Evaluation of Bone Height and Bone Mineral Density Using Cone Beam Computed Tomography After Secondary Bone Graft in Alveolar Cleft. J Craniofac Surg. 2015;26:1463-1466. [PMID: 26114510 DOI: 10.1097/scs.0000000000001766]

Three-dimensional comprehensive evaluation of unilateral alveolar cleft bone grafting with iliac bone and chin bone blocks

In this study, we aimed to provide guidance for selecting bone grafting materials in cases of alveolar clefts. Twenty-nine patients with unilateral complete alveolar clefts were categorized into three groups based on the bone grafting material used: Group A (iliac bone block grafts), Group B (iliac cancellous bone grafts), and Group C (chin bone block grafts). Cone-beam computed tomography (CBCT) data were analyzed using Mimics 19.0 software. Results showed that Group A had the highest bone formation rate, with significant differences observed between Groups A and B, as well as between Groups B and C. Group A and Group C had the highest proportion of Type I in volume assessment, while Group B had the highest proportion of Type III, Significant differences were observed in the distribution of volume assessment scores among the three groups. Bone height measurement results indicated that buccal-side measurement points had a higher proportion of Type I bone height than palatal-side measurement points. Bone width measurement results showed that Type I bone width was highest in Group C, while Type IV bone width was highest in Group B. Significant differences were observed in the distribution of implanted bone width among the three groups. Total grafting scores indicated that Types A and D were predominant in Groups A and C, while Group B had the highest proportion of Type D. Significant differences were observed in the distribution of total grafting scores among the three groups. The comprehensive evaluation method provides accurate assessment of alveolar cleft bone grafting outcomes and is applicable in clinical settings. Based on the results, we consider both iliac bone blocks and chin bone blocks as suitable materials for alveolar cleft bone grafting. Grafting material selection should consider preoperative gap volume measured using CBCT, required bone quantity, donor site complications, and overall clinical needs.

Collagen type I-based recombinant peptide promotes bone regeneration in rat critical-size calvarial defects by enhancing osteoclast activity at late stages of healing

Introduction

We recently demonstrated the bone-forming potential of medium-cross-linked recombinant collagen peptide (mRCP) in animal models of bone defects. However, these studies were limited to a 4-week observation period; therefore, in the present study, we aimed to further evaluate mRCP as a suitable bone graft material for the alveolar cleft by analyzing its bone-forming potential, osteogenic-inducing ability, and biodegradation over an extended period of 12 weeks, using a rat critical-size calvarial defect model.

Methods

Using Sprague-Dawley rats, we created critical-size calvarial defects through a surgical procedure. The defects were then filled with 3 mg of mRCP (mRCP group) or 18 mg of Cytrans® (CA) granules, which has a carbonate apatite-based composition resembling natural bone, was used as a reference material (CA group). For negative control, the defects were left untreated. Bone volume, total bone volume (bone volume including CA granules), and bone mineral density (BMD) in the defect were assessed using micro-computed tomography (μ-CT) at 0, 4, 8, and 12 weeks after implantation. Using histomorphometric analyses of hematoxylin and eosin (H&E)-stained sections, we measured the amount of newly formed bone and total newly formed bone (new bone including CA granules) in the entire defect site, as well as the amount of newly formed bone in the central side, two peripheral sides (left and right), periosteal (top) side, and dura mater (bottom) side. In addition, we measured the amount of residual bone graft material in the defect. Osteoclasts and osteoblasts in the newly formed bone were detected using tartrate-resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) staining, respectively.

Results

Bone volume in the mRCP group increased over time and was significantly larger at 8 and 12 weeks after surgery than at 4 weeks. The bone volume in the mRCP group was greater than that of the CA and control groups at 4, 8, and 12 weeks after implantation, and while the total bone volume was greater in the CA group after 4 and 8 weeks, the mRCP group had comparable levels of total bone volume to that of the CA group at 12 weeks after implantation. The BMD of the mRCP group reached similar levels to native calvaria bone at the same time point. H&E-stained sections revealed a larger amount of newly formed bone 12 weeks after implantation in the mRCP group compared to that of the CA and control groups. The total newly formed bone at 12 weeks after implantation was on par with that in the CA group. Furthermore, at the defect site, the area of newly formed bone was larger on the peripheral and dura mater sides. Notably, the number of osteoclasts in the mRCP group was higher than in the CA and control groups and peaked 8 weeks after implantation, which coincided with the timing of the greatest resorption of mRCP. Although the ALP-positive area was greater in the mRCP group compared to other groups, we did not detect any significant changes in the number of osteoblasts over time.

Conclusion

This study demonstrated the bone-forming potential of mRCP over an extended period of 12 weeks, suggesting that mRCP sufficiently resists resorption to promote bone formation through induction of osteoclast activation in the late stages of the healing period.

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.

Orthodontic treatment protocols in patients with alveolar clefting: a survey of ACPA-approved cleft teams in the United States

OBJECTIVES

To describe pre- and post-alveolar bone graft (ABG) practice protocols of orthodontists associated with American Cleft Palate-Craniofacial Association-approved cleft and cleft/craniofacial teams.

MATERIALS AND METHODS

Electronic survey responses from team orthodontists were evaluated regarding pre-ABG orthodontic treatment type(s), timing of post-ABG imaging and post-ABG orthodontic treatment, and craniofacial orthodontic fellowship training status of the team orthodontists. A P value of <.05 was considered significant.

RESULTS

Of 31 responding orthodontists, 54.8% had fellowship training and 45.2% did not. Pre-ABG orthodontic preparation ranged from solely maxillary expansion for alveolar segment alignment (35.5%) to a combination of maxillary expansion for both alveolar segment alignment and posterior crossbite correction, anterior tooth alignment, and anterior crossbite correction (19.4%). Most captured post-ABG radiographs prior to orthodontic tooth movement (90.3%). Orthodontists began treatment at least 6 months (35.5%), 2-4 months (32.3%), or 4-6 months (29%) post-ABG. No significant differences were found when comparing fellowship subgroups. In addition, 47.1% of fellowship-trained orthodontists deferred post-ABG orthodontic treatment to at least 6 months post-operatively, vs 21.4% of non-fellowship trained orthodontists (P = .14).

CONCLUSIONS

A large variation in approaches is evident in pre-ABG orthodontic treatment types and timing of post-ABG treatment. Post-operative imaging is pursued by most orthodontists to assess graft status prior to initiating orthodontic treatment. Additional clinical research is needed to support providers in their decision-making with regard to evidence-based approaches.

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.

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.

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.

Assessment of Outcomes of Immediately Loaded Dental Implants in Orofacial Cleft Patients: Protocol for a Single-Arm Clinical Trial

BACKGROUND

Orofacial cleft, one of the most common congenital deformities, presents with a plethora of defects, subjecting the patient to a multitude of treatments from a young age. Among the oral hard tissue problems, absence of a maxillary permanent tooth in the cleft region either due to congenital absence or extraction due to compromised prognosis is a common finding. Conventionally, the missing tooth is replaced using a removable or fixed partial denture; however, the treatment modality does not satisfactorily meet patient expectations. The most recent decade has seen increasing use of dental implants in the cleft region; however, the outcome of an immediately loaded dental implant is still elusive for orofacial cleft patients.

OBJECTIVE

This protocol is for a single-arm clinical trial aimed at determining the treatment outcome of immediately loaded dental implants in patients with a nonsyndromic orofacial cleft.

METHODS

Patients meeting the set criteria will be sequentially enrolled until a sample size of 30 dental implants is met and will undergo the proposed treatment according to the predecided protocol. All patients will be followed up at the designated time intervals to record various clinical and radiographic parameters. Implant success will be defined based on the criteria elucidated by Misch et al in the Pisa, Italy Consensus. A quality-of-life assessment questionnaire will also be recorded at the end of patient's follow-up to determine their acceptance of the treatment.

RESULTS

A total of 30 dental implants will be placed in patients with a nonsyndromic orofacial cleft. Obtained results will be statistically analyzed to determine the treatment outcomes and success.

CONCLUSIONS

This study will help determine the feasibility of immediately loaded dental implants in compromised bone sites such as those presented in cleft patients and will help in generating findings that can be used to fill the lacunae currently present in the holistic treatment of cleft patients.

TRIAL REGISTRATION

Clinical Trial Registry of India CTRI/2020/09/027997; http://ctri.nic.in/Clinicaltrials/showallp.php?mid1=47659&EncHid=&userName=dental%20implants.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/25244.

A User-Friendly Protocol for Mandibular Segmentation of CBCT Images for Superimposition and Internal Structure Analysis

BACKGROUND

Since cone-beam computed tomography (CBCT) technology has been widely adopted in orthodontics, multiple attempts have been made to devise techniques for mandibular segmentation and 3D superimposition. Unfortunately, as the software utilized in these methods are not specifically designed for orthodontics, complex procedures are often necessary to analyze each case. Thus, this study aimed to establish an orthodontist-friendly protocol for segmenting the mandible from CBCT images that maintains access to the internal anatomic structures.

METHODS

The "sculpting tool" in the Dolphin 3D Imaging software was used for segmentation. The segmented mandible images were saved as STL files for volume matching in the 3D Slicer to validate the repeatability of the current protocol and were exported as DICOM files for internal structure analysis and voxel-based superimposition.

RESULTS

The mandibles of all tested CBCT datasets were successfully segmented. The volume matching analysis showed high consistency between two independent segmentations for each mandible. The intraclass correlation coefficient (ICC) analysis on 20 additional CBCT mandibular segmentations further demonstrated the high consistency of the current protocol. Moreover, all of the anatomical structures for superimposition identified by the American Board of Orthodontics were found in the voxel-based superimposition, demonstrating the ability to conduct precise internal structure analyses with the segmented images.

CONCLUSION

An efficient and precise protocol to segment the mandible while retaining access to the internal structures was developed on the basis of CBCT images.

Ischial tuberosity: new donor site for bone grafts in animal cleft research

In the context of cleft repair in animal research in rat models, different areas can be used for bone grafting. The aim of the present study was to present the tuberosity of the ischium as a new donor site and to evaluate its quality in relation to an artificial alveolar cleft. Four weeks after creating experimental alveolar clefts in seven Wistar rats, the repair was performed in the now twelve-week-old male animals using bone blocks grafted from the ischial tuberosity. Two days before surgery and two as well as twenty-eight days after surgery, microCT scans were performed, and the grafted bone blocks were analyzed regarding height, width, thickness, and volume. Additionally, bone mineral density (BMD) and bone volume fraction (BV/TV) were measured in the repaired cleft. The mean bone volume of the graft was about 19.77 ± 7.77mm³. Immediately after jaw reconstruction the BMD and BV/TV were about 0.54 ± 0.05 g/cm³ and 54.9 ± 5.07% for the transplant and about 1.13 ± 0.08 g/cm³ and 94.5 ± 3.70%, respectively, for the surrounding bone. Four weeks later the BMD and BV/TV were about 0.57 ± 0.13 g/cm³ and 56.60 ± 13.70% for the transplant and about 11.17 ± 0.07 g/cm³ and 97.50 ± 2.15%, respectively, for the surrounding bone. A hip fracture was found in four of the animals after surgery. The ischial tuberosity offers large bone blocks, which are sufficient for cleft repair in the rat model. However, the bone quality regarding BMD and BV/TV is less compared with the surrounding bone of the alveolar cleft, even after a period of 4 weeks, despite recognizable renovation processes.

Comparison of early and conventional autogenous secondary alveolar bone graft in children with cleft lip and palate: A systematic review

PURPOSE

The literature is scarce on studies comparing secondary alveolar bone graft (SABG) performed early at approximately 5-6 years and at the conventional time at 9-11 years. This systematic literature review(SLR) aimed to compare clinical outcomes after two different timings of SABG in children with unilateral and bilateral cleft lip and palate.

METHODS

The inclusion criteria were autogenous iliac grafts and the following study designs: case control, cohort, clinical controlled trial (CCT), randomized CCT (RCCT), and previous SLRs. Ovid MEDLINE, Ovid EMBASE, Web of Science, Scopus, Cochrane, ProQuest and Google Scholar were the primary databases. Two calibrated examiners worked independently to select the articles. The MINORS evaluation method for surgical non-RCTs was used to assess for quality.

RESULTS

1,111 articles were retrieved and 19 qualified. Different clinical and radiographic outcomes such as bone level, periodontal status, canine eruption and cleft-side tooth survival were evaluated by different assessment methods such as CBCT volume, computed tomography, periodontal evaluation, panoramic, intraoral radiographs, and Bergland scale. No RCCT or meta-analysis was found. None of the studies received the ideal score, which is 16 for non-comparison studies and 24 for comparison studies.

CONCLUSION

Methodological variation, lack of standardization for initial cleft dimension and low-quality level rendered a fair comparison unfeasible. Although further studies are necessary, it can be assumed that early SABG also can be an acceptable option, but this was based on a single study with a reasonable level of evidence.

Treating severe periodontitis with staged load applied implant restoration: A case report

BACKGROUND

Because immediate implant surgery is not recommended for patients who have been diagnosed with periodontitis, researchers have treated these patients with a variety of methods, including combining orthodontic and periodontal surgeries as well as implantation. However, these treatments cost time and money for the patient. Although it has been reported that temporary implants released a severe gag reflex in 1 case, only a few studies have documented using temporary implants to treat patients diagnosed with severe periodontitis.

CASE SUMMARY

The patient was a 49-year-old female who was missing the majority of her teeth and had gingival atrophy and severe alveolar bone atrophy. After being diagnosed with severe periodontitis, the patient underwent staged load applied implant restoration therapy. The first load-bearing stage was carried out immediately by inserting temporary Osstem mini implants. Maxillary teeth were extracted by using the guided bone regeneration technique, and lateral maxillary sinus lifting was conducted on both sides. During the second load-bearing stage, temporary implants were removed, and permanent implants were placed. The resin bridge was segmented during the third load-bearing stage. During the fourth load-bearing stage, the permanent prosthesis was positioned in the patient’s mouth.

CONCLUSION

By conducting the load-bearing treatment in stages, the patient’s mouth contained restorations throughout the procedure, thus guaranteeing basic function and appearance.

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

OBJECTIVES

To systematically review the existing literature on the three-dimensional (3D) radiological evaluation of secondary alveolar bone grafting (SABG) in cleft lip and palate (CLP) patients, with specific interest in 3D imaging protocols and assessment methods.

METHODS

A comprehensive literature search on PubMed, Embase and the Cochrane Library was conducted. Included publications concerned 3D imaging for evaluation of SABG in CLP patients while articles about primary or tertiary bone grafting or using of two-dimensional images only were excluded. Study quality was evaluated using the Methodological Index for Non-Randomized Studies  or the Cochrane Collaboration tool for assessing risk of bias.

RESULTS

The search yielded 1735 citations, of which 38 met the inclusion criteria. We noticed a large variability in imaging protocols and bone graft evaluation methods between studies. Most articles were observational studies with medium to low methodological quality, except for the one randomised clinical trial having a low risk of bias.

CONCLUSIONS

There is a lack of prospective, controlled trials based on a consistent imaging protocol with a sufficiently long follow-up period. A pressing need exists for the development of a consistent optimized imaging protocol for diagnosis and follow up of SABG in CLP patients. Although 3D evaluation methods seem to be more precise than two-dimensional methods, we should be careful when comparing the outcomes arising from different 3D measuring techniques.

Analyzing the teeth next to the alveolar cleft: Examination and treatment proposal prior to bone grafting based on three-dimensional versus two-dimensional diagnosis-A diagnostic study

PURPOSE

The objective was to evaluate the diagnostic and prognostic value of three-dimensional (3D) cone beam computed tomography (CBCT) on information about the cleft and alignment of cleft neighboring teeth.

MATERIALS AND METHODS

Panoramic X-rays, small-volume CBCTs, and study casts of 20 patients with a total of 22 alveolar clefts were analyzed prior to secondary bone grafting. Six maxillofacial surgeons and 6 orthodontists rated the following parameters: visibility of alveolar cleft expansion, position and probability of alignment of cleft neighbored teeth. Two-dimensional (2D) X-rays and casts were rated first; CBCT and casts followed at least 4 weeks later. Radiologic bone height in the region of the former alveolar cleft, as well as alignment and reasons for nonalignment of cleft neighbored teeth, were recorded 4 years later.

RESULTS

The rate of proper proposals regarding the real treatment outcome using 2D- or 3D-material did not differ statistically. Although 5%-45% of the proposals were changed when using 3D instead of 2D records, Fleiss multirater kappas showed no essential differences. Raters' profession and experience had no influence on the rate of correct proposals.

CONCLUSION

In orthodontics, small-volume CBCT may be justified only as supplement to a routine panoramic X-ray, and only in selected cases or for surgical preparation.

[Application of team approach and key techniques of cleft lip and palate]

The development of an expert consensus based on specific domestic situations will provide practical guidance to the efforts aiming at improving cleft care in China. The team approach of twenty-one cleft centers were pooled together, covering pre-surgical orthopedics, primary surgical repair, orthodontic treatment, alveolar bone graft, secondary deformity correction, palatal fistulae repair, the diagnosis and treatment of velopharyngeal incompetence, speech therapy, otitis media management, and skeletal deformity correction. Agreement was achieved among the authors concerning the application of critical surgical and non-surgical techniques. The ambition of this consensus is to introduce more clinicians to the revolution of sequential treatment of clefts, and form the basis for a more comprehensive cleft care manual in the future.

Conditions and calibration to obtain comparable grey values between different clinical cone beam computed tomography scanners

OBJECTIVES

The objective of the present study was to examine the grey value parameters and their magnitudes produced by CBCT and whether they are influenced by different scanners with various scanning conditions.

METHODS

An ATOM Max dental and diagnostic artificial head was scanned by two CBCT scanners (Planmeca and iCAT). Under full field of view with normal dose and ultralow-dose (ULD) conditions, the Planmeca scanner was examined for three scanning resolutions (200, 400, and 600 micron voxel sizes) and the iCAT scanner was tested for four scanning resolutions (200, 250, 300 and 400 micron voxel sizes). After 9 weeks, the artificial head was scanned again by the Planmeca scanner with the same scanning conditions. In addition, two hydroxyapatite phantoms (1220 and 1540 mg cm^-3) were adhered on the artificial head and scanned using normal and ULD scanning conditions of 400 micron voxel size with both scanners. The grey value histogram of each region, which is proportional to the bone mineral density (BMD) histogram, was utilized to determine grey value distribution parameters and compare scanners (ANOVA, p < 0.05).

RESULTS

The different scanning conditions and the bilateral locations of the artificial head did not have significant effects on measurements of the grey value parameters (p > 0.436) with excellent repeatability. However, the iCAT scanner produced significantly different grey values from the Planmeca scanner (p < 0.001).

CONCLUSIONS

CBCT can assess BMD, while calibration of absolute measures is necessary to obtain comparable values between different scanners that are currently used to assess oral bone quantity and quality.

Osteogenesis effect of guided bone regeneration combined with alveolar cleft grafting: assessment by cone beam computed tomography

Cone beam computed tomography (CBCT) allows for a significantly lower radiation dose than conventional computed tomography (CT) scans and provides accurate images of the alveolar cleft area. The osteogenic effect of guided bone regeneration (GBR) vs. conventional alveolar bone grafting alone for alveolar cleft defects was evaluated in this study. Sixty alveolar cleft patients were divided randomly into two groups. One group underwent GBR using acellular dermal matrix film combined with alveolar bone grafting using iliac crest bone grafts (GBR group), while the other group underwent alveolar bone grafting only (non-GBR group). CBCT images were obtained at 1 week and at 3 months following the procedure. Using Simplant 11.04 software, the bone resorption rate was calculated and compared between the two groups. The bone resorption rate from 1 week to 3 months following bone grafting without the GBR technique was 36.50±5.04%, whereas the bone resorption rate using the GBR technique was 31.69±5.50% (P=0.017). The application of autogenous iliac bone combined with the GBR technique for alveolar bone grafting of alveolar cleft patients can reduce bone resorption and result in better osteogenesis.