Navigating the complexities and controversies of medication-related osteonecrosis of the jaw (MRONJ): a critical update and consensus statement.

OBJECTIVES: To provide a critical update identifying the knowledge gaps and controversies in medication-related osteonecrosis of the jaw (MRONJ) within the Belgian healthcare context and outline opportunities for improvement and research in these areas. METHODS: A literature review was performed to identify guidelines from international clinical societies in oncology or oral and maxillofacial surgery on diagnosing, preventing, and treating MRONJ. The recommendations were critically assessed in light of recent developments in the field and confronted with the clinical experience of experts. RESULTS: Despite progress in the diagnostic criteria of MRONJ, the continued need for an 8-week timeout period should be reconsidered. Furthermore, 3D imaging techniques should be introduced to improve diagnosis and staging. The staging system remains ambiguous regarding Stage 0 MRONJ, and ongoing confusion exists regarding the term non-exposed MRONJ. The prevention of MRONJ should be tailored, considering the individual patient's risk of MRONJ, frailty, and life expectancy. More research seems needed into the efficacy and safety of drug holidays, considering the risks of rebound remodeling on fractures. With renewed interest in surgical and adjunct management techniques, adequately designed clinical studies are needed to help translate trial outcomes into universally applicable treatment guidelines taking into account individual patient characteristics. CONCLUSIONS: Important knowledge gaps remain and hamper the development of clinical guidelines. Several controversies were identified where consensus is lacking, and further harmonization between stakeholders is necessary. Finally, the need for randomized controlled comparative clinical trials in MRONJ resonates harder than ever to identify the best treatment for individual patients.

Anthropometric 3D evaluation of the face in patients with sleep related breathing disorders.

PURPOSE: To evaluate craniofacial measurements on 3D-stereophotogrammetry and see if particular measurements are more typical in obstructive sleep apnea (OSA) and have a correlation with its severity. METHODS: Subjects included were adults undergoing a diagnostic polysomnography. Age, BMI, neck, abdominal and hip circumference (cm) were recorded. 3D-stereophotogrammetry was performed and landmarks were placed on the 3D-image. Different linear, angular and volume measurements were performed to gauge facial and neck anatomy. The relationship between these measurements and the severity of OSA, based on the obstructive apnea/hypopnea index (OAHI, events/h), was assessed by multiple linear regression, and adjusted for BMI and sex. RESULTS: Of 91 subjects included (61 male), mean age was 46 ± 12 years, BMI 30.1 ± 6.5 kg/m2, OAHI 19.3 ± 18.8/h. BMI was higher (p = 0.0145) in females (32.9 ± 7.7) than in males (28.6 ± 5.3). This was also true for hip circumference (118 ± 15 vs 107 ± 10, p = 0.0006), while the neck circumference was higher (p < 0.0001) in males (41 ± 4 vs 37 ± 4). The following parameters could predict the logOAHI (r2-adjusted = 0.51): sex (p < 0.0001), BMI (p = 0.0116), neck-depth/mandibular-length (p = 0.0002), mandibular-width angle (p = 0.0118), neck-depth euclidean distance/surface distance (E/S) (p = 0.0001) and the interaction terms between sex and neck-depth/mandibular-length (p = 0.0034), sex and neck-depth E/S (p = 0.0276) and BMI and neck-depth E/S (p = 0.0118). The interaction between sex and neck-depth/mandibular-length showed a steeper linear course in females. This is also true for the interaction term BMI with neck-depth E/S in patients with a higher BMI. With a same neck-depth ratio, the OAHI is larger in men. CONCLUSION: Measurements involving the width of the face and addressing the soft tissue in the upper neck were found to have a significant relation with OSA severity. We found remarkable differences between non-obese/obese subjects and between males and females.

Do Gender and Age Influence Nasal Soft Tissue Widening After Bone-Borne Transpalatal Distraction?

PURPOSE: Widening of the nasal soft tissue after transpalatal distraction (TPD) is a well-known consequence of this treatment method used to correct transverse maxillary deficiency. However, because literature is scarce about the influence of gender and age, the purpose of this study is to estimate changes in the nasal soft tissue after TPD and to measure the association of gender and age with these observed changes. METHODS: In this retrospective cohort study, patients with transverse maxillary deficiency underwent combined orthodontic-surgical treatment. Maxillary and nasal anatomical landmarks were compared using superimposed cone beam computed tomography images preoperatively and approximately 1 year postoperatively. Measurements included nasal soft tissue, nasal skeletal, and maxillary parameters. Significant differences in nasal soft tissue changes were correlated with patient gender, age, maxillary, and nasal skeletal changes using regression models. RESULTS: Ninety one patients were included of which 33 were men (36%) and 58 women (64%). Independent of the maxillary widening, the mean nasal soft tissue widening was limited to 2 mm. Nasal soft tissue expansion was 60% to 80% of the nasal skeletal width and 25% to 31% of the skeletal maxillary width. The alar nasal base increased approximately 57% more than the alar nasal width. CONCLUSIONS: Significant gender-related differences in nasal soft tissue widening were observed. Age-related differences were identified only as a trend. Small age-related and gender-related differences may not be relevant clinically since there are no established threshold values to assess a layperson's perception of nasal width variations. Technical and/or aesthetic concerns regarding TPD surgery can be addressed without patient's gender and/or age consideration.

Effect of Cleft Palate Closure Technique on Speech and Middle Ear Outcome: A Systematic Review.

PURPOSE: Otitis media with effusion and disturbed speech are highly prevalent in children after cleft palate repair. Although many techniques for palatal closure have been described, no consensus has been reached on the most effective technique for these issues. The aim of this systematic review was to provide evidence-based information related to the effectiveness of different palatal closure techniques on middle ear and speech outcomes. MATERIALS AND METHODS: A literature search in multiple electronic databases was performed: National Guidelines Clearinghouse, Trip Database, Cochrane Library, and Medline (PubMed). Potentially relevant articles were selected according to title and abstract and full-text eligibility. Then, quality control on the included articles was executed. RESULTS: Twenty-three retrospective and prospective cohort studies were included in this systematic review. These studies compared at least 2 of the following techniques: von Langenbeck palatoplasty, 2-flap palatoplasty, Veau-Wardill-Kilner V-to-Y pushback technique, Kriens intravelar veloplasty, Sommerlad technique, Furlow double-opposing Z-plasties, and the Nadjmi modification of the Furlow palatoplasty. Their outcomes on the prevalence of otitis media with effusion, number of tympanostomy tubes placed, rates of hearing loss, and speech development were compared. CONCLUSIONS: The Sommerlad and Furlow palatoplasties were associated with the lowest prevalence of otitis media with effusion and the smallest number tympanostomy tubes needed. For hearing outcomes, the Furlow palatoplasty generated the best audiometric outcome. For speech outcomes, the Sommerlad and Furlow palatoplasties were more beneficial than the 2-flap palatoplasty, the Veau-Wardill-Kilner V-to-Y pushback technique, and the von Langenbeck palatoplasty. Additional randomized controlled trials are recommended to obtain evidence that can support these findings.

Spontaneous Bone Regeneration After Closure of the Hard Palate Cleft: A Literature Review.

PURPOSE: A wide range of surgical techniques have been described for the treatment of palatal clefts. Some of these surgical procedures result in postoperative osteogenesis at the palatal fissure. The aims of this review were to discuss the current approaches to cleft palate surgery leading to spontaneous bone regeneration and to compare these different procedures. Moreover, the causes of bone regeneration, effects on maxillary growth, and factors affecting bone regeneration on the hard palate are discussed. MATERIALS AND METHODS: The selected articles were found via MEDLINE and Web of Science. The keywords for the search were "cleft palate," "bone regeneration," "palatoplasty," "reconstructive surgical procedures," and "cleft palate surgery." Studies that examined the effect of primary palatoplasty on spontaneous bone regeneration in the hard palate in children were included in this review. Four articles were analyzed in the qualitative synthesis. RESULTS: Because of differences in patient characteristics and evaluation methods, it was difficult to compare different surgical procedures. The use of a mucoperiosteal flap in combination with adequate closure of the mucosa is needed to obtain bone formation. The area with the largest amount of regenerated bone was located in the middle of the hard palate. In the literature, it was found that complete closure was considered unfavorable because of the negative effects on maxillary growth, but more studies are needed to confirm this. Of the factors that have been studied, only age turned out to be borderline relevant. CONCLUSIONS: Only a few studies with small sample sizes have been published on bone regeneration in the hard palate. More research is needed to validate these findings.

Psychological Well-being and Medical Guidance of Parents of Children With Cleft in Belgium During Feeding Problems of the Child: A Mixed Method Study.

PURPOSE: Cleft is one of the most common anomalies affecting 1 in every 500-750 newborns. Depending on the type of cleft and its size, these children may experience feeding problems immediately after birth. Cleft has consequences for the child, as well as for the parents. The aim of this study was to gain a better understanding on the factors influencing the psychological well-being of the parents. Also, the experiences of parents of children with feeding problems and the received medical guidance were studied. DESIGN AND METHODS: A mixed method convergent parallel design was used. In the quantitative study, a cross-sectional design was applied, in which parents completed 3 validated questionnaires about their psychological well-being. For the qualitative research a phenomenological design was used to conduct semi-structured interviews. Ninety parents agreed to join the quantitative study, of which 15 participated in the qualitative study as well. RESULTS: The timing of the diagnosis revealed a significant difference in the depression and stress scores, while the number of children was significant for depression, anxiety, and stress. Other parental- and child-related factors did not cause a significant difference in psychological well-being. Different opinions about medical guidance and feeding problems came up during the interviews. CONCLUSION: With these results, a recommendation toward future medical guidance can be given. The number of children and the timing of diagnosis were found to be significant variables determining the psychological well-being of the parents. All parents agreed on the need for a point of contact and an umbrella framework for a clearer guidance. Moreover, caregivers should have more knowledge about cleft and associated feeding problems.

Discrete tomography in an in vivo small animal bone study.

This study aimed at assessing the feasibility of a discrete algebraic reconstruction technique (DART) to be used in in vivo small animal bone studies. The advantage of discrete tomography is the possibility to reduce the amount of X-ray projection images, which makes scans faster and implies also a significant reduction of radiation dose, without compromising the reconstruction results. Bone studies are ideal for being performed with discrete tomography, due to the relatively small number of attenuation coefficients contained in the image [namely three: background (air), soft tissue and bone]. In this paper, a validation is made by comparing trabecular bone morphometric parameters calculated from images obtained by using DART and the commonly used standard filtered back-projection (FBP). Female rats were divided into an ovariectomized (OVX) and a sham-operated group. In vivo micro-CT scanning of the tibia was done at baseline and at 2, 4, 8 and 12 weeks after surgery. The cross-section images were reconstructed using first the full set of projection images and afterwards reducing them in number to a quarter and one-sixth (248, 62, 42 projection images, respectively). For both reconstruction methods, similar changes in morphometric parameters were observed over time: bone loss for OVX and bone growth for sham-operated rats, although for DART the actual values were systematically higher (bone volume fraction) or lower (structure model index) compared to FBP, depending on the morphometric parameter. The DART algorithm was, however, more robust when using fewer projection images, where the standard FBP reconstruction was more prone to noise, showing a significantly bigger deviation from the morphometric parameters obtained using all projection images. This study supports the use of DART as a potential alternative method to FBP in X-ray micro-CT animal studies, in particular, when the number of projections has to be drastically minimized, which directly reduces scanning time and dose.

Congenital Infiltrating Lipomatosis of the Face: Case Report With Presentation of a New Multistep Surgical Approach.

PURPOSE: This report describes the first case of congenital infiltrating lipomatosis of the face (CIL-F) that was successfully managed with 2-jaw orthognathic surgery. MATERIALS AND METHODS: The patient was followed from 4 to 18 years of age. The multistep approach used consisted of a facelift-type procedure at 12 years to improve the soft tissue profile. At 13 years, the transverse maxillary deficiency was treated with transpalatal distraction. At 14 years, the patient underwent bimaxillary orthognathic surgery with a genioplasty. RESULTS: The patient's satisfaction level was very high and remained constant during the 4-year follow up. Extraoral clinical examination showed nearly complete harmonization at the soft and hard tissue levels. There was no recurrence of hypertrophy of the bones or facial soft tissues during the 4-year follow-up. CONCLUSION: The results of this study indicate that a surgical approach for CIL-F at the soft and bony levels is possible if indicated. Orthognathic surgery can be performed and good esthetic and functional results can be achieved. To minimize the risk of recurrence, it is important to perform the treatment after the onset of puberty. This harmonization at the osseous level can greatly benefit the psychological well-being of the patient.

High-resolution 3D micro-CT imaging of breast microcalcifications: a preliminary analysis.

BACKGROUND: Detection of microcalcifications on mammograms indicates the presence of breast lesion, and the shapes of the microcalcifications as seen by conventional mammography correlates with the probability of malignancy. This preliminary study evaluated the 3D shape of breast microcalcifications using micro-computed tomography (micro-CT) and compared the findings with those obtained using anatomopathological analysis. METHODS: The study analyzed breast biopsy samples from 11 women with findings of suspicious microcalcifications on routine mammograms. The samples were imaged using a micro-CT (SkyScan 1076) at a resolution of 35 µm. Images were reconstructed using filtered back-projection and analyzed in 3D using surface rendering. The samples were subsequently analyzed by the pathology service. Reconstructed 3D images were compared with the corresponding histological slices. RESULTS: Anatomopathological analysis showed that 5 of 11 patients had ductal breast carcinoma in situ. One patient was diagnosed with invasive ductal carcinoma.Individual object analysis was performed on 597 microcalcifications. Malignant microcalcifications tended to be thinner and to have a smaller volume and surface area, while their surface area-to-volume ratio was greater than that of benign microcalcifications. The structure model index values were the same for malignant and benign microcalcifications. CONCLUSIONS: This is the first study to use micro-CT for quantitative 3D analysis of microcalcifications. This high-resolution imaging technique will be valuable for gaining a greater understanding of the morphologic characteristics of malignant and benign microcalcifications. The presence of many small microcalcifications can be an indication of malignancy. For the larger microcalcifications, 3D parameters confirmed the more irregular shape of malignant microcalcifications.

Mandibular distraction osteogenesis in children with Pierre Robin sequence: long-term analysis of teeth and jaw growth.

Treatment of children with Pierre Robin sequence (PRS) having a hypoplastic mandible and upper airway distress after birth may consist of external distraction devices. Shape anomalies of the permanent molars and positional changes due to surgery have been documented. The aim of this study is to compare the long-term effects (>5 years) on the growth pattern of PRS-patients treated with an external mandibular distraction device with no-surgery cases and to investigate the dental development or damage. A retrospective cohort study was performed. PRS-patients with and without surgery were included. A digital cephalometric analysis was made to evaluate the growth pattern of the mandible between groups as well as with normal values. Nine of 19 patients underwent an external mandibular distraction. All children were extubated after 4-5 days with no signs of respiratory distress. Screw and device loosening presented in one patient. The articular and sellar angles were significantly larger and smaller, respectively, in the Surgery group. Mandibular distraction surgery might result in a 'growth boost' compared to the No-surgery group. No significant difference in dental development was found. Mandibular distraction osteogenesis is an effective way of relieving severe upper airway obstruction.

From SPECT/CT towards absolute quantification? - the case of unilateral condylar hyperplasia of the mandible.

BACKGROUND: Unilateral condylar hyperplasia (UCH) of the mandible is a rare condition characterized by asymmetric growth of the mandibular condyles. Bone scintigraphy with SPECT(/CT) is commonly used to diagnose UCH and guide treatment. Still, varying results have been reported using the traditional threshold of 55%:45% in relative tracer uptake. While absolute quantification of uptake on SPECT/CT could improve results, optimal correction and reconstruction settings are currently unknown. METHODS: Three anthropomorphic phantoms representing UCH were developed from patient CT volumes and produced using 3D printing technology. Fillable spherical inserts of different sizes (Ø: 8-15 mm) were placed in the condylar positions representing symmetrical and asymmetrical distributions. Recovery coefficients were determined for SPECT/CT using various reconstruction corrections, including attenuation and scatter correction (ACSC), resolution modeling (RM), and partial volume correction (PVC) using phantom measurements. Uptake ratios between condyles and condyle to clivus were evaluated. Finally, the impact of these correction techniques on absolute activity and diagnostic accuracy was assessed in a retrospective patient cohort for the diagnostic threshold of 55%:45%. RESULTS: The activity was only partially recovered in all spherical inserts (range: 22.5-64.9%). However, RM improved relative recovery by 20.2-62.3% compared to ACSC. In the symmetric phantoms, the 95% confidence interval (CI) of condyle ratios included the diagnostic threshold (57.6%:42.4%) for UCH when using ACSC potentially leading to false positives, but not for ACSCRM datasets. Partial volume corrections coefficients from the NEMA IQ phantom was positionally dependent, with improvements seen performing PVC using coefficients derived from anthropomorphic phantoms. Retrospective application in a patient cohort showed only a weak linear correlation (R²: 0.25-0.67) and large limits of agreement (9.6-12.5%) between different reconstructions. Up to 44% of patients were reclassified using the 55%:45% threshold. Using clinical outcome data, ACSCRM had highest sensitivity (91%; 95% CI 59-100%) and specificity (66%; 95% CI 47-81%), significantly improving specificity (P = 0.038). CONCLUSIONS: Anthropomorphic phantoms were shown to be essential in determining optimal settings for acquisition, reconstruction, and analysis. SPECT/CT reconstructions with attenuation and scatter correction and resolution modeling are recommended and could improve specificity when using the 55%:45% threshold to assess condylar growth.

Silicosis as an unusual cause of symptomatic cervical adenopathy.

A case of symptomatic cervical adenopathy is reported as a presentation of silicosis. Silicosis is one of the most important occupational health diseases worldwide caused by the inhalation of airborne silica particles. The presence of thoracic adenopathies is a common clinical feature of silicosis, cervical silicotic adenopathies on the other hand are rare and unknown to most clinicians and can therefore lead to a differential diagnostic problem. Awareness of the clinical, radiological, and histological features is key for the diagnosis.

The influence of tissue redraping after Le Fort I type osteotomy.

Elongation of the upper lip, in particular the philtrum, and nose widening are common postoperative changes after a Le Fort I osteotomy. These changes can be induced by the transection of soft tissue and loosening of the underlying musculature. A methodology for soft tissue redraping was developed to limit these undesirable nasolabial changes. This study evaluates the effectiveness of the technique and influence of maxillary translocation on the nasolabial form. Anthropometric measurements, lip, philtrum length, and nose width, were taken two weeks prior to, and one year after, surgery. The mean postoperative changes were minimised to less than 1mm except for lip length in the extrusion groups, which was less than 1.5mm. Statistical analysis showed a stable result for lip length after maxillary advancement and/or intrusion as limited lengthening mainly occurred at the vermilion. Conversely, lip lengthening after extrusion mainly occurred at the philtrum. The mean nose width was maintained after maxillary advancement, decreased after extrusion, and increased after intrusion. The type of maxillary translocation only influenced the nasolabial soft tissue in case of intrusion and extrusion, not after advancement.

A Novel Technique for Nasal Alar Reconstruction.

Reconstruction of full-thickness alar defects is delicate. Small asymmetries are visible because of the central position of the nose. Different alar reconstruction techniques such as the nasolabial, bilobed, and composite grafts provide an excellent option to reconstruct alar skin and texture. However, these donor tissues will never perfectly match alar tissue in terms of color and contour. This report presents a case of a 56-year-old woman with alar asymmetry due to soft tissue loss of the right alar rim, para-nasal, and nasolabial groove as consequence of a severe trauma in the past. Scarring tissue, retractions, and suboptimal tissue quality on the right side of the face complicated a standard procedure. In this case, a novel reconstruction technique was planned for alar reconstruction. In a two-staged procedure, a well-perfused alar base flap from the contralateral side was raised to recreate the basal portion of the right lateral alar rim. Concomitantly a lip lifting procedure was performed to correct the inadequate incisal show. As result, perfectly matching skin color, texture, and correction toward alar and facial symmetry were realized. Satisfactory aesthetic outcome for the patient was achieved. The final result was evaluated 12 months postoperatively by the use of stereophotogrammetry technology.

Impact of surgically assisted rapid mandibular expansion on the temporomandibular joint - A retrospective study.

This study evaluates the impact of tooth-borne Surgically Assisted Rapid Mandibular Expansion (SARME) on the temporomandibular joint (TMJ) function and condylar morphology. Medical records of patients who received a SARME between 2014 and 2018 are retrospectively reviewed concerning functional problems. Morphological changes of the condyles are analyzed by means of surface registration of 3D reconstructed CBCT scans preoperatively and one-year postoperatively, and correlated to functional outcome. In 68 patients data are complete. The risk of TMJ dysfunction is slightly increased from 18 to 25% at a mean of 14 months after SARME. This is attributed to an increase in the number of minor problems (75-82%). The presence of complaints before SARME is the only identifiable risk factor for also having complaints after the intervention (p = 0.0019). In one patient with pre-existent TMJ dysfunction complaints deteriorated after SARME. After SARME no cases of extended condylar resorption are described. There is no correlation between morphological condylar changes and the prevalence of TMJ dysfunction (p = 0.7121 for appositional and p = 0.3038 for resorptive changes). However, appositional and resorptive changes at the condylar head appear to correlate with growth potential, based on age, gender and skeletal deformity (p < 0.0001 and p = 0.0154 respectively). Within the limitations of the study it seems that SARME does not have a negative impact on TMJ function or condylar integrity and, therefore, the choice for or against this approach can be made without considering consequences for TMJ a major issue for the decision.

Virtual planning in Le Fort III distraction osteogenesis: A case series.

The objective of this study is to determine the value of using 3D planning tools and 3D printed cutting guides in Le Fort III osteotomies with external frame distraction osteogenesis. The process of planning and transfer of the virtual planning to the operating room is illustrated with 5 case. The virtual planning is transferred to the operating room using a 3D-printed supra-orbital reference bar with puzzle connections for the planned osteotomy guides. Different systems are presented to transfer the vector of distraction and the position of the external midface distractor. Three-dimensional planning tools and cutting guides help to design the Le Fort III osteotomy and the distraction vector, to anticipate possible difficulties, and to avoid adverse events.

Investigating morphological changes in treated vs. untreated stone building materials by x-ray micro-CT.

Calcareous stones have been largely used to build historical buildings. Among these, the calcarenites are usually characterized by a high content of calcite and a high open porosity, which make them very sensitive to the weathering caused by physical and chemical agents. In order to prevent their deterioration and to retard their decay, different protective products-mainly polymers-are applied on the stone artefact surfaces. In this work we apply the methodology tested in a preliminary study to investigate the morphological changes of the internal structure of a biocalcarenite (Lecce stone) by micro x-ray computed tomography (micro-CT). The porosity and other morphological parameters of the rock before and after the conservation treatment were calculated on a significant number of samples. The Student's t test was applied for statistical comparison. The results reveal that the treatment with Paraloid B72 (PB 72) is homogenously distributed and causes small changes to the natural properties of the rock, whereas the application of a fluoroelastomer (NH) causes an appreciable decrease in porosity and variation in terms of wall thickness distribution, probably resulting from its inhomogeneous distribution.

Evaluation of Dimensional Changes of 3D Printed Models After Sterilization: A Pilot Study.

OBJECTIVES: To assess the effect of two of the most commonly used sterilization techniques on 3D printed clinical objects. MATERIALS & METHODS: The two sterilization methods used in our hospital and investigated in this paper are: Steam heat and Gas plasma. Three objects were printed and tested in this study: a tooth replica, an orthognathic final splint, a surgical cutting guide for the purpose of mandible reconstruction. For each of the 3 objects, 4 copies were made: one original STL object, one copy of the object pre-sterilization, one copy of post-steam heat sterilization, and one copy of post-gas plasma sterilization. Each printed object was scanned using a high resolution CBCT protocol and the compared (morphologically and volumetrically). RESULTS: At the level of volumetric changes, no difference was found between pre and post-sterilization for both methods evaluated. As for the morphological changes, only differences were noticed with the orthognathic splint object indicating deformation of the printed splints after sterilization. Larger differences were observed with heat sterilization, making it less reliable. CONCLUSION: Sterilization of dental objects to be used in a clinical setting may lead to deformation of the printed model, especially for heat sterilization. Further investigations are needed to confirm these findings.

Minimally Invasive Genioplasty Procedure.

In this technical note, we present a new surgical approach for genioplasty in which a minimally invasive procedure is used to perform the chin osteotomy. The main goal was to reduce postoperative functional recovery time and possible complications, especially reduction of lip incompetence, chin ptosis, and muscle dysfunction, by retaining the intactness of the mentalis muscles.

Accuracy of segmentation of tooth structures using 3 different CBCT machines.

OBJECTIVE: The aim of this study was to evaluate the volumetric accuracy and reliability of cone beam computed tomography (CBCT)-based tooth segmentation using 4 different CBCT exposure protocols. METHODS: Two dry, intact adult human mandibles of unknown gender were scanned using 4 different CBCT exposure protocols (3 CBCT systems). The available mandibular premolars (3 per mandible) were segmented, resulting in a total of 24 segmented teeth. To assess the accuracy of the segmented teeth, volumetric and morphologic differences between the real anatomic teeth and the reconstructed images were evaluated both physically and using a high-resolution micro-computed tomography system. RESULTS: Results revealed a high accuracy of CBCT reconstructed images when comparing volumetric measures of CBCT-based segmented premolars to physical measurements of corresponding physical teeth. Volumetric differences were below 2%. Morphologic differences using the segmented model and the corresponding micro-computed tomography scans of the physical teeth indicated that when inaccuracies occurred, they were at the apical and coronal parts of the tooth. CONCLUSION: Based on these results, CBCT can be used as a tool for segmentation and pretherapeutic planning procedures.