Mandibular Distraction Osteogenesis in Children and Adolescents: A Clinical and Radiographic Research Using Cone-Beam Computed Tomography

AIM

The aim of this cross-sectional study was to evaluate, via cone-beam computed tomography, the long-term postoperative outcome in children treated with mandibular distraction osteogenesis.

MATERIALS AND METHODS

All young patients treated with mandibular distraction osteogenesis (MDO), during a 16-year period, at the University Department of Oral and Maxillofacial Surgery of a Pediatric Hospital, were recalled, and various clinical and radiographic parameters were recorded.

RESULTS

Eleven patients were included: 5 with hemifacial microsomia (HFM) and 6 with mandibular micrognathia. In all cases, MDO had been successful in regular follow-up and decannulation, soon after MDO, was achieved in all tracheostomy cases. The long-term result in cases of HFM was found stable, functionally and esthetically accepted, although less satisfactory than in regular follow-up; in micrognathia patients, relapse of different degrees was registered in 4 of 6 cases, without any need for tracheostomy though. Detailed and accurate information was obtained by cone-beam computed tomography (CBCT). The shape of the regenerated bone was irregular in HFM cases and relatively normal in the micrognathia cases. Quality of the regenerated bone was normal in all patients. The irregular shape registered in HFM cases did not compromise a safe orthognathic operation.

CONCLUSIONS

Distraction osteogenesis remains an early treatment choice in cases of mandibular deformities. Long-term findings showed that there is a degree of relapse with growth, which was more obvious in mandibular micrognathia cases. Computed tomography contributes to detailed evaluation of changes at the distraction site.

Radiologic findings of osteonecrosis, osteoradionecrosis, osteomyelitis and jaw metastatic disease with cone beam CT

PURPOSE

The purpose of this study was to assess CBCT scans of patients with medication related osteonecrosis of the jaws (MRONJ), osteoradionecrosis (ORN), osteomyelitis (OM) and jaw metastatic disease (JM), evaluate the presence and extent of radiologic findings, identify radiologic parameters that may distinguish the four entities and last, introduce a new modified radiographic index (CRIm), in order to contribute to the diagnosis of these conditions.

METHODS

Τwo major databases were retrospectively searched for fully documented and diagnosed CBCT scans of MRONJ, ORN, OM and JM from 2006 to 2019. 335 CBCT scans met the inclusion criteria and were assessed under standardized viewing conditions blindly by 2 observers. The CRIm index proposed in this study evaluates: lytic changes, sclerosis, periosteal bone formation, sequestration, non-healing extraction sockets and other findings which included: sinus implication, inferior alveolar canal implication and jaw fracture. Lytic changes, sclerosis, periosteal bone formation, sequestration and non-healing extraction sockets were scored as: absent (0), localized/single (1) and extensive/multiple (2). Each one of other findings were scored individually as: absent (0) and present (1). For statistical analysis t-test, Pearson's r correlation coefficient, one-way ANOVA and Bonferonni were performed.

RESULTS

Extensive lytic changes were the most common finding, especially for ORN, where it occurred in all CBCT scans (100%). The mean value of the CRIm index differs significantly between CBCT scans with MRONJ and JM, as well as between those with OM and JM (Bonferroni p < 0.001).

CONCLUSIONS

The new modified Composite Radiographic Index introduced in this study, appears to have improved an objective approach to the previously used Composite Radiographic Index by means of cumulative radiologic features. Τhe predominance of certain radiologic features in one or more of these entities may lead the diagnostician towards the correct diagnosis.

Morphological Assessment of Nasopalatine Canal Using Cone Beam Computed Tomography: A Retrospective Study of 124 Consecutive Patients

This study aimed to assess and analyze the morphology and dimensions of the nasopalatine canal (NPC), as well as the adjacent buccal osseous plate (BOP), and to investigate the effect of gender, edentulism, NPC types, absence of maxillary central incisors (ACI) and age on the NPC and BOP, using cone beam computed tomography (CBCT). A total of 124 CBCT examinations (67 female and 57 male patients) were retrospectively included and evaluated. The assessment of the dimensions of the NPC, as well as the dimensions of the adjacent BOP, was performed by three Oral and Maxillofacial Radiologists on reconstructed sagittal and coronal CBCT sections under standardized conditions. Regarding the dimensions of the NPC and the adjacent BOP, the mean values were significantly higher among males than females. Furthermore, edentulous patients showed a significant reduction in BOP dimensions. Additionally, NPC types showed a significant effect on the length of the NPC, and the ACI had a significant effect on reducing BOP dimensions. Age had a significant effect on the diameter of the incisive foramen, with the mean values generally increasing with an increasing age. CBCT imaging of this anatomical structure contributes significantly to its full assessment.

The effect of nano-hydroxyapatite/chitosan scaffolds on rat calvarial defects for bone regeneration

BACKGROUND

This study aims at determining the biological effect of 75/25 w/w nano-hydroxyapatite/chitosan (nHAp/CS) scaffolds on bone regeneration, in terms of fraction of bone regeneration (FBR), total number of osteocytes (Ost), and osteocyte cell density (CD), as well as its biodegradability.

METHODS

Two critical-size defects (CSDs) were bilaterally trephined in the parietal bone of 36 adult Sprague-Dawley rats (18 males and 18 females); the left remained empty (group A), while the right CSD was filled with nHAp/CS scaffold (group B). Two female rats died postoperatively. Twelve, 11, and 11 rats were euthanized at 2, 4, and 8 weeks post-surgery, respectively. Subsequently, 34 specimens were resected containing both CSDs. Histological and histomorphometric analyses were performed to determine the FBR, calculated as [the sum of areas of newly formed bone in lateral and central regions of interest (ROIs)]/area of the original defect, as well as the Ost and the CD (Ost/mm2) in each ROI of both groups (A and B). Moreover, biodegradability of the nHAp/CS scaffolds was estimated via the surface area of the biomaterial (BmA) in the 2nd, 4th, and 8th week post-surgery.

RESULTS

The FBR of group B increased significantly from 2nd to 8th week compared to group A (P = 0.009). Both the mean CD and the mean Ost values of group B increased compared to group A (P = 0.004 and P < 0.05 respectively). Moreover, the mean value of BmA decreased from 2nd to 8th week (P = 0.001).

CONCLUSIONS

Based on histological and histomorphometric results, we support that 75/25 w/w nHAp/CS scaffolds provide an effective space for new bone formation.

A novel success scale for evaluating alveolar cleft repair using cone-beam computed tomography

PURPOSE

Radiographic scales, based on plain radiographs, for the evaluation of alveolar cleft repair, have certain weaknesses and are thought to overestimate to some degree the success of the surgical intervention. The aim of this study was the presentation of a novel success scale for evaluating alveolar cleft repair using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Patients treated with secondary osteoplasty for unilateral or bilateral alveolar cleft were evaluated using the Bergland and Enemark scales, as well as the novel success scale, which measures the bone height, the bone width and the level of the nasal floor.

RESULTS

A total of 44 patients with a total of 53 alveolar cleft sites were included. According to the new scale, 60% of the cases were defined as successful, with moderate (kappa = 0.511) or substantial (kappa = 0.718) agreement, between the new scale and the Bergland or Enemark scale, respectively. Statistically significant correlation was reported between the new success scale and the closure of space of the lateral incisor, the patient's age at surgery, the graft revision and the presence of residual fistula.

CONCLUSIONS

The novel success scale for evaluating alveolar cleft repair using CBCT takes into consideration all dimensions of the bony bridge. Future application is necessary for validation of its potential value.

Best clinical practice guidance for prescribing dental radiographs in children and adolescents: an EAPD policy document

BACKGROUND

The European Academy of Paediatric Dentistry (EAPD) proposes this best clinical practice guidance to help practitioners decide when and how to prescribe dental radiographs in children and adolescents.

METHODS

Four expert working groups conducted each a systematic review of the literature. The main subjects were radiation protection, intraoral dental radiography (bitewing and periapical radiographs), panoramic radiography (PR) and cone-beam computed tomography (CBCT). In addition, three workshops were held during the corresponding EAPD Interim Seminar in Chania (Crete, Greece) in 2019. On the basis of the identified evidence, all invited experts presented their findings and during the workshops aspects of clinical relevance were discussed.

RESULTS

Several clinical-based recommendations and statements were agreed upon.

CONCLUSION

There is no or low-grade evidence about the efficacy of dental radiographic examinations in young populations. The given recommendations and rationales should be understood as best clinical practice guidance. It is essential to respect the radiological principles of an individualized and patient-specific justification. When a dental radiograph is required, its application needs to be optimized, aiming at limiting the patient's exposure to ionising radiation according to the ALADAIP principle (As Low As Diagnostically Achievable being Indication-oriented and Patient-specific).

Application of nano-hydroxyapatite/chitosan scaffolds on rat calvarial critical-sized defects: A pilot study

BACKGROUND

The purpose of this pilot study was to evaluate for the first time the effect of 75/25 w/w nano-Hydroxyapatite/Chitosan (nHAp/CS) scaffolds on Guided Bone Regeneration (GBR) in rat calvarial critical-sized defects (CSDs).

MATERIAL AND METHODS

Six adult Sprague Dawley rats, 3 males and 3 females, were used. Two CSDs, full thickness and 5mm in diameter, were trephined in both sides of the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. The wound was sutured in layers. Rats were euthanized with diethyl ether inhalation at 2, 4 and 8 weeks after surgical procedure. Histological and histomorphometric analysis was performed within distinct regions of interest (ROI): the lateral area inward of the middle sagittal seam; the lateral area outward of the middle sagittal seam and the central area.

RESULTS

The mean surface of newly formed bone (in μm2) in the lateral area inward of the middle sagittal seam of all rats was significantly higher (P=0.039) in the experimental group (91733.00±38855.60) than the control group (46762.17±25507.97). The NOex-c, defined as total number of osteocytes (OST) in newly formed bone surface in experimental group [experimental OST] minus the total number of osteocytes in newly formed bone surface in control group [control OST], was significantly greater (P=0.029) at 4th week post-surgery. Within the experimental group, a statistically significant increase (P=0.042) in the surface of newly formed bone was noticed in rats euthanized in 4th week compared with rats euthanized in 2nd week after surgery in the lateral area inward of the middle sagittal seam.

CONCLUSIONS

The results of this study suggest that 75/25 w/w nHAp/CS scaffolds should be considered as a suitable biomaterial for GBR.

Recurrence in a patient with a 10-year history of sinonasal mucosal melanoma manifesting as facial swelling

Sinonasal mucosal melanoma is a rare tumor that develops slowly and may manifest with non specific signs and symptoms, causing significant delay in diagnosis. Local recurrence is common and usually occurs within the first two years after the initial treatment. Prognosis of recurrent lesions is poor and 5-year survival ranges between 10-47%. We report the clinical, radiographic, histopathological and immunohistochemical findings of a recurrent sinonasal mucosal melanoma which was diagnosed 10 years after the initial treatment, in a patient who presented with unilateral facial swelling and one-sided difficulty in breathing of two years duration. We discuss the causes of late diagnosis and review the negative predictive factors for recurrence and survival. As early diagnosis is of paramount importance for prognosis, we emphasize the signs and symptoms of patients with a history of sinonasal mucosal melanoma which should raise the suspicion for recurrence, in spite of a long time interval since diagnosis. Key words: Mucosal melanoma, nasal cavity, sinus, recurrence.

The frequency of non-syndromic distomolar teeth in a Greek population sample?

Background

To investigate the frequency of non-syndromic distomolars in a Greek population sample.

Material and Methods

The study population of this retrospective study consisted of 859 Orthopantomograms (OPGs) of 425 male and 434 female patients, attended the Department of Oral Diagnosis and Radiology, Dental School of Athens seeking for treatment. The OPGs were taken as a part of the patients treatment planning. Patients’ mean age was 33.57 years. Exclusion criteria from this study was cleft lip ± palate and diseases associated with systemic conditions and syndromes (such as cleidocranial dysplasia and Gardner syndrome). OPGs were only included in the study if at least one 3rd molar was present. The data collected were the number of 3rd molars, the number of distomolars, the age and the gender of each patient, information concerning previous extraction of 3rd molars. Statistical evaluation of the data included descriptive and bivariate analyses (Chi-square test and Spearman’s rho correlation coefficient). In an attempt to further estimate the correlation between the presence of upper and lower 3rd conditions we assumed that the absence of 3rd molars, the presence of 3rd molars, and the presence of distomolars was ordinal in nature and we calculated the Spearman Correlation Coefficient.

Results

The number of distomolars was greater in the maxilla than in the mandible. In the maxilla the distomolars were located almost equally in both left and right side. It was more possible lower left distomolars to be present in males than in females. Furthermore, males present higher prevalence of supernumerary teeth than females.

Conclusions

Early radiographic diagnosis of distomolars is fundamental so as to prevent complications such malocclusion, delayed eruption or displacement root or/ and resorption of adjacent teeth, pulp necrosis, follicular cyst, pain.

Key words:Non syndromic, distomolars, supernumerary molars, fourth molars.

Establishment of diagnostic reference levels for dental panoramic radiography in Greece

The purpose of the present study was to present the national diagnostic reference levels (DRL) established for panoramic dental examinations in Greece. The establishment of DRL, as a tool for the optimisation of radiological procedures, is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 90 panoramic systems have been used for the derivation of DRL values. DRL values have been proposed for exposure settings of different patient types (child, small adult and standard adult), both for film and digital imaging. The DRLs for different patient types are grouped in three categories: children, small adults (corresponding to female) and average adults (corresponding to male). Proposed DRLs for these groups are 2.2, 3.3 and 4.1 mGy, respectively. In order to investigate the correlation of DRLs with the available imaging modalities (CR, DR and film), this parameter was taken into account. DR imaging DRL is the lowest at 3.5 mGy, CR imaging the highest at 4.2 mGy and film imaging at 3.7 mGy. In order to facilitate comparison with other studies, kerma-width product values were calculated from Ki, air and field size.

Extra- and intra-cranial arterial calcifications in adults depicted as incidental findings on cone beam CT images

OBJECTIVE

The aim of this study was to evaluate, retrospectively, the gender- and age-related prevalence of incidentally found calcifications, depicted within the course of the extra- and intra-cranial portion of internal carotid artery (ICA), in cone beam computed tomography (CBCT) examinations in adults, and to assess their clinical significance.

MATERIALS AND METHODS

Out of a pull of 700 CBCT examinations a total of 484 CBCT scans of adult patients were finally selected according to a set of pre-defined criteria. These were evaluated for arterial calcifications presence within the ICAs course according to gender and age criteria.

RESULTS

In total, 492 calcifications were detected: 211 (42.88%) extra-cranial and 281 (57.11%) intra-cranial. Those were recorded in 150 scans (30.99%) and 161 scans (33.26%), respectively. Calcifications, with either extra- or intra-cranial allocation, were found more frequent in males than in females (all p-values < 0.05); also patients who presented with positive findings were older than those without findings (all p-values < 0.05). Furthermore, calcification presence with either extra- or intra-cranial allocation increases with age (all p-values < 0.05).

CONCLUSION

Significant calcification frequencies were found within the ICA's course, in CBCT scans. Moreover, an increased incidence of either extra- or intra-cranial presence of these depictions and its relation to age and gender was documented.

Association between extra- and intracranial calcifications of the internal carotid artery: a CBCT imaging study

OBJECTIVES

This study aimed to evaluate the association between the extracranial and intracranial calcification depiction of the internal carotid artery (ICA), incidentally found in CBCT examinations in adults, and to discuss the conspicuous clinical implications.

METHODS

Out of a series of 1085 CBCT examinations, 705 CBCT scans were selected according to pre-defined criteria. The extra- and intracranial calcifications depicted along the course of the ICA were documented according to a comprehensive set of descriptive criteria.

RESULTS

In total, 799 findings were detected, 60.1% (n = 480) were intracranially and 39.9% (n = 319) were extracranially allocated. The χ(2) test showed associations between all variables (p < 0.001). Also, most of the combinations of variables showed statistically significant results in the McNemar's test (p < 0.001).

CONCLUSIONS

We found that a significant correlation exists between extra- and intracranial calcifications of the ICA. It is clear that in cases of the presence of a calcification in the ICA extracranially, the artery's intracranial portion has an increased risk of showing the same findings. CBCT imaging is widely used as a diagnostic tool, thus, our results contribute to the identification of a subgroup of patients who should undergo further medical evaluation of the atherosclerosis of the ICAs.

Establishment of diagnostic reference levels for dental intraoral radiography

Diagnostic reference levels (DRLs) is a tool for the optimisation of radiological procedures. Establishment of a DRL is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 529 dental intraoral radiographic facilities have been used in order to define DRLs for digital and film imaging modalities, taking into account the region of the mouth to be imaged. Thus, different DRL values have been proposed for minimum (usually incisors), maximum (usually maxillary molars) and average exposure settings, both for film and digital imaging. The results have been compared with similar studies performed in Europe and the USA and are in line with the most recent ones.

Recommendations for the development of e-modules for the continuing professional development of European dentists

AIMS

To provide evidence-based and peer-reviewed recommendations for the development of dental continuing professional development (CPD) learning e-modules.

METHODS

The present recommendations are consensus recommendations of the DentCPD project team and were informed by a literature research, consultations from e-learning and IT expert, discussions amongst the participants attending a special interest group during the 2012 ADEE meeting, and feedback from the evaluation procedures of the exemplar e-module (as described in a companion paper within this Supplement). The main focus of these recommendations is on the courses and modules organised and offered by dental schools.

RESULTS AND DISCUSSION

E-modules for dental CPD, as well as for other health professionals' continuing education, have been implemented and evaluated for a number of years. Research shows that the development of e-modules is a team process, undertaken by academics, subject experts, pedagogists, IT and web designers, learning technologists and librarians. The e-module must have clear learning objectives (outcomes), addressing the learners' individual needs, and must be visually attractive, relevant, interactive, promoting critical thinking and providing feedback. The text, graphics and animations must support the objectives and enable the learning process by creating an attractive, easy to navigate and interactive electronic environment. Technology is usually a concern for learners and tutors; therefore, it must be kept simple and interoperable within different systems and software. The pedagogical and technological proficiency of educators is of paramount importance, yet remains a challenge in many instances.

CONCLUSIONS

The development of e-courses and modules for dental CPD is an endeavour undertaken by a group of professionals. It must be underpinned by sound pedagogical and e-learning principles and must incorporate elements for effective visual learning and visual design and a simple, consistent technology.

The development of an exemplar e-module for the continuing professional development of European dentists

AIM

To present the development of an exemplar e-module for dental continuing professional development (CPD) provided by dental schools and other dental educational providers.

MATERIALS AND METHODS

The exemplar e-module covered the topic of 'Sterilisation and cross-infection control in the dental practice' as this is one of the most recommended topics for dental CPD in Europe. It was developed by a group of topic experts, adult learning and distance learning experts and a technical developer. Major concerns were pedagogy, interoperability, usability and cost reduction. Open-source material was used to reduce the cost of development.

RESULTS

The e-module was pre-piloted in dental practitioners for usability and then evaluated by experts in the field and dental academics through an electronic questionnaire and an online presentation and discussion at the ADEE 2012 Special Interest Group on DentCPD-Lifelong learning. This facilitated refinement before final production. A Creative Commons License was implemented to ensure the developers' rights and facilitate wider distribution and access to CPD providers.

DISCUSSION AND CONCLUSIONS

The e-module was developed according to well-defined pedagogical and technical guidelines for developing e-learning material for adult learners. It was structured to promote self-study by directing learners through their study, promoting interaction with the material, offering explanation and providing feedback. Content validity was ensured by extensive review by experts. The next step would be to expand the evaluation to practising dentists in various countries after relevant translations, and adaptations to local policies have been made.

Continuing professional development systems and requirements for graduate dentists in the EU: survey results from the DentCPD project

INTRODUCTION

By maintaining skills and keeping dentists up-to-date, continuing professional development (CPD) supports safe clinical practice. However, CPD for dentists across Europe is not harmonised.

AIM

One aim of the 'DentCPD' project (www.dentcpd.org) was to identify and agree essential CPD requirements for EU dentists. As part of the process, data were collected on existing approaches to CPD for EU dentists. This paper reports those findings.

METHODS

Informed by a review of the literature and internet search, the CPD for Graduate Dentists questionnaire gathered data from dental educators on CPD systems, requirements, provision and accreditation in Europe. It sought opinion on mandatory CPD and e-learning.

RESULTS

Responses were received from 143 individuals from 30 EU countries. About half the countries had a compulsory CPD system which typically included mandatory core topics. Elsewhere CPD was optional or based on recommended hours. University dental schools and professional dental associations were the most common CPD providers. National regulatory bodies were the most common accrediting body. Only 41% of respondents thought they knew the criteria for successful accreditation of CPD. Eighty-one percent agreed that 'CPD should be obligatory for all dentists'.

CONCLUSION

These results present an overview of the status of CPD for EU dentists. Despite a notable trend towards regulated CPD systems, current requirements for dentists to engage in CPD show variation. The harmonisation of requirements would enhance both dentist mobility and safe clinical practice.

Variability of dental cone beam CT grey values for density estimations

OBJECTIVE

The aim of this study was to investigate the use of dental cone beam CT (CBCT) grey values for density estimations by calculating the correlation with multislice CT (MSCT) values and the grey value error after recalibration.

METHODS

A polymethyl methacrylate (PMMA) phantom was developed containing inserts of different density: air, PMMA, hydroxyapatite (HA) 50 mg cm(-3), HA 100, HA 200 and aluminium. The phantom was scanned on 13 CBCT devices and 1 MSCT device. Correlation between CBCT grey values and CT numbers was calculated, and the average error of the CBCT values was estimated in the medium-density range after recalibration.

RESULTS

Pearson correlation coefficients ranged between 0.7014 and 0.9996 in the full-density range and between 0.5620 and 0.9991 in the medium-density range. The average error of CBCT voxel values in the medium-density range was between 35 and 1562.

CONCLUSION

Even though most CBCT devices showed a good overall correlation with CT numbers, large errors can be seen when using the grey values in a quantitative way. Although it could be possible to obtain pseudo-Hounsfield units from certain CBCTs, alternative methods of assessing bone tissue should be further investigated.

ADVANCES IN KNOWLEDGE

The suitability of dental CBCT for density estimations was assessed, involving a large number of devices and protocols. The possibility for grey value calibration was thoroughly investigated.

Continuing professional development systems and requirements for graduate dentists in the EU: survey results from the DentCPD project

INTRODUCTION

By maintaining skills and keeping dentists up-to-date, continuing professional development (CPD) supports safe clinical practice. However, CPD for dentists across Europe is not harmonised.

AIM

One aim of the 'DentCPD' project (www.dentcpd.org) was to identify and agree essential CPD requirements for EU dentists. As part of the process, data were collected on existing approaches to CPD for EU dentists. This paper reports those findings.

METHODS

Informed by a review of the literature and internet search, the CPD for Graduate Dentists questionnaire gathered data from dental educators on CPD systems, requirements, provision and accreditation in Europe. It sought opinion on mandatory CPD and e-learning.

RESULTS

Responses were received from 143 individuals from 30 EU countries. About half the countries had a compulsory CPD system which typically included mandatory core topics. Elsewhere CPD was optional or based on recommended hours. University dental schools and professional dental associations were the most common CPD providers. National regulatory bodies were the most common accrediting body. Only 41% of respondents thought they knew the criteria for successful accreditation of CPD. Eighty-one percent agreed that 'CPD should be obligatory for all dentists'.

CONCLUSION

These results present an overview of the status of CPD for EU dentists. Despite a notable trend towards regulated CPD systems, current requirements for dentists to engage in CPD show variation. The harmonisation of requirements would enhance both dentist mobility and safe clinical practice.

Evaluation of a blended learning course for teaching oral radiology to undergraduate dental students

AIMS

The purpose of this study was to develop and implement a blended course (a combined face-to-face and online instruction) on undergraduate oral radiology and evaluate it by comparing its educational effectiveness (derived from students' performance and answers to questionnaires) to a conventional course's. Students' attitudes concerning the blended methodology were also registered.

METHODOLOGY

An original course was developed and implemented, and its electronic version was uploaded to an e-learning educational platform. The course was attended by two groups of final-year students, who were taught by either the conventional face-to-face methodology or the blended learning methodology. Students answered a series of questionnaires, before and after following the course, regarding their perceptions, attitudes and evaluation of the course. Additionally, they completed knowledge assessment tests and their grades (before and after the course) were compared. Educational effectiveness of the course was determined by analysing the results of the questionnaires and the tests.

RESULTS

Students in the blended group performed significantly better than their colleagues of the conventional group in the post-course knowledge test, and female students of the blended group performed better than male students. Students evaluated high the course content, organisation, educational material, and the blended group students additionally appreciated the course design and clarity of instructions. Students' attitudes towards elements of blended learning (effectiveness, motivation and active engagement) were very positive. Most of the blended group students, who attended the face-to-face meeting (approx. 91%), evaluated it as helpful for summarising the subject and clarifying difficult issues.

CONCLUSIONS

Blended learning is effective and well evaluated by dental students and can be implemented in undergraduate curriculum for teaching oral radiology.

Quantification of metal artifacts on cone beam computed tomography images

OBJECTIVES

To quantify metal artifacts obtained from a wide range of cone beam computed tomography (CBCT) devices and exposure protocols, to compare their tolerance to metals of different densities, and to provide insights regarding the possible implementation of metal artifact analysis into a QC protocol for CBCT.

MATERIALS AND METHODS

A customized polymethyl methacrylate (PMMA) phantom, containing titanium and lead rods, was fabricated. It was scanned on 13 CBCT devices and one multi-slice computed tomography (MSCT) device, including high-dose and low-dose exposure protocols. Artifacts from the rods were assessed by two observers by measuring the standard deviation of voxel values in the vicinity of the rods, and normalizing this value to the percentage of the theoretical maximum standard deviation.

RESULTS

For CBCT datasets, artifact values ranged between 6.1% and 27.4% for titanium, and between 10.% and 43.7% for lead. Most CBCT devices performed worse than MSCT for titanium artifacts, but all of them performed better for lead artifacts. In general, no clear improvement of metal artifacts was seen for high-dose protocols, although certain devices showed some artifact reduction for large FOV or high exposure protocols.

CONCLUSIONS

Regions in the vicinity of the metal rods were moderately or gravely affected, particularly in the area between the rods. In practice, the CBCT user has very limited possibilities to reduce artifacts. Researchers and manufacturers need to combine their efforts in optimizing exposure factors and implementing metal artifact reduction algorithms.

Development and applicability of a quality control phantom for dental cone-beam CT

Cone‐beam CT (CBCT) has shown to be a useful imaging modality for various dentomaxillofacial applications. However, optimization and quality control of dental CBCT devices is hampered due to the lack of an appropriate tool for image quality assessment. To investigate the application of different image quality parameters for CBCT, a prototype polymethyl methacrylate (PMMA) cylindrical phantom with inserts for image quality analysis was developed. Applicability and reproducibility of the phantom were assessed using seven CBCT devices with different scanning protocols. Image quality parameters evaluated were: CT number correlation, contrast resolution, image homogeneity and uniformity, point spread function, and metal artifacts. Deviations of repeated measurements were between 0.0% and 3.3%. Correlation coefficients of CBCT voxel values with CT numbers ranged between 0.68 and 1.00. Contrast‐to‐noise ratio (CNR) values were much lower for hydroxyapatite (0<CNR<7.7) than for air and aluminum (5.0<CNR<32.8). Noise values ranged between 35 and 419. The uniformity index was between 3.3% and 11.9%. Full width at half maximum (FWHM) measurements varied between 0.43 mm and 1.07 mm. The increase of mean voxel values surrounding metal objects ranged between 6.7% and 43.0%. Results from preliminary analyses of the prototype quality control phantom showed its potential for routine quality assurance on CBCT. Large differences in image quality performance were seen between CBCT devices. Based on the initial evaluations, the phantom can be optimized and validated.

PACS numbers: 87.57.C‐, 87.57.N‐, 87.57.Q‐

Treatment of periodontal endosseous defects with platelet-rich plasma alone or in combination with demineralized freeze-dried bone allograft: a comparative clinical trial

BACKGROUND

Platelet-rich plasma (PRP) alone or combined with other regenerative materials was previously studied in human periodontal endosseous defects. There are no sufficient data evaluating to what extent the addition of demineralized freeze-dried bone allograft (DFDBA) to PRP may enhance the effectiveness of PRP. The aim of this randomized, double-masked, controlled clinical trial was to compare the effectiveness of autologous PRP alone to PRP + DFDBA in periodontal endosseous defects.

METHODS

Twenty-four proximal endosseous defects in 24 patients with severe chronic periodontitis were randomly treated with PRP alone or in combination with DFDBA. The final evaluation at 6 months was based on clinical and radiographic parameters. Subtraction radiography was used. The primary outcome variable was clinical attachment level (CAL).

RESULTS

The two treatment groups were initially comparable (mean CAL: 8.67 +/- 2.19 mm for PRP + DFDBA and 8.25 +/- 1.96 mm for PRP). Both treatments achieved statistically significant and similar CAL gain (3.08 +/- 1.17 mm for PRP + DFDBA and 3.08 +/- 0.95 mm for PRP), probing depth, defect depth, and area surface reduction. The percentage of defect fill did not significantly differ between the two treatments. There was a non-significant trend to greater defect fill (45.42% versus 41.29%), defect depth (54.05% versus 49.52%), and area surface (58.43% versus 52.16%) reduction with the graft. In both groups, 66.66% of the defects gained > or =3 mm of CAL.

CONCLUSION

Within its limits, this study demonstrates that both PRP and PRP combined with DFDBA resulted in significant clinical and radiographic improvement in human periodontal endosseous defects at 6 months, and the addition of DFDBA to PRP did not significantly enhance the treatment outcome.

Evaluation of the severity of temporomandibular joint osteoarthritic changes related to age using cone beam computed tomography

OBJECTIVES

The aim of this study is to evaluate and correlate with age the severity of temporomandibular joint (TMJ) osteoarthritic changes using cone beam CT (CBCT).

METHODS

The images of 71 patients with findings of degenerative arthritis were retrieved from the computer data base. All patients had been examined with CBCT (NewTom 9000 QR-DVT). Left and right TMJs were evaluated independently for each patient. TMJ evaluation included: (a) bony changes of the condyle (flattening, erosion, sclerosis, osteophytes, resorption); (b) joint space (normal, increased, reduced, bony contact between the condyle and the mandibular fossa); and (c) bony changes of mandibular fossa (normal, sclerosis, erosion, resorption). The radiographic findings were statistically analysed.

RESULTS

Significant differences in the mean age were found: (a) between absent and moderate erosion (P = 0.019), as well as between absent and extensive erosion (P = 0.048); (b) between absent and extensive formation of osteophyte (P = 0.003), as well as between slight and extensive formation of osteophyte (P = 0.025); (c) between normal joint space and bony contact (P = 0.0002), as well as between reduced joint space and bony contact (P = 0.001).

CONCLUSIONS

Degenerative arthritis is an age-related disease. The progression and severity of osseous changes in the condylar head and mandibular fossa are increased with age. In older age groups, patients are expected to have more frequent and severe progressive degenerative bony changes due to the development of TMJ osteoarthritis than patients in younger age groups.

Reliability of panoramic radiograph for carotid atheroma detection: a study in patients who fulfill the criteria for carotid endarterectomy

OBJECTIVES

To evaluate the reliability of panoramic radiograph (PR) for carotid artery atheroma detection, by comparing its results with the carotid-vertebral digital subtraction angiography (DSA) findings, as well as with the detected calcium deposition in the carotid plaques, which were surgically resected, using direct radiographs.

STUDY DESIGN

Forty consecutive patients suffering from carotid artery atherosclerotic occlusive disease confirmed by preoperative DSA, fulfilling the criteria for carotid endarterectomy, were operated on. Preoperatively, all of the patients had undergone PR, while postoperatively all of the surgically resected carotid plaques were radiographed using radiographic films and submitted to histologic examination. Compared with the DSA and the radiographic film findings, the PR results were classified as: 1) true-positive; 2) true-negative; 3) false-positive; or 4) false-negative.

RESULTS

Panoramic radiograph has low sensitivity and specificity compared with the DSA findings and the direct radiographs results. However, a positive predictive value (PPV) of 100% per patient as well as for luminal stenosis >80% was documented.

CONCLUSION

Even in the subgroup of patients who fulfill the criteria for carotid endarterectomy, PR has a low sensitivity and specificity; therefore, it cannot be considered to be a useful screening tool for atheroma detection in the general dental population. However, the 100% PPV per patient and for luminal stenosis >80%, indicates that positive calcification PR findings at the C(3)-C(4) region are highly suggestive for carotid artery atherosclerotic occlusive disease. Therefore, especially asymptomatic patients should be referred for further examination.

The subjective image quality of conventional and digital panoramic radiography among 6 to 10 year old children

OBJECTIVES

To compare the diagnostic quality of orthopantomographs made with the conventional unit Orthophos Siemens and the direct digital unit Planmeca 2000 cc Proline among children 6-10 years old and to investigate possible diferences on image interpretation between oral radiologists and pediatric dentists.

METHODS

Study material included two independent groups of panoramic images (50 in each group) made with different panoramic modalities (digital conventional). Eight observers (four pediatric dentists and four oral radiologists) evaluated all images for diagnostic quality in 12 pre-determined areas using a 4-point rating scale.

RESULTS

Digital and conventional panoramic radiography performed almost similarly as far as it concerns the specific diagnostic tasks rated with the exception of the interproximal contacts of mandibular molars where digital panoramic radiography was scored significantly higher and the periapical region of anterior mandible and anterior mandibular tooth germs where conventional panoramic radiography was found to be significantly better. Both oral radiologists and pediatric dentists graded similarly digital and conventional radiographs for a variety of diagnostic tasks.

CONCLUSIONS

It can be concluded that diagnostic image quality obtained with the digital orthopantomograph unit Planmeca 2000 cc Proline was generally equal to image quality obtained with the conventional orthopantomograph unit Orthophos Plus CD. Image interpretation between oral radiologists and pediatric dentists was not substantially different

Dose reduction in maxillofacial imaging using low dose Cone Beam CT

OBJECTIVES

(a) To measure the absorbed dose at certain anatomical sites of a RANDO phantom and to estimate the effective dose in radiographic imaging of the jaws using low dose Cone Beam computed tomography (CBCT) and (b) to compare the absorbed and the effective doses between thyroid and cervical spine shielding and non-shielding techniques.

STUDY DESIGN

Thermoluminescent dosimeters (TLD-100) were placed at 14 sites in a RANDO phantom, using a Cone Beam CT device (Newtom, Model QR-DVT 9000, Verona, Italy). Dosimetry was carried out applying two techniques: in the first, there was no shielding device used while in the second one, a shielding device (EUREKA!, TRIX) was applied for protection of the thyroid gland and the cervical spine. Effective dose was estimated according to ICRP(60) report (E(ICRP)). An additional estimation of the effective dose was accomplished including the doses of the salivary glands (E(SAL)). A Wilcoxon Signed Ranks Test was used for statistical analysis.

RESULTS

In the non-shielding technique the absorbed doses ranged from 0.16 to 1.67 mGy, while 0.32 and 1.28 mGy were the doses to the thyroid and the cervical spine, respectively. The effective dose, E(ICRP), was 0.035 mSv and the E(SAL) was 0.064 mSv. In the shielding technique, the absorbed doses ranged from 0.09 to 1.64 mGy, while 0.18 and 0.95 mGy were the respective values for the thyroid and the cervical spine. The effective dose, E(ICRP), was 0.023 mSv and E(SAL) was 0.052 mSv.

CONCLUSIONS

The use of CBCT for maxillofacial imaging results in a reduced absorbed and effective dose. The use of lead shielding leads to a further reduction of the absorbed doses of thyroid and cervical spine, as well as the effective dose.

Radiographic examination of the temporomandibular joint using cone beam computed tomography

Cone beam CT (CBCT) is a new technique for maxillofacial imaging. We describe a reconstruction technique for radiographic examination of the temporomandibular joint (TMJ) using CBCT, and we further present four cases where the technique was employed. The technique provides a complete radiographic investigation of the bony components of the TMJ. The reconstructed images are of high diagnostic quality. The examination time is shorter and the patient dose is lower than that with conventional CT. It may therefore be considered as the imaging technique of choice when investigation of bony changes of the TMJ is the task at hand.

Psychophysical properties of a new F-speed intraoral film

OBJECTIVES

To compare the psychophysical properties of the new Kodak InSight F-speed intraoral dental film with those for the E-speed Ektaspeed Plus film by means of the perceptibility curve (PC) test.

METHODS

A specially designed test object was used. The test object was made of aluminium and was 10 mm thick. It contained ten holes, contrast details, with the same diameter of 1.5 mm but with different depths. The depths ranged from 0.03 mm to 0.30 mm in steps of 0.03 mm. The holes were placed randomly within a square area with a total of 16 possible positions. Radiographs of the test object were obtained over the full exposure ranges of the two films. A Combex DX-907 dental X-ray unit was used operating at 10 mA and two tube potentials, 70 kVp and 90 kVp. The focus-to-object distance was 50 cm. Ten observers evaluated the radiographs under uniform artificial lighting using a view box and stated the number of perceptible representations of contrast details. In order to construct perceptibility curves, absolute values of the reciprocal of the minimum perceptible logarithmic exposure differences, 1/(DeltalogE)min, were plotted as functions of the logarithm of exposures, logE, registered by the tested films. Comparisons between the two films were made separately for the two tube potentials, 70 kVp and 90 kVp.

RESULTS

The results are presented graphically. PCs for the InSight film had higher peaks than those for the Ektaspeed Plus film. This indicates that the viewers were able to perceive smaller exposure differences in the former compared with the latter. PCs for the InSight film were shifted towards the left along the exposure axis relative to the PCs for the Ektaspeed Plus film indicating that the former film is more sensitive than the latter. The integrals of the PCs for InSight film were larger than those for Ektaspeed film indicating superior psychophysical properties of the InSight film.

CONCLUSIONS

From the point of view of perception, the new InSight film has such psychophysical properties in comparison with Ektaspeed Plus film that it will be the more favourable of the two in clinical radiographic practice.

Clinical and radiographic comparison of three regenerative procedures in the treatment of intrabony defects

The purpose of this study was to compare clinically and radiographically the results obtained following application of (1) commercially available demineralized freeze-dried bone allograft (DFDBA), (2) guided tissue regeneration (GTR) using a bioabsorbable polylactic acid softened with citric acid ester barrier, and (3) enamel matrix derivative gel (EMD), in the treatment of two- and three-walled intrabony defects. The study included 39 patients--12 in the DFDBA group, 12 in the GTR group, and 15 in the EMD group--each with one treated defect. Clinical measurements, Plaque Index, Gingival Index, probing depths, clinical attachment levels, and recession were comparable in the three groups at baseline. Measurements were repeated 12 months postoperative. Surgical measurements were also comparable at baseline among the groups. Radiographs were taken at baseline and 12 months later, and they were compared after reconstruction of the postoperative radiograph by a software program that produces geometric standardization. No significant differences in clinical results among the three groups were found. Radiographic assessment indicated a slight, nonsignificant difference in mean crestal bone resorption and defect fill between the groups. However, the mean improvement in intrabony depth was greater in the GTR and EMD groups than in the DFDBA group. The three regenerative procedures appeared to be equally effective in treating intrabony defects, with the exception of radiographic defect resolution, which was significantly greater in the GTR and EMD groups than in the DFDBA group.

Localized jaw enlargement in renal osteodystrophy: report of a case and review of the literature

Renal osteodystrophy is a common long-term complication of end-stage renal disease. Involvement of the jaws is common and radiographic alterations are often one of the earliest signs of chronic renal disease. However, marked enlargement of the jaws is a rare complication of renal osteodystrophy. A case of localized asymptomatic enlargement of the mandible in a 38-year-old woman with chronic renal failure is presented. The clinical, radiographic, and histological findings were consistent with renal osteodystrophy. To our knowledge, this is the third case of localized mandibular enlargement of renal osteodystrophy reported in the English-language literature.

Absorbed radiation dose during lateral cephalometric radiography: comparison of screen-film systems and field-size combinations

Various methods have been proposed and investigated in order to reduce radiation exposure in cephalometric radiography. The aim of this study was to determine the radiation dose absorbed by nine specific superficial anatomical regions of the head and neck, in children aged 9 to 17 years, by the use of three combinations of intensifying screens and films and different field sizes. A dental X-ray unit (Ortho Phos, Siemens) was used for the radiographic exposures and the absorbed doses were measured via thermoluminescence dosemeters. The mean doses corresponding to the anatomical regions in question were higher with the first than with the other two techniques (p < 0.05) without the thyroid gland (p > 0.05) and in the third technique were lower than the doses of the other two techniques (p < 0.05) without the thyroid gland and the tip of the nose (p > 0.05).

Clinical and radiographic findings following application of enamel matrix derivative in the treatment of intrabony defects. A series of case reports

AIM

The purpose of this case report study was to evaluate the clinical and radiographic findings following application of enamel matrix derivative (EMD) in the treatment of 2- or 3-wall intrabony defects in a private periodontal practice one year after surgery.

METHOD

15 consecutive patients (age range 38 67 years, 9 females, 6 males, 3 smokers) with 25 intrabony defects were included in the study. The decision to use reconstructive surgery was taken at least 3 months after termination of the presurgical treatment phase. Inclusion criteria were: presence of an interproximal area with residual probing depth (PD) > or =6 mm, probing attachment level (PAL) > or =6 mm and an associated intrabony defect > or =4 mm deep and > or =2 mm wide as measured during surgery (defects were not associated with adjacent furcation lesions). Open-flap surgery was performed to expose the defects and the EMD gel was applied after proper debridement. The patients were instructed to rinse 2x daily for 6 weeks with a 0.12% solution of chlorhexidine.

RESULTS

At 12 months, mean PD decreased from 8.4 mm to 4.0 mm and PAL from 10.2 mm to 6.6 mm, while recession increased from 1.8 mm to 2.6 mm. Residual PD greater than 4 mm was observed only in 7 sites. 14 sites demonstrated a PAL gain of 2-3 mm, 9 sites a gain of 4-5 mm and 2 sites a gain of 6 mm. Radiographic assessment indicated a mean crestal bone resorption of 20.7% and a mean improvement in the distance between the CEJ and the base of the defect of 22.9%. The combination of defect fill from the bottom of the defect and crestal resorption resulted in a mean defect resolution of 61%.

CONCLUSION

Within the limits of this study, the application of EMD gel in 2- or 3-wall intrabony defects resulted in clinically significant gain of PAL and radiographic bone. Further controlled clinical studies are required to confirm the effectiveness of the EMD gel in the treatment of various osseous defects.

Radiographic detection and assessment of the periodontal endosseous defects

AIMS

The aim of the present study was to investigate the potential of conventional radiography in detecting and accurately imaging periodontal endosseous (or osseous) defects when compared to surgical measurements. A further objective of the study was the selection of the most successful radiographic method for the assessment of endosseous defects.

METHOD

Surgical measurements, during periodontal flap surgery, and radiographic measurements, from periapical and panoramic radiographs, were obtained from 5,072 proximal surfaces of 100 patients presenting with periodontitis.

RESULTS

Statistical evaluation of the surgical and radiographic measurements revealed the following. (1) The ability of the radiographs to detect periodontal osseous defects was relatively low. (2) For periapical radiography, it depended, in descending order, on the depth and buccolingual width of the defect, the number of osseous walls and the jaw location. For panoramic radiography, it depended only on buccolingual width. (3) Osseous defects of small depth and/or small buccolingual width were the most difficult to detect radiographically. (4) Periapical radiography was more successful than panoramic in detecting osseous defects, and more accurate in assessing the defect dimensions (depth, mesiodistal width). (5) The difference in the defect detection ability between the 2 radiographic methods, the accuracy of the radiographic defect dimensions assessment as well as the degree of agreement between periapical and panoramic assessment depended on defect location and dimensions.

CONCLUSIONS

Periapical radiography is superior to panoramic in detecting and accurately imaging periodontal osseous destruction.

Mail survey of dental radiographic techniques and radiation doses in Greece

OBJECTIVES

To measure the entrance dose from periapical radiography in Greece and to determine the relative influence of factors affecting it.

METHODS

Special packs, containing a questionnaire, a film (X-Omat MA 18 x 22.4 cm, Ready Pack, Kodak-Pathe, Paris, France) with an attached aluminium stepwedge and a pre-exposed Ektaspeed Plus (Kodak) film, were mailed to 550 randomly selected dental practitioners. The results were tested statistically using an Analysis of Variance (level P < 0.05).

RESULTS

Three hundred and sixty-four packs were returned: 311 were complete but in 53 the pre-exposed film had not been developed. The average HVL was 1.4 mm Al 51% of the units had pointed cones and 34% a beam diameter larger than 6 cm. 54% of the dentists used E-speed films. Eighty per cent of the films were inadequately processed. For the total group the average entrance dose was 6.9 mGy (range 0.6-36 mGy), and 6.3 mGy (range 0.6-35 mGy) for the completed packs (n = 311). The radiation dose for the completed packs was significantly influenced by HVL, film speed, length of cone and standard of processing.

CONCLUSIONS

HVL, film speed, length of cone and standards of processing influence the entrance dose. Not all of the available measures for reducing radiation dose are commonly practised in Greece. Continuing education programs can help to improve radiation safety for dental patients.

Clinical application of a new bioresorbable guided tissue regeneration device: case reports

Bioresorbable barriers have been recently introduced in clinical practice for guided tissue regeneration therapy. One of these is the Guidor matrix barrier which is made of amorphous polylactic acid softened with a citric acid ester to increase malleability and facilitate clinical handling. The advantages of the bioresorbable barrier include: the elimination of second surgery; better handling and adaptation around the tooth and over the bone; and integration of the connective tissue of the flap with the barrier preventing epithelial migration, gingival recession, and pocket formation. In the case of matrix exposure the material disappears within 6 to 8 weeks. The purpose of this report is to present the clinical application of the Guidor matrix barrier in the treatment of two- or three-wall intrabony defects that were followed up for more than 1 year. The evaluation included soft tissue changes using clinical parameters and hard tissue changes using nonstandardized digital subtraction radiography. In the authors' opinion, the incorporation of a bioresorbable barrier in guided tissue regeneration therapy represents a significant improvement in the treatment of intrabony defects.

Comparison of 2 regenerative procedures--guided tissue regeneration and demineralized freeze-dried bone allograft--in the treatment of intrabony defects: a clinical and radiographic study

The purpose of this study was to compare clinically and radiographically the effectiveness of guided tissue regeneration (GTR), using a bioabsorbable polylactic acid softened with citric acid ester barrier and commercially available demineralized freeze-dried bone allograft (DFDBA) in the treatment of 2- and 3-wall intrabony defects. Twelve patients each with one treated defect comprised each group. Conservative treatment was completed 2 to 4 months prior to surgery. Clinical measurements, plaque index, gingival index, probing depths (PD), clinical attachment levels (CAL) and recession (REC), were comparable in both groups at baseline. They were repeated at 12 months. Surgical measurements were also comparable at baseline in both groups. In the GTR group, at baseline the mean distance between the cemento-enamel junction (CEJ) and base of the defect was 12.3 +/- 2.9 mm and in the DFDBA group 11.3 +/- 1.8 mm. The defect depth was 6.3 +/- 2.0 mm and 5.4 +/- 1.3 mm, respectively. Radiographs were taken at baseline and 12 months later and compared using non-standardized digital subtraction radiography. In the GTR group, mean PD decreased from 7.9 +/- 2.5 mm to 3.5 +/- 1.4 mm and mean CAL from 10.8 +/- 2.8 mm to 7.0 +/- 1.6 mm, the differences being statistically significant (P = 0.002), while REC increased from 2.9 +/- 1.2 mm to 3.5 +/- 1.1 mm. In the DFDBA group, mean PD decreased from 7.1 +/- 1.1 mm to 3.5 +/- 1.1 mm and mean CAL from 9.8 +/- 1.5 mm to 6.6 +/- 1.7 mm (P = 0.002), while REC increased from 2.8 +/- 1.0 mm to 3.1 +/- 1.2 mm. No significant differences were found when the clinical results of the 2 groups were compared. Radiographic differences between the baseline and reconstructed images 12 months later were observed in both groups. Mean crestal bone resorption was 15.3 +/- 22.5% in the GTR group and 10.4 +/- 31.8% in the DFDBA group, and mean improvement in the distance between the CEJ and the base of the defect was 22.8 +/- 18.1% in the GTR group and 15.3 +/- 13.6% in the DFDBA group. However, the mean improvement in the intrabony depth was larger in the GTR group (71.9 +/- 29.1%) than in the DFDBA group (35.4 +/- 21.6%) (P = 0.007). In conclusion, within the limits of this study, both regenerative procedures were beneficial in treating intrabony defects. No statistical significant differences were observed between the 2 groups, with the exception of radiographic defect resolution which was significantly greater in the GTR group.