Spray and stretch technique and its effects on mouth opening.

STATEMENT OF PROBLEM: Mandibular mouth opening through passive stretching may be an awkward and painful experience for patients with orofacial pain. Whether a spray technique would reduce such discomfort is unclear. PURPOSE: The purpose of this clinical study was to determine whether the use of a spray technique would be an effective method of increasing maximal mouth opening (MMO) without passive stretching to avoid patient discomfort. MATERIAL AND METHODS: A sample of 61 participants, 33 men and 28 women, without orofacial pain was selected from a general dental office, and a sample of 60 participants, 30 men and 30 women, was selected from a cohort of over 750 patients with orofacial pain from an oral surgery department. The presence of orofacial pain in the patient group was verified and recorded by means of palpation of the temporomandibular joints (TMJs) and masticatory, neck, and shoulder muscles. All participants in the study were instructed to open their mouth maximally to permit insertion of a TMJ equilateral triangle and the measurement of their MMO twice. Then, the participants were informed that a vapocoolant would be sprayed twice on both cheeks from the mandibular angle to the temple area. After spraying, the participants were requested to open their mouth maximally, and again the interincisal distance was measured twice. For analysis of the variables, a 2-way ANOVA was used with estimates for group effects and a correction for sex. A covariance model was used to test the effect of age (α=.05). RESULTS: Testing for age revealed an effect for both study groups (P=.032), but not for sex (P=.074). Testing baseline values of maximal mouth opening for the studied groups revealed no significant difference (P=.175), although for sex, it did (P=.008). The relative gain as a percentage of increase in mouth opening led to similar results, comparable with the values of the absolute increase in magnitude (P<.001 for the study groups and P=.090 for sex). Testing the effect of age in a covariance model did not lead to a significant result (P=.73). CONCLUSIONS: The spray and stretch technique increased maximal mouth opening in most participants, more so in participants with orofacial pain than in the control group and more in women than in men. Pain from passive stretching can be prevented.

Cathepsin K associates with lymph node metastasis and poor prognosis in oral squamous cell carcinoma.

BACKGROUND: Lymph node metastasis (LNM) is a major determinant of prognosis and treatment planning of oral squamous cell carcinoma (OSCC). Cysteine cathepsins constitute a family of proteolytic enzymes with known role in the degradation of the extracellular matrix. Involvement in pathological processes, such as inflammation and cancer progression, has been proved. The aim of the study was to discover the clinicopathological and prognostic implications of cathepsin K (CTSK) expression in oral squamous cell carcinoma. METHODS: Eighty-three patients with primary OSCC, treated surgically between 1996 and 2000, were included. Gene expression data were acquired from a previously reported study. Human papilloma virus (HPV) status was previously determined by an algorithm for HPV-16. CTSK Protein expression was semi-quantitatively determined by immunohistochemistry in tumor and stromal cells. Expression data were correlated with various clinicopathological variables. RESULTS: Elevated gene and protein expression of CTSK were strongly associated to LNM and perineural invasion (p < 0.01). Logistic regression analysis highlighted increased CTSK protein expression in tumor cells as the most significant independent factor of lymphatic metastasis (OR = 7.65, CI:2.31-23.31, p = 0.001). Survival analysis demonstrated CTSK protein expression in both stromal and tumor cells as significant indicators of poor 5-year disease specific survival (HR = 2.40, CI:1.05-5.50, p = 0.038 for stromal cells; HR = 2.79, CI:1.02-7.64, p = 0.045 for tumor cells). CONCLUSION: Upregulation of CTSK seems to be associated with high incidence of lymphatic spread and poor survival in OSCC. CTSK could therefore serve as a predictive biomarker for OSCC.

A novel semi-automatic segmentation protocol for volumetric assessment of alveolar cleft grafting procedures.

A novel protocol for volumetric assessment of alveolar cleft grafting procedures is presented. Eleven cone-beam computed tomography (CBCT) datasets of patients who underwent secondary alveolar cleft reconstructive surgery for a unilateral alveolar cleft were evaluated by two investigators. Residual bone volumes 1 year after surgery were analysed using a semi-automated technique in which preoperative CBCT datasets were superimposed on the postoperative scans using voxel-based registration. To define the correct boundaries of the alveolar cleft defect in the preoperative CBCT dataset, a mirror image of the preoperative CBCT dataset was superimposed on the preoperative CBCT dataset. For the difference in residual bone volume between the two observers, an intraclass correlation of 0.98 and a Dice coefficient of 0.89 were found. This study describes a reliable segmentation protocol for volumetric analysis of the alveolar cleft defect in patients with a unilateral alveolar cleft.

Microstructured ß-Tricalcium Phosphate Putty Versus Autologous Bone for Repair of Alveolar Clefts in a Goat Model.

For the first time it was demonstrated that an osteoinductive calcium phosphate-based putty is effective in the restoration of complex maxillofacial defects. In these defects, adequate mechanical confinement by multiple bony walls and osteoconduction from multiple surfaces are usually lacking. This study compares the efficacy of a microstructured beta-tricalcium phosphate (ß-TCP) putty with autologous bone for the repair of alveolar cleft defects. A total of 10 Dutch milk goats were operated on in a split-mouth study design in which two-wall bony alveolar clefts were created and successively repaired with autologous bone (the gold standard) at one side and ß-TCP putty at the other. After 24 weeks of implantation, histomorphometric and micro-computer tomography analyses proved that the ß-TCP putty group showed equal bone quality and volume to clefts reconstructed with autologous bone. In addition, surgical handling of the putty is superior to the use of calcium phosphates in a granular form. Therefore, the results of this study open a clear trajectory for the clinical use of ß-TCP putty in the reconstruction of the alveolar cleft and other challenging two-wall bony defects.

Amplification and protein overexpression of cyclin D1: Predictor of occult nodal metastasis in early oral cancer.

BACKGROUND: Accurate nodal staging is pivotal for treatment planning in early (stage I-II) oral cancer. Unfortunately, current imaging modalities lack sensitivity to detect occult nodal metastases. Chromosomal region 11q13, including genes CCND1, Fas-associated death domain (FADD), and CTTN, is often amplified in oral cancer with nodal metastases. However, evidence in predicting occult nodal metastases is limited. METHODS: In 158 patients with early tongue and floor of mouth (FOM) squamous cell carcinomas, both CCND1 amplification and cyclin D1, FADD, and cortactin protein expression were correlated with occult nodal metastases. RESULTS: CCND1 amplification and cyclin D1 expression correlated with occult nodal metastases. Cyclin D1 expression was validated in an independent multicenter cohort, confirming the correlation with occult nodal metastases in early FOM cancers. CONCLUSION: Cyclin D1 is a predictive biomarker for occult nodal metastases in early FOM cancers. Prospective research on biopsy material should confirm these results before implementing its use in routine clinical practice. © 2016 Wiley Periodicals, Inc. Head Neck 39: 326-333, 2017.

Surgical treatment of unilateral zygomaticomaxillary complex fractures: A 7-year observational study assessing treatment outcome in 153 cases.

This study investigates treatment outcome in zygomaticomaxillary complex (ZMC) fracture repair. METHODS: The medical records and CT-images of patients that received treatment for a unilateral ZMC fracture in 2005-2011 were studied. ZMC fractures were categorised as incomplete (type A), tetrapod (type B) or comminuted (type C). The incidence of sequelae, wound infection and secondary surgical interventions was analysed per fracture category. RESULTS: A total of 153 patients were treated in the selected period. Persisting sensory disturbances in the area innervated by the infraorbital nerve were observed in 50 cases (37%), facial asymmetry in 19 cases (14%), enophthalmos in 10 cases (7%) and persisting diplopia in 9 cases (7%). Wound infection occurred in 6 cases (4%). Secondary surgical procedures of the ZMC, orbital floor, and/or extraocular muscles were performed in 14 cases (9%). C-type fractures were associated with more secondary corrections for ZMC malreduction (12%, p = 0.03), more secondary reconstructions of the orbital floor (10%, p < 0.01), and more functional corrections of diplopia by extraocular muscle correction (5%, p = 0.02). CONCLUSION: Treatment outcome in C-type ZMC fractures is less favourable than treatment outcome in A-type and B-type fractures. Intraoperative imaging, surgical navigation devices and 3D-planning software may improve treatment outcome in C-type ZMC fractures.

Clinical relevance of copy number profiling in oral and oropharyngeal squamous cell carcinoma.

Current conventional treatment modalities in head and neck squamous cell carcinoma (HNSCC) are nonselective and have shown to cause serious side effects. Unraveling the molecular profiles of head and neck cancer may enable promising clinical applications that pave the road for personalized cancer treatment. We examined copy number status in 36 common oncogenes and tumor suppressor genes in a cohort of 191 oropharyngeal squamous cell carcinomas (OPSCC) and 164 oral cavity squamous cell carcinomas (OSCC) using multiplex ligation probe amplification. Copy number status was correlated with human papillomavirus (HPV) status in OPSCC, with occult lymph node status in OSCC and with patient survival. The 11q13 region showed gain or amplifications in 59% of HPV-negative OPSCC, whereas this amplification was almost absent in HPV-positive OPSCC. Additionally, in clinically lymph node-negative OSCC (Stage I-II), gain of the 11q13 region was significantly correlated with occult lymph node metastases with a negative predictive value of 81%. Multivariate survival analysis revealed a significantly decreased disease-free survival in both HPV-negative and HPV-positive OPSCC with a gain of Wnt-induced secreted protein-1. Gain of CCND1 showed to be an independent predictor for worse survival in OSCC. These results show that copy number aberrations, mainly of the 11q13 region, may be important predictors and prognosticators which allow for stratifying patients for personalized treatment of HNSCC.

Tooth loss prior to radiation in relation to tumor location in patients with head and neck cancer.

PURPOSE: This study aimed to investigate the impact of preradiation tooth loss in patients with head and neck cancer. MATERIALS AND METHODS: Records of 397 (partially) dentate patients who were referred for preradiation oral screening were included. Number and location of teeth lost and occluding pairs lost were determined for different tumor locations. RESULTS: The majority of patients (54%) were affected by tooth loss. Proportion of teeth lost, their location, and proportion of occluding pairs lost were not evenly distributed across tumor locations. The highest proportions of teeth were removed with oral tumors (maxilla: 25%; mandible: 47%). For preradiation preventive extractions only, ie, not taking into account teeth that were lost due to ablative surgery, tooth loss in the mandible was still not evenly distributed across tumor locations, but tooth loss in the maxilla and occluding pairs lost were. CONCLUSIONS: Tumor location affects preradiation tooth loss, though this is primarily a consequence of ablative surgery rather than a consequence of preradiation dental extraction decisions. Since patients with oral cavity tumors are affected most by preradiation tooth loss, treatment planning with regard to functional rehabilitation is desirable for this patient group in particular.

Intraoperative imaging for the repair of zygomaticomaxillary complex fractures: a comprehensive review of the literature.

INTRODUCTION: Intraoperative imaging seems to be the next step to improve surgical outcome in the treatment of zygomaticomaxillary complex (ZMC) fractures. Many publications have appeared on intraoperative imaging for trauma surgery, but in most hospitals intraoperative imaging is not routinely performed for ZMC fracture repair. The goal of this review was to assess the value of intraoperative imaging in ZMC fracture repair. MATERIAL AND METHODS: The literature was reviewed with focus on the effects of intraoperative imaging on facial symmetry, fracture reduction and the frequency of additional reduction after intraoperative imaging in ZMC fractures. RESULTS: Six publications were found on the frequency of additional reduction after intraoperative imaging in ZMC fracture repair. Revision of the reduction of the zygoma was performed in 18% (95% CI 10.5%-29.0%), revision of the orbital floor was performed in 9% (95% CI 3.6%-17.2%). No publications were found on the effects of intraoperative imaging on facial symmetry or on the accuracy of fracture reduction. CONCLUSIONS: Information obtained from intraoperative imaging often has consequences on the surgical management of ZMC fractures. However, the effect on restoration of facial symmetry and fracture reduction is yet to be established.

Promoter hypermethylation using 24-gene array in early head and neck cancer: better outcome in oral than in oropharyngeal cancer.

Silencing of tumor suppressor genes (TSGs) by DNA promoter hypermethylation is an early event in carcinogenesis and a potential target for personalized cancer treatment. In head and neck cancer, little is known about the role of promoter hypermethylation in survival. Using methylation specific multiplex ligation-dependent probe amplification (MS-MLPA) we investigated the role of promoter hypermethylation of 24 well-described genes (some of which are classic TSGs), which are frequently methylated in different cancer types, in 166 HPV-negative early oral squamous cell carcinomas (OSCC), and 51 HPV-negative early oropharyngeal squamous cell carcinomas (OPSCC) in relation to clinicopathological features and survival. Early OSCC showed frequent promoter hypermethylation in RARB (31% of cases), CHFR (20%), CDH13 (13%), DAPK1 (12%), and APC (10%). More hypermethylation (≥ 2 genes) independently correlated with improved disease specific survival (hazard ratio 0.17, P = 0.014) in early OSCC and could therefore be used as prognostic biomarker. Early OPSCCs showed more hypermethylation of CDH13 (58%), TP73 (14%), and total hypermethylated genes. Hypermethylation of two or more genes has a significantly different effect on survival in OPSCC compared with OSCC, with a trend toward worse instead of better survival. This could have a biological explanation, which deserves further investigation and could possibly lead to more stratified treatment in the future.

Tissue engineering strategies for alveolar cleft reconstruction: a systematic review of the literature.

OBJECTIVES: To date, a great number of tissue engineering strategies have been suggested for alveolar cleft reconstruction; however, autologous bone grafting seems to remain the golden standard. MATERIALS AND METHODS: A systematic review of the literature was conducted in order to evaluate the clinical evidence pertaining to enhancement or replacement of the autologous bone graft in the alveolar cleft by means of tissue-engineered substitutes; 16 articles were selected for analysis. RESULTS: Tissue engineering strategies for alveolar cleft grafting included enhancing the autologous bone graft by means of platelet-rich plasma addition, the use of barrier membranes and fibrin glue, extension of the autologous graft with calcium phosphate scaffolds, and replacement of the graft using bone morphogenetic protein-2, mesenchymal stem cells, or calcium phosphate scaffolds. CONCLUSIONS: Selected articles showed a vast heterogeneity in data acquisition and patient selection. Therefore, a meta-analysis could not be performed. Future publications concerning this topic should be methodologically sound and preferably use three-dimensional radiological imaging for pre- and postoperative results. CLINICAL RELEVANCE: Bypassing or enhancing autologous bone grafting by means of tissue engineering solutions has become an important topic in alveolar cleft grafting. Replacement of the autologous bone graft will result in absence of donor site morbidity in this predominantly young population.

Cannabinoid receptor-2 immunoreactivity is associated with survival in squamous cell carcinoma of the head and neck.

The prediction of progression of individual tumours, prognosis, and survival in squamous cell carcinoma (SCC) of the head and neck is difficult. Cannabinoid-1 (CB1) and cannabinoid-2 (CB2) receptor expression is related to survival in several types of cancer, and the aim of this study was to find out whether the expression of CB1 and CB2 receptors is associated with survival in primary SCC of the head and neck. We made immunohistochemical analyses of the cannabinoid receptors on tissue arrays from 240 patients with the disease. Receptor immunoreactivity was classified as none, weak, moderate, or strong staining. Overall survival and disease-specific survival were plotted using Kaplan-Meier survival curves. A multivariate Cox proportional hazard model was created with all the relevant clinical and pathological features. Strong immunoreactivity of the CB2 receptor was significantly associated with reduced disease-specific survival (p=0.007). Cox-proportional hazard ratio (HR) showed that CB2 receptor immunoreactivity contributed to the prediction of survival (HR 3.6, 95% CI 1.5-8.7, p=0.004). Depth of invasion (HR 2.2, 95% CI 1.2-4.2, p=0.01) and vascular invasion (HR 2.5, 95% CI 1.4-4.5, p=0.001) were also associated with survival.

Donor-site morbidity of the radial forearm free flap versus the ulnar forearm free flap.

BACKGROUND: Donor-site morbidity following harvest of the radial forearm free flap was compared with that following harvest of the ulnar forearm free flap. METHODS: Twenty-eight radial forearm and 27 ulnar forearm flaps were harvested in 55 patients with head and neck defects. Pressure perception was measured with Semmes-Weinstein monofilaments. Cold perception was tested with chloroethyl. Donor-site healing was evaluated. Patients were interviewed about grip and pinch strength and donor-site appearance. RESULTS: In the radial forearm free flap group, pressure perception and cold perception were reduced in the donor hand, whereas in the ulnar group, no differences were observed between the donor and unoperated hands. In the radial forearm group, 15 percent of patients experienced reduced strength in the donor hand, whereas in the ulnar forearm group, none of the patients reported reduced strength in the donor hand. In the radial forearm group, 14 percent had partial or complete loss of the skin graft, whereas in the ulnar forearm group, 4 percent had partial loss of the skin graft. In the radial forearm group, 18 percent of patients were dissatisfied with the appearance of the donor site, and no complaints were reported in the ulnar forearm group. CONCLUSIONS: The authors' study shows less donor site-morbidity following harvest of the ulnar forearm free flap than following harvest of the radial forearm free flap. These results emphasize that the ulnar forearm free flap should be considered as an alternative for the radial forearm free flap for reconstruction of soft-tissue defects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Donor site complications in bone grafting: comparison of iliac crest, calvarial, and mandibular ramus bone.

PURPOSE: To compare the donor site complication rate and length of hospital stay following the harvest of bone from the iliac crest, calvarium, or mandibular ramus. MATERIALS AND METHODS: Ninety-nine consecutively treated patients were included in this retrospective observational single-center study. RESULTS: Iliac crest bone was harvested in 55 patients, calvarial bone in 26 patients, and mandibular ramus bone in 18 patients. Harvesting of mandibular ramus bone was associated with the lowest percentages of major complications (5.6%), minor complications (22.2%), and total complications (27.8%). Harvesting of iliac crest bone was related to the highest percentages of minor complications (56.4%) and total complications (63.6%), whereas harvesting of calvarial bone induced the highest percentage of major complications (19.2%). The length of the hospital stay was significantly influenced by the choice of donor site (P = .003) and age (P = .009); young patients with the mandibular ramus as the donor site had the shortest hospital stay. CONCLUSIONS: Harvesting of mandibular ramus bone was associated with the lowest percentage of complications and the shortest hospital stay. When the amount of bone to be obtained is deemed sufficient, mandibular ramus bone should be the first choice for the reconstruction of maxillofacial defects.

An epidemiological study of maxillofacial fractures requiring surgical treatment at a tertiary trauma centre between 2005 and 2010.

The epidemiology of maxillofacial fractures shows considerable regional variation as a result of local demographic and socioeconomic factors. We have assessed the epidemiological characteristics of such fractures at our centre in The Netherlands. The medical records of 394 patients who were treated surgically for maxillofacial fractures between 1 January 2005 and 31 December 2010 were analysed retrospectively. The male:female ratio was 3:1. There was a peak incidence in the second and third decades of life among men. The number of injured patients/year remained stable during the selected period. The incidence was highest in the spring and at weekends. Fractures of the mandible and zygoma were the most common. Road traffic crashes were the most common cause of injury (42%) and mainly involved bicycles. A total of 165 (15%) of the patients were intoxicated, and 142 patients (36%) had other serious injuries. Most patients (n=248, 63%) were treated within a day of presentation. Two hundred and thirty-two patients (59%) spent 4 days or fewer in hospital. The presence of other injuries was associated with a prolonged stay in hospital. Groups at particular risk of maxillofacial fractures are young men and cyclists. The use of helmets by cyclists could achieve a large reduction in injuries to the brain and upper face.

Reconstruction of the alveolar cleft: can growth factor-aided tissue engineering replace autologous bone grafting? A literature review and systematic review of results obtained with bone morphogenetic protein-2.

The alveolar cleft in patients with clefts of lip, alveolus and palate (CLAP) is usually reconstructed with an autologous bone graft. Harvesting of autologous bone grafts is associated with more or less donor site morbidity. Donor site morbidity could be eliminated if bone is fabricated by growth factor-aided tissue engineering. The objective of this review was to provide an oversight on the current state of the art in growth factor-aided tissue engineering with regard to reconstruction of the alveolar cleft in CLAP. Medline, Embase and Central databases were searched for articles on bone morphogenetic protein 2 (BMP-2), bone morphogenetic protein 7, transforming growth factor beta, platelet-derived growth factor, insulin-like growth factor, fibroblast growth factor, vascular endothelial growth factor and platelet-rich plasma for the reconstruction of the alveolar cleft in CLAP. Two-hundred ninety-one unique search results were found. Three articles met our selection criteria. These three selected articles compared BMP-2-aided bone tissue engineering with iliac crest bone grafting by clinical and radiographic examinations. Bone quantity appeared comparable between the two methods in patients treated during the stage of mixed dentition, whereas bone quantity appeared superior in the BMP-2 group in skeletally mature patients. Favourable results with BMP-2-aided bone tissue engineering have been reported for the reconstruction of the alveolar cleft in CLAP. More studies are necessary to assess the quality of bone. Advantages are shortening of the operation time, absence of donor site morbidity, shorter hospital stay and reduction of overall cost.

ß-TCP versus autologous bone for repair of alveolar clefts in a goat model.

OBJECTIVE: The aim of this study in goats was to test the hypothesis that a novel synthetic bone substitute beta tricalcium phosphate (ß-TCP) can work as well as autologous bone harvested from the iliac crest for grafting and repair of alveolar clefts. DESIGN: Ten adult Dutch milk goats (Capra hircus) were used in a split-mouth study design. MAIN OUTCOME MEASURES: Volumetric histologic assessment of new bone formation and radiographic measurement of orthodontic movement of teeth in a formerly created alveolar cleft. CONCLUSIONS: The synthetic bone substitute ß-TCP was shown to result in bone healing similar to that of iliac crest bone. The surgical, orthodontic, and histologic results now warrant the testing of ß-TCP in the human cleft situation.

A prospective study on the effect of modified alar cinch sutures and V-Y closure versus simple closing sutures on nasolabial changes after Le Fort I intrusion and advancement osteotomies.

PURPOSE: The purpose of this study was to determine whether a modified alar cinch suture and V-Y closure (mACVY) have a beneficial effect on labial form after Le Fort I intrusion and advancement osteotomies and whether they result in excessive upward nasal tip rotation. Both are possible effects compared with simple closing sutures (SCS). PATIENTS AND METHODS: A prospective study was carried out on 56 patients, 31 with mACVY and 25 with SCS. Lateral cephalograms taken immediately before and 18 months after operation were used, measuring horizontal and vertical changes of the following landmarks: anterior and posterior nasal spine, A-point, incision superior, pronasale, subnasale, labiale superior, and stomion superior, as well as angular changes of sella-nasion-pronasale, and changes in upper vermilion exposure. Statistical analysis was performed on intragroup, paired t test, and intergroup differences, unpaired t test (P < .05). RESULTS: The horizontal and vertical changes of labiale superior were significantly larger for mACVY versus SCS, and the angle sella-nasion-pronasale increased in mACVY versus SCS. However, no significant difference was found for vertical changes of the nasal tip. Upper vermilion exposure increased with mACVY versus SCS. CONCLUSION: mACVY has a beneficial effect on labial form, and excessive upward rotation of the nasal tip is prevented.

Orthodontic treatment results following grafting autologous mandibular bone to the alveolar cleft in patients with a complete unilateral cleft.

OBJECTIVE: To analyze orthodontic treatment results following mandibular symphysis bone grafting and postoperative orthodontic treatment. DESIGN: Randomized selection of 75 patients out of 308 with unilateral cleft of lip, alveolus, and palate, operated upon according to protocol between 1990 and 2008 in the Wilhelmina Children's Hospital, Utrecht, The Netherlands. MAIN OUTCOME MEASURE: Goslon Yardstick rating changes of dental arch relationship. Significant agreement (p < .001) was observed between the two assessments carried out with an interval of 3 months (Cohen's kappa = .963, p < .001). RESULTS: Following mandibular bone grafting and orthodontic treatment in 65.3% of the patients, the aim of treatment (Goslon Yardstick groups 1 and 2) had been achieved. The applied before/after Goslon allocations showed high improvement significance (p < .001). CONCLUSIONS: Postoperative orthodontic treatment in patients following grafting with mandibular symphysis bone showed excellent results.

Bone structure changes in iliac crest grafts combined with implants.

BACKGROUND: Remodeling of onlay grafts combined with implants to the mandible results in predictable changes in the graft's radiographic density. We studied the relationship between changes in radiographic density and trabecular structure during the first year after onlay grafting with simultaneous implant placement to the mandible. PURPOSE: The aim of this study was to evaluate changes in bone structure after onlay grafting. MATERIALS AND METHODS: Standardized extraoral radiographs were taken regularly of 16 mandibular sides. Bone structure was measured using the Carl Zeiss Vision KS 400 3.0 imaging system. The parameters studied were trabecular area and perimeter, cavity area and perimeter, end points, branching points, skeleton length, branch angle and direction, and texture. RESULTS: No differences were found between measurements ventrally versus dorsally of the implant, nor close to versus away from the implant. Early cortical changes suggest partial resorption and formation of a more complex structure. In the fourth quarter after surgery, progressive resorption is seen in the graft's upper cortex. In the graft's upper spongiosa, most parameters indicate bone formation during the first postoperative year. Loading-induced structure changes could not yet be found. CONCLUSION: The technique can be used to study changes in the architecture of bone grafts. Changes found in the graft's architecture are in accordance with changes in bone density.