Secondary Alveolar Bone Grafting Research Articles

Evaluation of Secondary Alveolar Bone Grafting for Unilateral Complete Cleft Alveolus: A Retrospective Cone Beam Computed Tomography-Based Study.

Background: In patients with cleft lip and palate (CLP), secondary alveolar bone grafting (SABG) with particulate cancellous bone marrow (PCBM) is recommended. Objective: To compare bone graft outcomes in patients with unilateral CLP, when SABG is completed before or after canine tooth eruption (ACE or BCE), as measured by cone beam computed tomography (CBCT). Methods: Patients were allocated into two cohorts, ACE and BCE. The outcomes were evaluated using CBCT, followed by univariate and multifactorial analyses. Results: A total of 468 patients (age 11.61 ± 4.03 years; male/female 288/180) were analyzed, including 282 in the BCE group (9.41 ± 1.59 years, 175/107) and 186 in the ACE group (14.95 ± 4.31 years, 113/73). Although 5-level assessment revealed no significant difference in clinical success rate (>4 points) between the BCE and ACE groups (53.90% vs. 47.85%, p = 0.20), BCE group showed significantly higher rate of bone bridges formation (73.05% vs. 62.90%, p = 0.02), which can be attributed to variations in orthodontic participation and follow-up time. Independent predictors of graft failure were wide cleft, severe oronasal fistula, no palatal bone wall, and insufficient PCBM filling (p < 0.01). Conclusions: SABG should be performed before canine eruption with more aggressive PCBM filling and oral fistula management.

Commentary on: "Evolution of Secondary Alveolar Bone Grafting for Unilateral Complete Cleft Alveolus: A Retrospective Cone Beam Computed Tomography-Based Study" by Jing et al.

Commentary on: "Evolution of Secondary Alveolar Bone Grafting for Unilateral Complete Cleft Alveolus: A Retrospective Cone Beam Computed Tomography-Based Study" by Jing et al.

Evaluation of Using Platelet Rich Fibrin Versus Collagen Membrane for Enhancing Healing of Secondary Grafted Alveolar Cleft: A Randomized Controlled Trial

PurposeThe purpose of this study was aimed to compare the efficiency of using autologous platelets rich fibrin versus a resorbable collagen membrane in secondary alveolar bone grafting. Materials and methodsPatients were randomly allocated to the three treatment groups; group (1) twelve children in whom nasal layer of alveolar cleft were repaired using autologous platelet rich fibrin with autogenous chin bone, group (2) twelve children in whom nasal layer of alveolar cleft were repaired using Bovine collagen membrane type I (Colla-D) with autogenous chin bone, and group (3) twelve children in whom bony alveolar cleft was grafted with autogenous chin bone after construction of watertight nasal floor was completed. ResultsThe study population comprised thirty-six patients with alveolar clefts, Patients ranging in age from (7 to 12 years). At the last follow up period all groups had stable healing conditions, good and radiological outcomes in terms of alveolar bone height bordering the teeth mesially and distally, as well as the incorporation of the graft material with the surrounding bone. ConclusionThe use of a PRF membrane and a collagen membrane as an interposition layer between the nasal layer and the autogenous chin bone graft enhanced bone formation and density in alveolar clefts compared to the control group.

Adaptable cascaded registration for personalized maxilla completion and cleft defect volume estimation.

Cone-beam computed tomography (CBCT) images provide high-resolution insights into the underlying craniofacial anomaly in patients with cleft lip and palate (CLP), requiring non-negligible annotation costs to measure the cleft defect for the guidance of the clinical secondary alveolar bone graft procedures. Considering the cumbersome volumetric image acquisition, there is a lack of paired CLP CBCTs and normal CBCTs for learning-based anatomical structure restoration models. Nowadays, the registration-based method relieves the annotation burden, though one-shot registration and the regular mask are limited to handling fine-grained shape variations and harmony between restored bony tissues and the defectedmaxilla. This study aimed to design and evaluate a novel method for deformable partial registration of the CLP CBCTs and normal CBCTs, enabling personalized maxilla completion and cleft defect volume prediction from CLPCBCTs. We proposed an adaptable deep registration framework for personalized maxilla completion and cleft defect volume prediction from CLP CBCTs. The key ingredient was a cascaded partial registration to exploit the maxillary morphology prior and attribute transfer. Cascaded registration with coarse-to-fine registration fields handled morphological variations of cleft defects and fine-grained maxillary restoration. We designed an adaptable cleft defect mask and volumetric Boolean operators for reliable voxel filling of the defected maxilla. A total of 36 clinically obtained CLP CBCTs were used to train and validate the proposed model, among which 22 CLP CBCTs were used to generate a training dataset with 440 synthetic CBCTs by B-spline deformation-based data augmentation and the remaining for testing. The proposed model was evaluated on maxilla completion and cleft defect volume prediction from clinically obtained unilateral and bilateral CLPCBCTs. Extensive experiments demonstrated the effectiveness of the adaptable cleft defect mask and the cascaded partial registration on maxilla completion and cleft defect volume prediction. The proposed method achieved state-of-the-art performances with the Dice similarity coefficient of 0.90 0.02 on the restored maxilla and 0.84 0.04 on the estimated cleft defect, respectively. The average Hausdorff distance between the estimated cleft defect and the manually annotated ground truth was 0.30 0.08 mm. The relative volume error of the cleft defect was 0.08. The proposed model allowed for the prediction of cleft defect maps that were in line with the ground truth in the challenging unilateral and bilateral CLP CBCTs. The results suggest that the proposed adaptable deep registration model enables patient-specific maxilla completion and automatic annotation of cleft defects, relieving tedious voxel-wise annotation and image acquisitionburdens.

The Effect of Platelet-Rich Fibrin and Platelet-Rich Plasma in Secondary Alveolar Bone Grafting in Cleft Lip and Palate Patients: A Systematic Review.

(1) Background: Cleft lip, alveolus, and palate are the most common congenital abnormalities in the world, occurring in one in seven hundred live births. Secondary alveolar bone grafting (SABG) is usually performed when the permanent canine root shows one-half to two-thirds of root development. To improve the surgical outcome, supplemental grafting materials such as platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) have been used as an adjunct. This review is designed to assess the efficacy of PRF and PRP in improving the outcome of SABG. (2) Methods: A comprehensive literature search was performed until 13 October 2022 on MEDLINE, EMBASE, The Cochrane Library, and Pubmed. The full text of potentially relevant studies was reviewed, and only randomised clinical trials (RCTs) were included based on the inclusion criteria. (3) Results: A total of 656 studies were screened, of which four were included for final review. All of the four included studies that evaluated the quantitative or qualitative surgical outcome in varied ways. (4) Conclusions: Results of this review suggest that both PRF or PRP and control group (without the use of PRF/PRP) achieved similar successful outcomes in bone height, bone density, and bone volume in both qualitative and quantitative assessment.

Postoperative Radiologic Imaging in Secondary Alveolar Bone Grafting for Cleft Lip and Palate: A Systematic Review and Meta-Analysis.

Radiographs (XRs), computed tomography (CT) scans, and cone-beam CT (CBCT) scans are utilized for assessment of secondary alveolar bone graft (SABG) in patients with cleft lip and palate (CLP). However, the optimal choice for imaging modality remains unclear. This study compares the image fidelity and safety profile for XR, CT, and CBCT in the assessment of patients with CLP who have undergone SABG. Articles from MEDLINE and Elsevier Embase were screened. The primary outcome was graft success rate. Secondary outcomes were percent-by-volume of graft maintained and patient safety, defined by radiation exposure. A random effects model was used to calculate the pooled outcomes for each imaging modality. Chi-squared analysis was used to compare pooled outcomes between different imaging modalities. Of the 149 articles identified initially, 14 were included. Computed tomography exhibited a significantly higher image fidelity demonstrated by a lower graft success rate (62.0%) compared with both XR (72.6%, P<0.01) and CBCT (69.8%, P<0.01). Cone-beam CT had the lowest reported percent-by-volume of graft maintained (32.1%). Computed tomography had a higher mean radiation dosage (39.7 milligray) than what has been reported for both XR and CBCT. Computed tomography demonstrated lower graft success rates than both XR and CBCT, possibly indicating a higher image fidelity. However, compared with CBCT, CT may have a higher radiation exposure. Randomized trials and longitudinal studies are necessary to perform a direct comparison between CT and CBCT and to correlate the image fidelity of these modalities with clinical outcomes.

Cleft Laterality Dental Arch Relationship Outcomes for Children with Unilateral Cleft Lip and Palate in New Zealand.

To investigate cleft laterality dental arch relationship outcomes of children with non-syndromic complete unilateral cleft lip and palate (UCLP) in New Zealand. A retrospective nationwide study. Virtual 3D orthodontic study models collected prior to undertaking secondary alveolar bone grafting. A total of 104 patients with UCLP (L = 80: R = 24). Four calibrated assessors used the GOSLON Yardstick and 100 mm Visual Analogue Scale (VAS) to score the randomised models on 2 separate assessment sessions. Weighted Kappa were used to determine the intra/inter-rater reliability for the GOSLON and correlations for the VAS. Intra-rater reliability ranged from 0.57-0.88 (GOSLON) and 0.45-0.93 (VAS). Inter-rater reliability ranged from 0.62-0.86 (GOSLON) and 0.64-0.93 (VAS).GOSLON scores for the left UCLP were 31.2% for good/very good; 26.3% for fair; 42.5% for poor/very poor while the right UCLP scored 8.3% for good/very good; 37.5% for fair; 54.2% for poor/very poor. The mean VAS for left and right UCLP were 53.4 (sd 22.5) and 44.6 (sd 17.1) respectively. Neither the GOSLON nor VAS differences reached statistical significance (both P = .08). From a clinical perspective right UCLP had worse dental arch relationship outcomes, however, these differences failed to reach statistical significance. Further studies using larger sample sizes are required to determine if cleft laterality is an important consideration when investigating UCLP dental arch outcomes.

Developmental characteristics of the permanent upper lateral incisor in unilateral cleft lip and palate.

This study aims to provide insights into the developmental characteristics of the upper lateral incisor in individuals with unilateral clefts. Panoramic radiographs of a consistent group of Caucasian children taken over time (ages 6, 9, and 12) were extensively reviewed. The study assessed the distribution pattern, eruption path, tooth development, and crown size of the upper lateral incisor within the cleft region. The most commonly observed distribution pattern was the lateral incisor located distal to the cleft, accounting for 49.2% of cases. Furthermore, a significant delay in tooth development of the upper lateral incisor on the cleft side was noted at ages 6 and 9 (p > 0.001). Compared with the non-cleft side, these incisors often erupted along the alveolar cleft and exhibited microdontia (88.3%, p < 0.041). Lateral incisors on the cleft side display unique distribution patterns, microdontia, and delayed tooth development. Careful monitoring of the cuspid eruption is essential, as it can influence the eruption of the lateral incisor. A comprehensive understanding of the development of the upper lateral incisor relative to the cleft is vital for determining its prognosis over time. The position of the upper lateral incisor can also influence the timing and prognosis of secondary alveolar bone grafting. Preserving the upper lateral incisor favors arch length, perimeter, and symmetry in individuals with unilateral clefts.

Three-dimensional evaluation of secondary alveolar bone grafting in patients with unilateral cleft lip and palate: A 2-3 year post-operative follow-up.

The present study aims to quantitatively assess secondary alveolar bone graft (SABG) resorption in unilateral cleft lip, alveolus and palate (UCLAP) patients in a 2-3 year longitudinal follow-up setting by using a validated 3D protocol. Furthermore, the potential relation of SABG resorption with maxillary canine position and a number of patient-related factors was investigated. UCLAP patients who underwent SABG and had good quality CBCT images at the following timepoints were included in the study: pre-operative (T0), immediate (T1), 6 months (T2) and either 1-2 years (T3) or 2-3 years (T4) post-operative. The final bone grafted region was defined on the T1 scans and refined in the registered T0 scans. The bone graft after resorption was determined by applying threshold-based segmentation on the registered T2, T3 or T4 scans within the segmented bone graft volume. The position of the canines was determined at every timepoint at the cleft and non-cleft side. Forty-five UCLAP patients (mean age 9.0 ± 1.3 years) were included. In the first 6 months after SABG, 43.6% bone resorption was recorded. 2-3 years post-operative, 56% bone resorption was found if the maxillary canine was not yet erupted and 42.7% if it erupted through the graft. The vertical position of the canines was significantly higher on the cleft side at T3. The present study reports significant SABG resorption over time. However, no correlation was found between SABG resorption and canine position, nor between other patient-related factors.

Radiographic Assessment of Cleft Alveolar Bone Defects: A Preliminary Comparison of Periapical and Cone Beam Computed Tomography Images

Background &amp; Purpose Accurate radiographic assessment of secondary alveolar bone grafting (SABG) is critical in evaluating SABG outcomes in patients with cleft lip and palate. This study compared Periapical (PA) and Cone beam computed tomography (CBCT) grading of SABG outcomes and conducted an analysis of agreement rate between the two imaging modalities. Methods A retrospective chart review was performed of patients who underwent secondary alveolar bone grafting at a single institution. Bone quality of the alveolar cleft site was assessed at three root levels of the adjacent teeth on PA and CBCT images. Results 48 patients had pre- or post-operative images with both CBCT and PA that were appropriate for comparison. A total of 174 alveolar bone sections (three root levels of adjacent teeth in 58 pairs) were graded on CBCT and PA images. Agreement of CBCT grading with PA grading was 41.3% (72/174) overall. CBCT assessments rated bone quality lower than PA grading in 51.2% (89/174) of sections. CBCT had higher grading than PA image grading in 7.5% (13/174) of sections. The weighted Cohen Kappa value for comparison of CBCT and PA readings was 0.17, indicating a low rate of agreement. Wilcoxon signed rank test demonstrated that the difference between grading on CBCT and PA assessments was statistically significant ( P &lt; .001). Conclusions CBCT and PA readings demonstrated an overall low rate of agreement in the assessment of cleft alveolar bone. This investigation suggests that PA radiographs have lower sensitivity in detecting poor bone grafting outcomes.

Alveolar Bone Grafting in Unilateral Cleft Lip and Palate: Impact of Timing on Palatal Shape.

Alveolar bone grafting (ABG) is a critical surgical intervention in patients with a cleft of the alveolus, aimed at reconstructing the alveolar ridge to facilitate proper eruption, periodontal support, and alignment of adjacent permanent teeth. The optimal timing for ABG remains debated, with late secondary ABG between the ages of 9 and 11 being widely adopted. This study compared the palatal shapes of 28 children at a mean age of 9.5 years (SD = 0.7) who underwent early secondary ABG at a mean age of 2.1 years (SD = 0.6) or 33 children at a mean age of 10.8 years (SD = 1.5) who underwent late secondary ABG at a mean age of 8.6 years (SD = 1.3) to 60 non-cleft controls at a mean age of 8.6 years (SD = 1.2). The palatal shapes were captured with 239 landmarks digitized on the palate on a digital model. Utilizing geometric morphometric methods, i.e., generalized Procrustes superimpositions, principal component analysis, and permutation tests, we assessed the impact of ABG timing on palatal morphology. The first five principal components (PCs) explained 64.1% of the total shape variability: PC1 = 26.1%; PC2 = 12%; PC3 = 11.9%; PC4 = 7.8%; and PC5 = 6.4%. The Procrustes distance between both cleft groups and the control group was more than twice as large as the Procrustes distance between the early ABG and late ABG groups. Nonetheless, all intergroup differences were statistically significant. Our findings suggest that early ABG has a limited negative effect on palatal shape, providing comparable outcomes to late ABG. The study highlights the potential suitability of early ABG, challenging conventional practices and encouraging further exploration into its long-term effects on maxillary growth.

Bioglass 45S5, a relevant alternative to autogenous harvesting for secondary alveolar bone grafts in clefts? Retrospective study of one hundred surgeries

The secondary alveolar bone grafting (SABG) step restores the continuity of the alveolar bone necessary for dentition. Faced with the complications of autografts, synthetic biomaterials such as Bioglass (BG) 45S5 have been proposed. The objective was to evaluate the success rate of SABG with the addition of BG 45S5 and to highlight the prognostic factors.Patients who underwent operation between 2015 and 2021 and had follow-up cone-beam computed tomography (CBCT) were analyzed. Multivariate analysis was performed to determine factors influencing radiographic success. A total of 102 SABG were analyzed. They were unilateral total cleft lip and palate (49, 48.0%). The mean age at surgery was 9.32 ± 3.09 years. Surgeries were performed mainly outside a syndromic context and without a family history after orthodontic preparation.The radiographic success rate at 1 year was 80.4%. Mixed dentition stage (odds ratio [OR] = 7.3, p = 0.024), absence of syndromic context (OR = 20.7, p = 0.024) and female sex (OR = 4.88, p = 0.021) were factors predictive of surgical success.The use of BG 45S5 instead of autograft is relevant for SABG, with a 1-year success rate of over 80%. The stage of mixed dentition, the absence of syndromic context, and female sex were factors for good prognosis.

A Comparative Analysis of the Minimally Invasive Approach against the Traditional Open Harvesting Technique for Obtaining Iliac Bone Grafts in Secondary Alveolar Bone Grafting Procedures for Patients with Cleft Palate

Abstract: Secondary alveolar bone grafting (SABG) is an important surgery that people with cleft palate must have in order to have good dental rehabilitation. The goal of SABG is to create a stable alveolar ridge. The choice of graft picking method has a big effect on how well the surgery invasive harvesting methods used in iliac bone graft (SABG) procedures. The main points of the study are how happy the patients are, how these works and how well the patients do in the long run. This review study looks at the pros and cons of both traditional open harvesting and minimally methods have improved, and the results and problems that have happened.

Current State of Clinical Trials Regarding Alveolar Bone Grafting.

Alveolar ridge defects develop because of surgery, trauma, infection, or congenital malformations. Alveolar ridge defects can be resolved using an osseous replacement. The primary outcomes of osseous replacement are the maintenance of contour; the elimination of dead space, the reduction of postoperative infection; and the increase in bony and soft tissue healing. Recent research shows promising developments in dental bone grafts. This review presents the results of several clinical trials and provides updates on current alveolar bone grafting. In May 2023, we searched Clinicaltrials.gov for interventional clinical trials related to alveolar bone grafting. A total of 66 clinical trials were included using Boolean Operators AND, OR, NOT we used the “advanced search” option with the search terms [Alveolar Bone Grafting] OR [Ridge Preservation] OR [Dental Bone Grafting] OR [Ridge Augmentation]. Reviewed publications are summarized. 28 out of the 66 trials were successfully completed. None of the trials had offered an invitation to enroll, and only one was terminated. Autograft was the most prevalent kind of grafting, at 28 out of 66, more than twice as prevalent as allograft, which ranked second at 12 out of 66. this study shows a lack of variety in location, low results provided, and low clinical trials regarding bone rejection. The focus of published trials was mainly on cleft palate rehabilitation using secondary alveolar bone grafting, and the usage of L-prf, rh-FGF-2, rhBMP2, and hyaluronic acid in association with alveolar bone grafting showed remarkable results concerning bone's osteoconduction, osteoinduction, and osteogenesis.

Long-term radiographic and periodontal evaluations of the bone-grafted alveolar cleft region in young adults born with a UCLP.

Studies addressing the periodontal health of the teeth surrounding the bone-grafted cleft in patients born with unilateral cleft lip and palate disagree on whether periodontal health is compromised. To determine periodontal health differences between the cleft and the non-cleft sides nearly a decade after secondary alveolar bone grafting. This prospective, controlled (split-mouth design) study comprised an intraoral apical radiographic and a periodontal examination of 40 consecutive patients from one centre (n = 26 males) who had undergone bone grafting at mean age of 10.2 years (±1.6). Probing pocket depth, gingival index, gingival recession, and radiographic bone support were assessed. No significant difference occurred in probing pocket depth between teeth at cleft and non-cleft sites (OR 1.8, P = .488). Gingival recession was present at 6.6% of all examined sites on the cleft side and at 1.7% on the non-cleft side (OR 17.3, P < .001). Gingival recession occurred most often on the buccal and disto-buccal surfaces of the central incisor on the cleft side. The gingival index was significantly higher on the cleft side (OR 8.0, P < .001). The Bergland index was I or II in most patients (87%). Recruitment of eligible patients was lengthy. The teeth on the cleft side had high levels of gingival inflammation. Few pathological gingival pockets, however, were found. Shallow gingival recessions frequently occurred around the central incisor on the cleft side. Teeth in the bone-grafted cleft region generally had good bone support.

Postoperative Facial Edema Following Alveolar Bone Grafting: A Prospective Cohort Study

Objectives: The secondary alveolar bone graft (ABG) is one of the key components in the treatment of cleft lip and palate. However, an ABG is commonly accompanied by postoperative facial edema. Although appropriate assessment of facial edema can facilitate the early detection of major postoperative complications, the usual course of swelling post-ABG is not yet fully understood. The present, prospective cohort study was conducted to clarify the typical course of facial swelling post-ABG.

A Comparison of Three-Dimensional Cone Beam Computed Tomography Outcomes between Early versus Late Secondary Alveolar Bone Grafting in Patients with Unilateral Cleft Lip and Palate

A Comparison of Three-Dimensional Cone Beam Computed Tomography Outcomes between Early versus Late Secondary Alveolar Bone Grafting in Patients with Unilateral Cleft Lip and Palate

Extracorporeal Shockwave Therapy Improves Outcomes Following Secondary Alveolar Bone Grafting

Background: Recent studies have reported that extracorporeal shock wave therapy (ESWT) enhances bone formation during mandibular distraction osteogenesis. This study seeks to investigate the clinical outcomes in children undergoing ESWT alongside secondary alveolar bone grafting procedures at our institution. Methods: Retrospective review of all children that underwent secondary alveolar cleft bone grafting with adjunctive ESWT between 2019 and 2021. Variables including age, gender, cleft type, cleft width, pre-operative cleft dentition, volume of bone graft placed intraoperatively, ESWT settings, pain medication utilization, length of stay (LOS), follow-up, cone beam computed tomography (CBCT) data, and complications were recorded. Results: Twenty patients met inclusion criteria. Median age at surgery was 9 years (range 8-16). Four (20%) patients were female; 16 (80%) were male. Eight (40%) patients had bilateral alveolar clefts; 12 (60%) had unilateral clefts. All (100%) patients were discharged on the day of surgery. Twelve (60%) patients required a median of 1.3 oxycodone doses post-operatively (range 0-6.5). All patients received ESWT treatments intra and post-operatively. All patients demonstrated an increase in bone graft volume visualized on CBCT: median increase of 6.8% (range 1.3%-35.7%) between 106.5 days (17.5% of ideal visualized, range 5%-42%) and 245.5 days (27.9% of ideal, range 8%-55.7%). Three (15%) patients experienced minor complications. Conclusions: Initial outcomes suggest that ESWT may expedite visualization of bone consolidation and facilitate recovery without increasing complications. ESWT could further represent an opportunity to improve care in craniofacial surgery. Pertinent considerations, the role of standardized assessment protocols, and future directions will be reviewed.

Root development differences between cleft-adjacent teeth on the cleft side in comparison to their analogs on the noncleft side in patients with nonsyndromic cleft lip and palate who received secondary alveolar bone grafting.

To assess differences in root development between the cleft side (CS) and noncleft side (NCS) for permanent maxillary central incisor and canine longitudinally in patients with nonsyndromic complete unilateral cleft lip and palate (cUCLP) who received secondary alveolar bone grafting (SABG) and to evaluate the effects of SABG on the acceleration of root development of these teeth. Permanent maxillary central incisors and canines of 44 subjects with nonsyndromic cUCLP who had all their cleft-related surgeries performed by the same surgeon were analyzed retrospectively from chart notes and radiographs. Panoramic and periapical radiographs at time point 1 (T1) (age, 7.55 years), at SABG (time point 2 [T2], 10.13 years), and a minimum of 2 years after SABG were studied. Root development rating scores on the NCS and CS were compared using paired t-tests and analyses of proportions. Mean root development score differences (NCS - CS) for canines and central incisors were greatest at T2 but diminished at time point 3 (T3). A larger proportion of teeth on the CS trailed the teeth on the NCS by at least 1 point at T2 than at T1 or T3, with the smallest proportion being observed at T3. The change in root development scores from T1 to T2 and from T2 to T3 showed relative CS acceleration from T2 to T3, indicating a catch-up of root development of cleft-adjacent teeth after SABG. Root development of cleft-adjacent central incisors and canines is slow in comparison with their noncleft analogs. Root development of these teeth accelerates following SABG.

A Comparison of Three-Dimensional Cone Beam Computed Tomography Outcomes Between Early Versus Late Secondary Alveolar Bone Grafting in Patients with Unilateral Cleft Lip and Palate

A Comparison of Three-Dimensional Cone Beam Computed Tomography Outcomes Between Early Versus Late Secondary Alveolar Bone Grafting in Patients with Unilateral Cleft Lip and Palate