Three-dimensional radiological evaluation of secondary alveolar bone grafting in cleft lip and palate patients: a systematic review

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

BACKGROUND

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 defected maxilla.

PURPOSE

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 CLP CBCTs.

METHODS

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 CLP CBCTs.

RESULTS

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 ± $\pm$ 0.02 on the restored maxilla and 0.84 ± $\pm$ 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 ± $\pm$ 0.08 mm. The relative volume error of the cleft defect was0.09 ± $0.09\pm$ 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.

CONCLUSIONS

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 acquisition burdens.

Validation and comparison of 2D grading scales and 3D volumetric measurements for outcome assessment of bone-grafted alveolar clefts in children

BACKGROUND

Several methods have been proposed to assess outcome of bone-grafted alveolar clefts on cone beam computed tomography (CBCT), but so far these methods have not been compared and clinically validated.

OBJECTIVES

To validate and compare methods for outcome assessment of bone-grafted clefts with CBCT and provide recommendations for follow-up.

METHODS

In this observational follow-up study, two grading scales (Suomalainen; Liu) and the volumetric bone fill (BF) were used to assess the outcome of 23 autogenous bone-grafted unilateral alveolar clefts. The mean age at bone grafting was 9 years. The volumetric BF was assessed in five vertical sections. The bone-grafted cleft outcome was based on a binary coding (success or regraft) on a clinical multidisciplinary expert consensus meeting. Grading scales and volumetric assessment were compared in relation to the bone-grafted cleft outcome (success or regraft). Reliability for the different outcome variables was analyzed with intra-class correlation and by calculating kappa values.

LIMITATIONS

The study had a limited sample size. Clinical CBCT acquisitions had a varying tube current and exposure time.

RESULTS

Volumetric 3D measurements allowed for outcome assessment of bone-grafted alveolar clefts with high reliability and validity. The two grading scales showed highly reliable outcomes, yet the validity was high for the Suomalainen grading scale but low for the Liu grading scale.

CONCLUSIONS

Volumetric 3D measurement as well as the Suomalainen grading can be recommended for outcome assessment of the bone-grafted cleft. Yet, one must always make a patient-specific assessment if there is a need to regraft.

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

BACKGROUND & 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 < .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.

An easy-to-use semi-automatic volumetric evaluation for secondary bone grafting in patients with unilateral alveolar cleft

Surgical intervention for alveolar bone formation is important in patients with alveolar cleft; however, the treatment methods and materials are still controversial. A precise evaluation method for postoperative bone formation is important for comparing outcomes and establishing the best treatment protocol. The purpose of this study is to establish a new method of evaluating surgical outcomes for patients with alveolar cleft. Computed tomography datasets from 20 patients who underwent secondary alveolar bone grafting were obtained before and 1 year after surgery. Six anatomical landmarks were used to superimpose the preoperative and mirrored preoperative volume and postoperative volume data. The cleft region was segmented by subtracting the preoperative from mirrored preoperative volume data, and the failed osteogenesis region was segmented by subtracting the postoperative volume data from the cleft region; subsequently, the bone formation ratio was calculated. Two observers performed this method using a free software 3D slicer and the average evaluation times were 12.7 and 13.2 min for observers 1 and 2, respectively. Method reliability was determined by evaluating intraclass correlation coefficients. The intra-observer intraclass correlation coefficients were 0.97 and 0.96 for observers 1 and 2, respectively. The inter-observer intraclass correlation coefficient was 0.97. Our method is practical for assessing bone formation after treatment, which does not require specific knowledge or software and can be used by ordinary physicians.

Maxillary canine position of patients with non-syndromic craniofacial disorder: a retrospective evaluation of panoramic radiographs

BACKGROUND

The study evaluates the position and displacement tendency of unerupted maxillary canines in orthodontic patients with non-syndromic craniofacial disorders (CD) compared to a control (C) group.

METHODS

Canine position and displacement tendency were evaluated using panoramic radiographs (PAN) examined with parameters such as sector classification (sectors 1-5) and inclination angles (α and β). The displacement tendency was defined as the positioning of the tip in sectors 1 or 2, as well as its combination with increased angles (α > 30° and β > 39°). In addition, the correlation of the tooth position and agenesis, cleft side, and sex was assessed.

RESULTS

A total of 116 pre-treatment PAN, divided into the CD group (n = 50; mean age 8.32 ± 2.27 years) and the C group (n = 66; mean age 10.80 ± 2.82 years), were evaluated in this study. The sector classification showed no displacement tendency in both groups. Inclination angles α/β showed a statistically significant higher displacement tendency (p = 0.01) of the CD group (n = 5) on the right side, compared to healthy subjects (n = 1). Male CD patients had a statistically significant higher displacement tendency on the right side (p = 0.03). A statistically significant correlation between cleft and non-cleft-side (p = 0.03) was found.

CONCLUSION

Patients with CD showed a statistically significant higher displacement tendency of the maxillary canine affected by the cleft side. The inclination angle was found to be the better predictor compared to the sector classification which should be considered in the orthodontic treatment planning.

Evidence Mapping and Quality Analysis of Systematic Reviews on Various Aspects Related to Cleft Lip and Palate

BACKGROUND

Management of cleft lip and palate is interdisciplinary. An evidence-mapping approach was envisaged to highlight the existing gaps in this field, using only the highest level of evidence.

OBJECTIVES

To conduct evidence mapping and quality analysis of systematic reviews and meta-analyses related to any aspect of cleft lip and palate.

SEARCH METHODS

The cleft lip and palate field was divided into 9 domains and 50 subdomains and a method of categorization of systematic reviews was established. A comprehensive search strategy was carried out in seven databases along with the search of gray literature and references of included articles.

SELECTION CRITERIA

Systematic reviews related to any aspect of cleft lip and palate, conducted by a minimum of two reviewers, with a comprehensive search strategy and adequate quality analysis were included.

DATA COLLECTION AND ANALYSIS

A self-designed, pre-piloted data-extraction sheet was used to collect information that was analyzed through an expert group discussion. Quality analysis was performed using ROBIS-I, AMSTAR 2, and the PRISMA checklist.

RESULTS

A total of 144 systematic reviews published between 2008 and 2022 were included. The largest number of these could be categorized in the therapeutic domain (n = 58). A total of 27% of the studies were categorized as inconclusive, 40% as partially conclusive, and 33% as conclusive. As per ROBIS-I, 77% of reviews had high risk of bias while 58% were graded as critically low in quality as per AMSTAR 2. The majority of systematic reviews showed low reporting errors.

CONCLUSIONS

The majority of systematic reviews related to cleft lip and palate relate to therapeutic and prognostic domains and show high risk of bias and critically low quality regardless of the source journal. The results of this paper might serve as a starting point encouraging authors to carry out high-quality research where evidence is lacking.

REGISTRATION

A multidisciplinary expert-group formulated an a priori protocol, registered in Open Science Framework (DOI 10.17605/OSF.IO/NQDV2).

Maxillary Arch Dimensions in Children with Unilateral Cleft Lip and Palate Receiving Alveolar Bone Grafting

OBJECTIVE

To analyse the maxillary arch dimensions of children aged 9 and 12 with unilateral cleft lip and palate (UCLP) who received orthodontic treatment and secondary alveolar bone grafting.

DESIGN

This retrospective cohort study was performed on 30 patients with UCLP.

SETTING

All patients were treated at the Cleft Lip and Palate Centre, which is part of the University Medical Centre Amsterdam and Academic Centre for Dentistry Amsterdam, the Netherlands.

PATIENTS/PARTICIPANTS

Children with non-syndromic UCLP who received pre- and postsurgical orthodontics combined with secondary alveolar bone grafting between the ages of 9 and 12 years were included.

MAIN OUTCOME MEASURES

Maxillary arch dimensions were assessed on 60 digitised dental casts with measurements of the intermolar widths, interpremolar widths, arch perimeters, arch lengths, arch widths, and palatal depths.

RESULTS

The results of a paired-samples t-test revealed a statistically significant increase (P < .05) in intermolar width 1, intermolar width 3, interpremolar width 1, arch perimeter, and arch width between the ages of 9 (T0) and 12 (T1). Intermolar width 2 and the palatal depth decreased statistically significantly between T0 and T1.

CONCLUSIONS

Analysis of maxillary arch dimensions of children with UCLP indicates significant changes between 9 and 12 years of age. This suggests that orthodontic treatment and secondary alveolar bone grafting can be effective in improving maxillary arch dimensions. However, there is a need for collaborative research and data collection in order to provide sensible and evidence-based care to patients with cleft lip and palate.

Rapid Maxillary Expansion Treatment in Patients with Cleft Lip and Palate: A Survey on Clinical Experience in the European Cleft Centers

Cleft lip and palate patients require complex interdisciplinary treatment, including maxillary expansion and secondary alveolar bone grafting. However, the evidence on these treatment procedures and outcomes is lacking. Therefore, this study aimed to survey the subjective observations of European maxillofacial surgeons and orthodontists on the maxillary expansion and bone grafting treatment protocols and the associated complications. An online questionnaire was sent to 131 centers. The questions assessed the participants' demographic data, maxillary expansion and alveolar bone grafting protocols, and the associated complications. Descriptive statistics and a t-test were used to analyze the data. The response rate was 40.5%. The average age for maxillary expansion was 9-10 years. The secondary alveolar bone grafting was planned 5-10 months after the expansion. The most common complications were asymmetric expansion, relapse, and fistula formation. The protocols and materials used vary widely among centers. Anatomical alterations and developmental processes, like tooth eruption adjacent to the cleft, should be seriously considered for treatment planning. This survey showed that there is still a lack of consensus on these treatment procedures. Further clinical trials should focus on long-term outcome evaluation to identify treatment components for optimal alveolar bone substitution and transversal maxillary expansion treatment in patients with clefts.

Effect of body mass index on progressive bone mineral density in patients with cleft after secondary alveolar bone grafting

BACKGROUND

Although childhood obesity matters, the association between body mass index (BMI) and bone mineral density (BMD) progression in grafted tissue after secondary alveolar bone grafting (ABG) for children with cleft alveolus is scarcely studied. Accordingly, this study explored the influence of BMI on BMD progression after ABG.

METHODS

In total, 39 patients with cleft alveolus receiving ABG at the mixed dentition stage were enrolled. Patients were classified as underweight, normal weight, or overweight or obese according to age- and sex-adjusted BMI. BMD was measured in Hounsfield units (HU) from cone-beam computed tomography scans obtained 6 months (T1) and 2 years (T2) postoperatively. Adjusted BMD (HU_{grafted tissue}/HU_pogonion, BMD_a) was used for further analysis.

RESULTS

For underweight, normal-weight, and overweight or obese patients, BMD_aT1 values were 72.87%, 91.85%, and 92.89%, respectively (p = 0.727); BMD_aT2 values were 111.49%, 112.57%, and 113.10% (p = 0.828); and density enhancement rates were 29.24%, 24.61%, and 22.14% (p = 0.936). No significant correlation was observed between BMI and BMD_aT1, BMD_aT2, or density enhancement rates (p = 0.223, 0.156, and 0.972, respectively). For patients with BMI < 17 and ≥ 17 kg/m², BMD_aT1 values were 89.80% and 92.89%, respectively (p = 0.496); BMD_aT2 values were 111.49% and 113.10% (p = 0.216); and density enhancement rates were 23.06% and 26.39% (p = 0.573).

CONCLUSION

Patients with different BMI values had similar outcomes (BMD_aT1, BMD_aT2, or density enhancement rate) after our ABG procedure in the 2-year postoperative follow-up.

3-Dimensional Craniofacial Imaging: A Template for Systematic Radiologic Evaluation for Alveolar Cleft Assessment and Planning

BACKGROUND

Imaging findings are central to the diagnosis and treatment planning decisions when managing craniofacial differences. However, limited information is published on protocols for systematic cleft imaging assessment and for effective communication of these findings.

SOLUTION

A template is presented to help guide radiologic imaging reports to acquire the relevant clinical information needed to manage patients with alveolar cleft.

A Three-Dimensional Scale for the Qualitative and Quantitative Assessments of Secondary Alveolar Bone Grafting (SABG) in Unilateral Cleft Lip and Palate Patients Using Cone-Beam Computed Tomography (CBCT)

Background The objective of our study was to derive an objective assessment scale for three-dimensional (3D) qualitative and quantitative evaluation of secondary alveolar bone grafting (SABG) using cone-bone computed tomography (CBCT) in patients with unilateral cleft lip and palate (UCLP).

Methods CBCT scans for pre- and 3-month post-SABG were reviewed for bone volume, height, width, and density of the bony bridge formed in the cleft defect in 20 patients with UCLP. Basic descriptive and principal component analysis was used to extract the various sub-components of the scale. Spearman's correlation was used to check the validity of the scale, and intra-class coefficient (ICC) and Cronbach's α were calculated to establish the reliability and retest applicability of the scale.

Results Each CBCT scan was assessed in five areas: cementoenamel junction (CEJ), root apex, root midpoint, 3 and 6 mm below CEJ, and tabulated in percentiles of 20, 25, 40, 50, 60, and 75 for all the parameters (bone volume, density, and width). These scores were validated when correlated to the scale given by Kamperos et al. Cronbach's α for the domains demonstrated acceptable to excellent internal consistency. The ICC showed good test–retest reliability having a range of scores from 0.89 to 0.94.

Conclusion The proposed scale for the 3D assessment of SABG in patients with UCLP provides gradation for the objective assessment of the bony bridge. This gradation enables the qualitative and quantitative assessments of the bony bridge, thus allowing each clinician to judge SABG more conclusively.

Correlation between alveolar cleft morphology and the outcome of secondary alveolar bone grafting for unilateral cleft lip and palate

Background

Secondary alveolar bone grafting (SABG) is an integral part of the treatment for cleft lip and alveolus and cleft lip and palate. However, the outcome of SABG was not satisfactory as expected, factors that affecting the outcome were still controversial. The aims of this study were to summarize a new method for the classification of alveolar cleft morphology in patients with unilateral cleft lip and alveolus or unilateral cleft lip and palate, to evaluate the correlation between the morphology and SABG outcomes, to identify factors that might predict the outcomes.

Methods

The characteristics of the cleft morphologies of 120 patients who underwent SABG were observed using the preoperative Cone-Beam Computed Tomography (CBCT) images. 52 patients who had CBCT scans performed at least 6 months after SABG were included for the evaluation of outcomes. Both categorical and continuous evaluation methods were measured. Correlations between cleft morphology and SABG outcomes were assessed using the Pearson correlation coefficient in SPSS 27.0.0.

Results

A new method for the classification of cleft morphology was summarized:type I, prism type (labial defect size ≥ palatal defect size; nasal defect size ≥ occlusal defect size); type II, prism’ type (labial defect ≥ palatal defect; nasal defect < occlusal defect); type III, inverted prism type (palatal defect ≥ labial defect); type IV, funnel type (presented as a significantly narrow defect area in the middle towards the vertical dimension); and type V, undefinable (extremely irregular morphology can’t be defined as any of the above types). Categorical evaluation showed 8 failure, 11 poor, 12 moderate, and 21 good results, while the average bone filling rate was 59.24 ± 30.68%. There was a significant correlation between the cleft morphology and categorical/continuous evaluation outcome (p < 0.05).

Conclusion

The new method for the classification of alveolar cleft morphology summarized in this study was comprehensive and convenient for clinical application. Both categorical and continuous methods should be used for radiographic assessments in patients undergoing SABG. The chances of a successful procedure might be better when the patient has type I or IV morphology, in which the shape is like a funnel in the relatively palatal or occlusal area towards the vertical dimension. A relatively great amount of bone resorption was observed in most patients.

Trial registration Chinese clinical trial registry; registration number: ChiCTR2100054438.

A Novel and Practical Protocol for Three-Dimensional Assessment of Alveolar Cleft Grafting Procedures

OBJECTIVE

To evaluate the reproducibility and accuracy of a new, easy-to-use volumetric assessment of the alveolar cleft.

DESIGN

Twelve cone-beam computed tomography (CBCT) datasets of patients with a unilateral cleft lip, alveolus, and palate were evaluated by two investigators. Residual alveolar cleft calcified volume one year after surgery was analyzed by using standardized landmarks to determine the borders of the cleft defect and semi-automatically segment the alveolar cleft defect.

RESULTS

The Dice-coefficient between observers for the segmented preoperative alveolar cleft defect was 0.81. Average percentage of residual alveolar cleft calcified material was 66.7% one year postoperatively.

CONCLUSIONS

This study demonstrates a reliable and practical semi-automatic three-dimensional volumetric assessment method for unilateral clefts using CBCT.

Diagnostic Protocols for Alveolar Clefting and Barriers to Acquiring Imaging: A Survey of ACPA-Approved Cleft Teams in the United States

OBJECTIVE

To report current diagnostic protocols, practices, and barriers related to imaging of alveolar clefting among American Cleft Palate-Craniofacial Association (ACPA)-approved cleft/craniofacial teams.

METHODS

An electronic survey was sent to 162 ACPA-approved teams in the United States. Key items were team location, venue of orthodontic treatment, imaging modality(s) and access, barriers to imaging, billing, imaging protocols including team members involved in decisions pre- and post-alveolar bone grafting (ABG), and craniofacial fellowship status of team orthodontist(s).

RESULTS

A total of 66 responses were received (40.7%). Responding teams were university-based (47%), hospital-based (42.4%), and independent clinics (10.6%). Orthodontic treatment for most patients was in private practice (53%). On-site 2-dimensional (2D) and 3-dimensional (3D) dental imaging capabilities were reported by 42% of teams; 29% have no on-site imaging. One or more barrier(s) to acquiring imaging were reported by 67%, with insurance challenges reported by 47%. Most teams bill medical payors for cleft-related dental imaging (58%). Pre- and post-ABG imaging was most frequently 3D (35% and 36%, respectively). Surgeons and orthodontists commonly evaluate ABG timing and outcome together (53%-65%). Periapical radiographs were included significantly more often in cleft imaging protocols by orthodontists with versus without fellowship training (P = .011, P = .04).

CONCLUSIONS

Barriers to acquiring imaging are frequent. 3D is the most common imaging pre- and post-ABG. Our study endorses multi-level advocacy for improved medical insurance coverage of diagnostic cleft-related dental imaging to decrease barriers to providing timely care.

Validation of a 3D methodology for the evaluation and follow-up of secondary alveolar bone grafting in unilateral cleft lip and palate patients

OBJECTIVE

The aim of the study was to propose and validate a method for three-dimensional (3D) quantitative assessment of secondary alveolar bone grafting (SABG) and its stability in time for patients with unilateral cleft lip and palate (UCLP).

SETTINGS AND SAMPLE POPULATION

Ten non-syndromic UCLP patients (9 males and 1 female with a mean age of 9.5 ± 0.9 years) undergoing SABG with good quality preoperative, immediate postoperative (6 weeks) and 6 months postoperative Cone Beam Computed Tomography (CBCT) scans were selected.

MATERIALS AND METHODS

The preoperative and 6 months postoperative scans were registered onto the immediate postoperative scan. The bone-grafted region was defined on the immediate postoperative scan and refined on the registered preoperative scan resulting in a 3D volume. The residual bone graft was calculated by applying threshold based segmentation on the registered 6 months postoperative scan within the segmented bone graft volume of the previous step. Inter and intra observer tests using intra-class correlation coefficient (ICC) were applied comparing the volumes of the 3D models.

RESULTS

An excellent reliability was found for inter and intra observers with ICC ≥ 0.95.

CONCLUSIONS

The presented method proved to be reliable for volumetric assessment of the alveolar bone graft in UCLP patients, as well as to assess the percentage of bone resorption during follow-up.

Progressive Comparison of Density Assessment of Alveolar Bone Graft in Patients with Unilateral and Bilateral Cleft

(1) Background: Continuing to observe the grafted bone mineral density (BMD) is essential to ensure the success of alveolar bone grafting (ABG) in patients with cleft lip and palate. This study elaborates on three methods that can be used to evaluate the progressive BMD. (2) Methods: Forty patients with unilateral or bilateral clefts receiving ABG were enrolled. Cone beam computed tomography (CBCT) scans were taken at 6 months (T1) and 2 years (T2) postoperatively. In CBCT, measurements were obtained on three different planes using the circle located 1 mm from the adjacent teeth (Method A), the largest circle within the defect (Method B), or the central circle with a diameter of 2 mm (Method C). The BMD was the average density of the three planes and was adjusted by pogonion density. Bland–Altman plots were used to evaluate the agreement of each method. Inter-rater reliability was confirmed by the intraclass correlation coefficient (ICC). (3) Results: For Method A, B, and C, the mean-adjusted BMD (BMD/pogonion density, BMD_a) was 17.44%, 17.88%, and 17.69%, respectively, at T1 (p = 0.495), and 22.51%, 22.87%, and 22.74%, respectively, at T2 (p = 0.690); the density enhancement rates were 40.54%, 38.92%, and 43.15% (p = 0.382). Significant differences between the BMD_a at T1 and T2 were observed (p < 0.001, <0.001, and 0.001, for Method A, B, and C, respectively). The volume of the grafted tissue remained stable during T1 and T2, and no significant correlation between density enhancement rate and volume loss was observed. (4) Conclusions: A significant increase in the BMD of grafted tissue was observed in the 2-year postoperative follow-up. The three methods for measuring BMD_a via CBCT can be applied in post-ABG evaluations.

Alveolar Volume Following Different Timings of Secondary Bone Grafting in Patients with Unilateral Cleft Lip and Palate. A Pilot Study

This study was intended to evaluate the relationship between secondary alveolar bone grafting (SABG) timing and the alveolar volume in patients with unilateral cleft lip and palate (UCLP). The material consisted of CTs of 35 patients (17 males, 18 females) with UCLP who underwent a one-stage primary cleft repair at a mean age of 8.4 months and SABG at different timings ranges of 1.8–18.8 years. The mean age at CT was 17.2 years. The relative coefficient (Ꞷ) which was independent from factors such as individual maxillary size, gender or age at the CT was introduced in order to compare volumes of the cleft-side in relation to the non-cleft-side alveolus. Pearson correlation coefficient r between Ꞷ coefficient and SABG timing was weak negative (r = −0.34, p = 0.045). The multiple regression analysis implied that the dependent variable-Ꞷ coefficient was associated with independent variables (cleft repair and SABG timings and age at CT) with r² = 0.228. Only patient’s age at SABG explained the dependent variable (p = 0.003). The study cautiously indicates a tendency to larger alveolar volume following earlier timing of SABG. Nevertheless, the further research on a larger group of patients should be performed before formulating any clinical indications.

Outcome after secondary alveolar bone grafting among patients with cleft lip and palate at 16 years of age: a retrospective study

OBJECTIVE

To evaluate the outcome of secondary alveolar bone grafting (SABG) in patients with cleft lip and palate at 16 years of age and to identify predictors associated with surgical failure.

STUDY DESIGN

This retrospective follow-up included 91 patients with 100 cleft palates treated with SABG at a mean age of 9.2 years. The possible predictors for surgical failure analyzed were sex, dental development stadium, type of cleft, side, tooth erupting into the graft, cortical boundary, presence of a lateral incisor, extraction, preoperative expansion, oral hygiene, retention device, and age. The outcome variable for surgical success was Bergland score I and II. Surgical outcome was analyzed at 16 years of age based on intraoral radiographs, according to the Bergland index. Statistical analyses included estimation of odds ratios for predictor variables.

RESULTS

The post-SABG success rate was 91% (Bergland score I and II) with a mean follow-up of 7.2 years. Surgical failure was significantly associated with poor oral hygiene.

CONCLUSIONS

This study revealed a high success rate (91%) at a mean of 7.2 years post-SABG. Poor oral hygiene significantly increased the risk of surgical failure. This suggests that increased perioperative measures to maintain good oral health could reduce surgical failure.

Intra- and Interobserver Reliability of Bone Volume Estimation Using OsiriX Software in Patients with Cleft Lip and Palate Using Cone Beam Computed Tomography

The objective of the current study was to evaluate intra- and interobserver bone volume measurements and effect of orientation on the reliability of bone volume evaluation in as-acquired vis-à-vis oriented cone beam computed tomography scans using Osirix software and possible correlation between gender, age, and bone volume required. For this, 31 cone beam computed tomography (CBCT) scans of 14 girls and 17 boys (aged 9–13) with unilateral cleft lip and/or palate who met the inclusion criteria were analyzed. Efficacy and reliability of third party software Osirix for bone volume calculation was assessed using as acquired and oriented volumes by three specialists (a radiologist, an orthodontist, and an oral maxillofacial surgeon). The dataset and readings were anonymized to prevent any bias. Two-way mixed model analysis on as-acquired and oriented observations exhibited intra-class coefficient (ICC) values ≥ 0.90. Wilcoxon signed rank test (p = 0.10) and Kruskal–Wallis ANOVA (p = 0.46) indicated that although a clinical difference in volume assessment was seen between as-acquired and oriented observations (inter-observer and intra-observer), it was statistically insignificant. Spearman’s bi-variate correlation analysis revealed a significant relation between the type (side) of cleft and bone volume required to fill the defect (p < 0.05). Although there was clinical difference in bone volume measurement by the three observers, it was insignificant statistically. Clefts on the left side in the patients had significantly more bone required than the right side, whereas age and gender had no relation with bone needed to fill the defect. OsiriX software provided good reliability in measurements of bone volume.

Comparative Volume Analysis of Alveolar Defects by 3D Simulation

A precise volumetric assessment of maxillary alveolar defects in patients with cleft lip and palate can reduce donor site morbidity or allow accurate preparation of bone substitutes in future applications. However, there is a lack of agreement regarding the optimal volumetric technique to adopt. This study measured the alveolar bone defects by using two cone-beam computed tomography (CBCT)-based surgical simulation methods. Presurgical CBCT scans from 32 patients with unilateral or bilateral clefts undergoing alveolar bone graft surgery were analyzed. Two hands-on CBCT-based volumetric measurement methods were compared: the 3D real-scale printed model-based surgical method and the virtual surgical method. Different densities of CBCT were compared. Intra- and inter-examiner reliability was assessed. For patients with unilateral clefts, the average alveolar defect volumes were 1.09 ± 0.24 and 1.09 ± 0.25 mL (p > 0.05) for 3D printing- and virtual-based models, respectively; for patients with bilateral clefts, they were 2.05 ± 0.22 and 2.02 ± 0.27 mL (p > 0.05), respectively. Bland–Altman analysis revealed that the methods were equivalent for unilateral and bilateral alveolar cleft defect assessment. No significant differences or linear relationships were observed between adjacent different densities of CBCT for model production to obtain the measured volumes. Intra- and inter-examiner reliability was moderate to good (intraclass correlation coefficient (ICC) > 0.6) for all measurements. This study revealed that the volume of unilateral and bilateral alveolar cleft defects can be equally quantified by 3D-printed and virtual surgical simulation methods and provides alveolar defect-specific volumes which can serve as a reference for planning and execution of alveolar bone graft surgery.