ¼ 13). Variables

AT  BT Mean  SD

NFW4 NFW6 PBW4 PBW6 ICD4 ICD6 NFW4 PBW4 PBW4 ICD4 NFW6 PBW6 PBW6 ICD6 PBW4 IRD4 PBW6 IRD6

1.62 1.54 4.38 3.92 7.23 7.12 1.62 4.38 4.38 7.23 1.54 3.92 3.92 7.12 4.38 5.38 3.92 4.81

                 

0.65 0.52 1.75 1.48 2.77 2.87 0.65 1.75 1.75 2.77 0.52 1.48 1.48 2.87 1.75 2.01 1.48 2.09

Mean difference

95% CID

Sig. (2-tailed)

Lower

Upper

0.08

0.31

0.46

0.673

0.46

0.20

1.12

0.152

0.11

0.87

1.10

0.803

2.77

3.75

1.79

0.000

2.85

4.18

1.52

0.001

2.38

3.23

1.54

0.000

3.20

4.61

1.77

0.000

1.00

2.18

0.18

0.189

0.89

2.14

0.37

0.152

BT: before treatment; AT: after treatment; SD: standard deviation; CID: confidence interval of the difference; NFW4 and NFW6: nasal floor width at the first premolar and first molar regions, respectively; PBW4 and PBW6: palatal bone width at the first premolar and first molar regions, respectively; IRD4 and IRD6: interdental root distance at the first premolar and first molar regions, respectively; ICD4 and ICD6: interdental cusp distance at the first premolar and first molar regions, respectively.

increase in interdental root distance was not significantly different from that in palatal bone width (Table 2). In the bone-borne group, in both first premolar and first molar regions, the dental arch showed the greatest expansion, followed by the palatal bone and the nasal floor. In the region of the first premolars, the mean expansion gain at the areas of the dental arch, palatal bone, and nasal floor were 6.73  2.15, 4.53  2.02, and 1.47  0.52, respectively (p < 0.001). In the first molar region, the mean expansion gain observed at the areas of the dental arch, palatal bone, and nasal floor were 6.53  2.67, 4.33  1.23, and 1.33  0.49, respectively (p < 0.004). Dental and skeletal changes observed in the first premolar region did not significantly differ from that in the molar region. Furthermore, in both first premolar and molar regions, the mean expansion gain at the area of the root apices does not differ from that at the area of the palatal bone (Table 3). Comparison of the dentoskeletal changes after SARME between tooth-borne and bone-borne groups revealed that the amount and pattern of the expansion at various areas did not differ significantly between the two groups (Table 4). 4. Discussion Practical clinical experience has shown that SARME is reliable and effective for the correction of transverse maxillary deficiency in skeletally mature patients. However, there is no consensus in the literature regarding the type of distractor (tooth-borne or boneborne) that should be used in SARME to provide the best dental and skeletal results and stability (Suri and Taneja, 2008; Verstraaten et al., 2010; Vilani et al., 2012). Tooth-borne devices transmit the expansion force to the anchor teeth and may cause buccal tipping of the anchor teeth, maxillary dentoalveolar tipping and several complications including periodontal problems, root resorption, tooth extrusion, cortical bone resorption and fenestration, speech problems, and relapse. It is claimed that bone-borne devices, which deliver the expansion force directly to the palatal bone, produce parallel expansion of the

Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

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M. Zandi et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e6

Table 3 Skeletal and dental changes (in mm) following SARME within bone-borne group (n ¼ 15). Parameters (AT  BT)

Mean  SD

NFW4 NFW6 PBW4 PBW6 ICD4 ICD6 NFW4 PBW4 PBW4 ICD4 NFW6 BPW6 PBW6 ICD6 PBW4 IRD4 PBW6 IRD6

1.47 1.33 4.53 4.33 6.73 6.53 1.47 4.53 4.53 6.73 1.33 4.33 4.33 6.53 4.53 4.40 4.33 4.50

                 

0.52 0.49 2.02 1.23 2.15 2.67 0.52 2.02 2.02 2.15 0.49 1.23 1.23 2.67 2.02 1.68 1.23 1.83

Mean difference

95% CID

Sig. (2-tailed)

Lower

Upper

0.14

0.15

0.42

0.334

0.20

0.65

1.05

0.621

0.20

0.50

0.90

0.550

3.06

4.20

1.94

0.000

2.20

3.38

3.99

0.001

3.00

3.75

2.24

0.000

2.20

3.59

0.81

0.004

0.13

0.44

0.71

0.628

0.17

0.76

0.43

0.560

BT: before treatment; AT: after treatment; SD: standard deviation; CID: confidence interval of the difference; NFW4 and NFW6: nasal floor width at the first premolar and first molar regions, respectively; PBW4 and PBW6: palatal bone width at the first premolar and first molar regions, respectively; IRD4 and IRD6: interdental root distance at the first premolar and first molar regions, respectively; ICD4 and ICD6: interdental cusp distance at the first premolar and first molar regions, respectively.

palatal halves, keeping segmental and tooth tipping and associated complications to a minimum (Gerlach and Zahl, 2005; Harzer et al., 2006; Suri and Taneja, 2008; Koudstaal et al., 2009; Verstraaten et al., 2010). However, the results of studies evaluating dental and skeletal changes following either tooth-borne or bone-borne

Table 4 Comparison of the skeletal and dental changes following SARME between toothborne and bone-borne groups (in mm). Parameters

NFW4 BT AT AT  NFW6 BT AT AT  SPW4 BT AT AT  SPW6 BT AT AT  DPW4 BT AT AT  DPW6 BT AT AT 

Tooth-borne group (n ¼ 13)

Bone-borne group (n ¼ 15)

Mean difference

Sig. (2-tailed)

Mean  SD

Mean  SD

BT

22.54  2.85 24.15  2.82 1.61  0.65

21.60  3.16 23.07  3.37 1.47  0.52

0.94 1.09 0.15

0.419 0.368 0.506

BT

26.31  2.78 27.85  2.82 1.54  0.52

25.00  3.30 26.33  3.44 1.33  0.49

1.31 1.51 0.21

0.271 0.219 0.291

BT

19.88  5.39 24.19  5.03 4.31  1.77

19.53  3.33 24.07  3.62 4.53  2.02

0.35 0.12 0.22

0.835 0.940 0.758

BT

24.42  4.18 28.35  3.68 3.92  1.48

25.67  2.16 30.00  2.85 4.33  1.23

1.24 1.65 0.41

0.322 0.192 0.432

BT

22.96  3.84 29.46  4.54 6.51  1.76

21.87  2.92 28.80  2.96 6.93  2.52

1.09 0.66 0.42

0.400 0.647 0.640

BT

30.88  5.34 37.92  3.92 7.12  2.87

29.67  3.31 36.20  3.53 6.53  2.67

1.21 1.72 0.59

0.468 0.232 0.583

BT: before treatment; AT: after treatment; SD: standard deviation; NFW4 and NFW6: nasal floor width at the first premolar and first molar regions, respectively; PBW4 and PBW6: palatal bone width at the first premolar and first molar regions, respectively; IRD4 and IRD6: interdental root distance at the first premolar and first molar regions, respectively; ICD4 and ICD6: interdental cusp distance at the first premolar and first molar regions, respectively.

SARME are controversial, and few studies have directly compared these two techniques. In the study, in both tooth-borne and bone-borne groups, we observed that the dental arch, the palatal vault, and the nasal floor widened posteroanteriorly in a nearly parallel fashion (viewed from occlusal aspect). Accordingly, Chamberland and Proffit (2011), and Koudstaal et al. (2009) found that tooth-borne devices caused parallel expansion of the dental arch in an anterioposterior plane. However, Kilic et al. (2013) and Han et al. (2006) demonstrated a higher amount of expansion in the first premolar area than in the molar area following tooth-borne SARME. Zemann et al. (2009) reported a higher amount of expansion in the intercanine area than between the molars, while Anttila et al. (2004) reported the opposite. Seeberger et al. (2011) reported a V-shaped opening of the nasal floor and the palatal arch, but a parallel expansion of the tooth-bearing parts of the alveolar crest following tooth-borne SARME, while Goldenberg et al. (2008) suggested that the greatest expansion occurred in the most inferior and anterior region of the maxilla. A factor that may affect the pattern of dental and skeletal expansion in posteroanterior plane, and its importance in SARME is highly controversial in the literature is the pterygomaxillary suture osteotomy. Study by Bays and Greco (1992) on tooth-borne SARME revealed more expansion in posterior than anterior region of the maxilla when pterygomaxillary disjunction was performed, while Vasconcelos et al. (2006) and Han et al. (2006) observed the opposite. Studies by Matteini and Mommaerts (2001), Pinto et al. (2001), and Ramieri et al. (2005) on bone-borne SARME demonstrated parallel dental arch expansion when TPD was placed at the molar level and pterygomaxillary disjunction was performed, and more expansion in anterior than posterior dental arch when TPD was placed at the premolar molar level and no pterygomaxillary disjunction was done. However, in this study, in spite of placing the TPD at the level of the premolar teeth and performing pterygomaxillary osteotomy, we observed that the dental arch, the palatal vault, and the nasal floor widened in a nearly parallel fashion, which was in agreement with the findings of the research by Koudstaal et al. (2009). These variations in the pattern of expansion following SARME may be partly related to the technique used for pterygomaxillary disjunction. Improper placement and inclination of the osteotome at the pterygomaxillary suture may lead to partial separation of the suture and limited widening of the posterior maxillary area (Pereira et al., 2012). In the study, assessment of the coronal CBCT images showed that both tooth-borne and bone-borne techniques resulted in outward rotation (tipping) of the maxillary dentoalveolar segments. The greatest expansion occurred at the dental arch level with a progressive reduction in expansion toward the nasal floor (V-shaped expansion). In agreement with the findings of this study, most of the previous researches reported rotational movement (tipping) of the maxillary segments after both tooth-borne and bone-borne SARME (Goldenberg et al., 2008; Koudstaal et al., 2009; Chamberland and Proffit, 2011; Kilic et al., 2013), although Zemann et al. (2009) and Pinto et al. (2001) observed little tipping of the maxillary segments after tooth-borne and bone-borne SARME, respectively. Bone-borne devices are placed at a higher position in the palatal vault than tooth-borne appliances, and are claimed to expand the dentoalveolar segments in a parallel fashion. However, in SARME, there is more resistance to expansion at the level of palatal roof than at the dental arch area, because the two maxillary halves are still connected to the skull even after completion of the osteotomies, and the mucoperiosteum over the midpalatal suture gives resistance to expansion. Therefore, the centre of resistance to expansion is always far from the position of the distractor which is usually several millimetres below the palatal roof. For these

Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

M. Zandi et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e6

reasons, bone-borne devices act like a lever and cause outward rotation rather than parallel expansion of the palatal halves. In this study, the pattern and amount of expansion following tooth-borne and bone-borne SARME were not significantly different between the two groups. Most of the previous studies on SARME were consisted of case reports or series. The results of the few papers that directly compared the dentoskeletal effects of tooth-borne and bone-borne SARME were in agreement with the findings of the present study (Koudstaal et al., 2009; Landes et al., 2009; Laudemann et al., 2010; Nada et al., 2012). In a randomized clinical trial study by Koudstaal et al. (2009), the dentoskeletal effects of tooth-borne (using Hyrax) and bone-borne (using TPD and Rotterdam) SARME were evaluated and compared. Assessments of pretreatment and posttreatment dental casts and cephalograms revealed no significant difference between the two groups. In a prospective cohort study by Nada et al. (2012), the long term effects of tooth-borne and bone-borne SARME (using Hyrax and TPD, respectively) were evaluated three-dimensionally. This study demonstrated that the mean expansion at the level of the root apices and dental arch, and the average changes in the posterior maxillary segments were not significantly different between the two groups. In a study by Landes et al. (2009), short-term effects of tooth-borne and bone-borne SARME were compared. Evaluation of preoperative and postexpansion (three months later) 3D computed tomography of the patients showed that Bone-borne devices caused bigger overall skeletal and dental maxillary expansion declining from anterior to posterior region. However, Laudemann et al. (2010) followed up the patients studied by Landes et al. (2009) for 20.5  1.34 months and re-evaluated them using 3D scanned cast models, and found no significant differences between the two groups. This study revealed comparable dental and skeletal changes following tooth-borne and bone-borne SARME. The overall complication rate in both treatment modalities was negligible. To the authors, each technique has its own advantages and disadvantages, and selection of the distraction device for SARME should be based on each individual patient’s requirements. It was also observed that the findings of the previously published researches on SARME were very conflicting which might be due to differences in research methodologies, distractor types, expansion protocols, surgical techniques, and methods used to assess the outcomes. The present research had the following strengths: a randomized clinical trial study design; operation of all patients by the same surgeon using uniform surgical technique, expansion protocol, and distraction device (in each group); and using an advanced imaging technique (CBCT) for assessment of the outcomes. This study was limited to immediate post retention changes after SARME without assessment of long-term stability and relapse, and was based on a relatively small sample size. Therefore, future randomized controlled clinical trial studies based on bigger study groups with long-term follow up to evaluate the stability and relapse after SARME was recommended. 5. Conclusion Both tooth-borne and bone-borne devices produced a V-shaped expansion of the dentoskeletal structures with more widening at the dental arch level than in the nasal floor area (segmental tipping). Posteroanteriorly, parallel expansion of the dental arch, palatal bone, and nasal floor was observed. The amount and pattern of expansion was not significantly different between tooth-borne and bone-borne SARME. The overall complication rate was negligible in both techniques. Selection of the distraction device for SARME should be based on each individual patient’s requirements.

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Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

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Please cite this article in press as: Zandi M, et al., Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: A randomized clinical trial study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/ j.jcms.2014.02.007

Short-term skeletal and dental changes following bone-borne versus tooth-borne surgically assisted rapid maxillary expansion: a randomized clinical trial study.

To evaluate and compare the short-term (post-retention) skeletal and dental changes following bone-borne and tooth-borne surgically assisted rapid max...
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