Justification and optimization of dental panoramic tomography and lateral cephalometric radiography among Finnish children

Orthodontic treatment is common especially among children and adolescents. A dental panoramic tomograph (DPT) and a lateral cephalometric radiograph (LCR) are the main radiographic tools for orthodontic treatment planning. Children own higher radiosensitivity than adults, because of their developmental and physiological status. Therefore, during dental extra-oral radiography of children, implementation of the two first principles of radiation protection, the principles of justification and optimization, should be highlighted. Notably, however, qualitative assessments of orthodontic radiography had not been published before the present study. The study subjects were a random sample of 7- to 12-year-olds of whom a DPT and/or an LCR had been taken in the Oral Healthcare Department of the City of Helsinki in 2010. For DPTs, the sampling was repeated in 2013-2014 after an intervention. Retrospective analysis of the sample from 2010 revealed that 1) the vast majority of DPTs and all LCRs were ordered for orthodontic diagnostics, 2) the referrals were inadequate for nearly one-third of the images, 3) an adult program was used for taking most of the DPTs, 4) segmented DPT was never used, 5) most of the DPTs and LCRs displayed too extended field-size, 6) the number of repeated radiographs was almost at the permitted level, 7) almost one-third of the images lacked radiographic interpretation and cephalometric analysis, and 8) general and developmental pathologic findings were observed in the area of the dentition only. These results gave reason for an educational intervention program that particularly aimed at more appropriate DPT program selection in children. Its power was analysed by prospective evaluation of DPTs in 2013-2014, and a notable increase became evident in application of both segmented and child panoramic programs. This work disclosed deficiencies throughout the process of dental extra-oral radiography of children. It emerged that further need for continuing education in radiation protection exists for the whole dental team, especially the orthodontists and practitioners involved in orthodontics. Education was proven to positively affect the optimization process. In addition, the results endorse development of DPT- and LCR-device towards enhanced field limitation options for patients of different age and size and indications for dental extra-oral radiography.Lapset ovat herkempiä ionisoivalle säteilylle kuin aikuiset. Heidän säteilyriskinsä on kaksin - kolminkertainen aikuisten säteilyriskiin verrattuna. Siksi Suomen lainsäädännössä olevien säteilysuojelun oikeutus- ja optimointiperiaatteiden soveltamisella on suuri merkitys lasten röntgentutki¬muksissa. Säteilyturvakeskuksen mukaan hampaiston panoraamatomografia- eli PTG-kuvaus on yleisin röntgentutkimus ja kallolateraali- eli LCR-kuvaus toiseksi yleisin ekstraoraalinen röntgentutkimus 7-12-vuotiailla. Nämä tutkimukset ovat oleellinen osa oikomishoidon diagnostiikkaa. Tässä työssä tutkittiin PTG- ja LCR-kuvien oikeus- ja optimointiperiaatteiden toteutumista tarkoituksena löytää keinoja parantaa edelleen lasten säteilyturvallisuutta ja kuvaustoiminnan laatua. Tutkimuspopulaation muodostivat satunnaisesti valitut 7-12-vuotiaat helsinkiläislapset. Retrospektiivisissä tutkimuksissa selvisi, että suurin osa PTG-tutkimuksista ja kaikki LCR-tutkimukset oli tehty oikomishoidollisista syistä, lähetteiden laadussa ja lausunnoissa oli puutteita, valtaosa lasten PTG-kuvista oli otettu aikuisten ohjelmalla, osa-PTG-kuvia ei ollut otettu lainkaan, kuva-ala oli lähes poikkeuksetta liian iso, hukkakuvien määrä oli melkein hyväksyttävällä tasolla ja tutkituissa PTG-kuvissa kaikki merkitykselliset löydökset sijaitsivat hampaiston alueella eli kondyyleissä ja luustruktuurissa ei havaittu patologisia muutoksia. Havaintojen pohjalta toteutettiin prospektiivisesti Helsingin terveyskeskuksessa koko suun terveydenhuollon hoitotiimille suunnattu interventio, joka sisälsi luentoja lasten säteilysuojelusta. Intervention vaikutusta analysoitiin seuraamalla interventiota seuraavan vuoden ajan kuvausohjelmien valintaa 7-12-vuotiailla helsinkiläislapsilla, ja todettiin PTG-lapsiohjelman ja osa-PTG-ohjelmien käytön lisääntyneen tilastollisesti merkitsevästi. Tutkimuksessa saatiin uutta tietoa lasten PTG- ja LCR-tutkimusten oikeutusharkinnasta ja optimoinnista. Vaikka toiminta oli monin osin kansainvälisten suositusten mukaista, kuvaus-käytännön puutteita tuli esiin ja oikomishoidossa olevien lasten todettiin altistuvan jonkin verran tarpeettomasti säteilylle. Lisäksi selvisi, että koko hammashoitotiimin ja erityisesti ortodonttien ja apuoikojien tulee päivittää tietonsa lasten säteilysuojelusta ja tutustua uusiin sädealtistusta vähentäviin menetelmiin. Esiin nousi myös tarve kehittää tulevaisuudessa kuvauslaitteistoja, joissa kuvausala on nykyistä helpommin säädettävissä potilaan iän, koon ja kuvausindikaatioiden mukaisesti

Dentomaxillofacial imaging with panoramic views and cone beam CT

Panoramic and intraoral radiographs are the basic imaging modalities used in dentistry. Often they are the only imaging techniques required for delineation of dental anatomy or pathology. Panoramic radiography produces a single image of the maxilla, mandible, teeth, temporomandibular joints and maxillary sinuses. During the exposure the x-ray source and detector rotate synchronously around the patient producing a curved surface tomography. It can be supplemented with intraoral radiographs. However, these techniques give only a two-dimensional view of complicated three-dimensional (3D) structures. As in the other fields of imaging also dentomaxillofacial imaging has moved towards 3D imaging. Since the late 1990s cone beam computed tomography (CBCT) devices have been designed specifically for dentomaxillofacial imaging, allowing accurate 3D imaging of hard tissues with a lower radiation dose, lower cost and easier availability for dentists when compared with multislice CT. Panoramic and intraoral radiographies are still the basic imaging methods in dentistry. CBCT should be used in more demanding cases. In this review the anatomy with the panoramic view will be presented as well as the benefits of the CBCT technique in comparison to the panoramic technique with some examples. Also the basics as well as common errors and pitfalls of these techniques will be discussed. Teaching Points • Panoramic and intraoral radiographs are the basic imaging methods in dentomaxillofacial radiology.• CBCT imaging allows accurate 3D imaging of hard tissues.• CBCT offers lower costs and a smaller size and radiation dose compared with MSCT.• The disadvantages of CBCT imaging are poor soft tissue contrast and artefacts.• The Sedentexct project has developed evidence-based guidelines on the use of CBCT in dentistry.Peer reviewe

Minimum size and positioning of imaging field for CBCT-scans of impacted lower third molars : a retrospective study

Background Cone-beam Computed Tomography (CBCT) is widely used for preoperative 3D imaging of lower third molars. Hence, for this imaging indication, the present study aimed to define the minimum field-of-view (FOV) size and its optimum placement, to decrease radiation exposure, and highlight the need of computer-assisted FOV centering technique for dental CBCT devices. To facilitate proper placement of image field, lower second molar was chosen as reference. Methods The retrospective study included 50 CBCT-scans of 46 patients with mean age of 34 years. Based on the lower second molar, a three-dimensional coordinate was formed and the location of mandibular canal (MC) and the dimensions and locations of the lower third molars, and possible associated pathological findings were assessed. Accordingly, the FOV size and position for third-molar imaging were optimized, while ensuring encompassment of all relevant structures. Results The minimum cylindrical volume, covering lower third molars and MC, was 32.1 (diameter) x 31.6 (height) mm, placed in relation to the second molar crown, top 2.2 mm above cusp tips, anterior edge 6.7 mm in the front of the most distal point of the crown, and lingual edge 7.9 mm on the medial side of the lingual wall. Conclusions The optimized FOV for lower third molars was smaller than common standard small FOVs. We recommend using FOV volume 3.5 null x 3.5 cm for third molars without associated pathology. Accurate FOV protocols are essential for development of new CBCT-devices with computer-assisted and indication-specific FOV placement.Peer reviewe

Minimum size and positioning of imaging field for CBCT scans of impacted maxillary canines

Objectives In children and adolescents, cone-beam computed tomography (CBCT) is frequently used for localization of unerupted or impacted teeth in the anterior maxilla. CBCT causes a higher radiation dose than conventional intraoral and panoramic imaging. The objective was to analyze the location of impacted canines in a three-dimensional coordinate and thereby optimize the CBCT field-of-view (FOV), for radiation dose reduction. Materials and methods Location of 50 impacted maxillary canines of children under 17 years was retrospectively evaluated from CBCT scans. The minimum and maximum distances of any part of the right- and left-side canines to three anatomic reference planes were measured to assess the adequate size and position of a cylindrical image volume. Results A cylinder sized 39.0 (diameter)x33.2 (height) mm, with its top situated 13.8 mm above the hard palate, its medial edge 8.4 mm across the midline, and anterior edge 2.5 mm in front of the labial surface of maxillary central incisors fitted all the analyzed canines. Conclusions In this sample, the FOV required for imaging maxillary impacted canines was smaller than the smallest FOV offered by common CBCT devices. We encourage development of indication-specific CBCT imaging programs and aids to facilitate optimum patient positioning.Peer reviewe

Minimum size and positioning of imaging field for CBCT-scans of impacted lower third molars: a retrospective study

Background: Cone-beam Computed Tomography (CBCT) is widely used for preoperative 3D imaging of lower third molars. Hence, for this imaging indication, the present study aimed to define the minimum field-of-view (FOV) size and its optimum placement, to decrease radiation exposure, and highlight the need of computer-assisted FOV centering technique for dental CBCT devices. To facilitate proper placement of image field, lower second molar was chosen as reference.Methods: The retrospective study included 50 CBCT-scans of 46 patients with mean age of 34 years. Based on the lower second molar, a three-dimensional coordinate was formed and the location of mandibular canal (MC) and the dimensions and locations of the lower third molars, and possible associated pathological findings were assessed. Accordingly, the FOV size and position for third-molar imaging were optimized, while ensuring encompassment of all relevant structures.Results: The minimum cylindrical volume, covering lower third molars and MC, was 32.1 (diameter) × 31.6 (height) mm, placed in relation to the second molar crown, top 2.2 mm above cusp tips, anterior edge 6.7 mm in the front of the most distal point of the crown, and lingual edge 7.9 mm on the medial side of the lingual wall.Conclusions: The optimized FOV for lower third molars was smaller than common standard small FOVs. We recommend using FOV volume 3.5∅ × 3.5 cm for third molars without associated pathology. Accurate FOV protocols are essential for development of new CBCT-devices with computer-assisted and indication-specific FOV placement.</p

A point-of-care test of active matrix metalloproteinase-8 predicts triggering receptor expressed on myeloid cells-1 levels in saliva

Background This cross-sectional study aims to investigate if a point-of-care (PoC) test of active matrix metalloproteinase-8 (aMMP-8) predicts levels of inflammation amplifier triggering receptor expressed on myeloid cells-1 (TREM-1) and its putative ligand the neutrophil peptidoglycan recognition protein 1 (PGLYRP1) in saliva. Methods Forty-seven adolescents, aged 15 to 17 years, were tested with aMMP-8 PoC test, which was followed by a full-mouth clinical examination of the assessment of periodontal, mucosal, and oral health. TREM-1 and PGLYRP1 levels were analyzed by ELISA. The immunofluorometric assay (IFMA) specific for aMMP-8 was used as the reference method. Results Fourteen saliva samples out of a total of 47 showed positivity for aMMP-8 PoC test. Both the TREM-1 and the aMMP-8 (IFMA) levels were significantly elevated among the aMMP-8 PoC test positives compared with the PoC test negatives (P = 4 mm was significantly lower among the adolescents that had a negative aMMP-8 PoC test result, and TREM-1 levels = 4 mm (P <0.001). Conclusion The present study validated usability of aMMP-8 PoC test for predicting "proinflammatory" salivary profile and periodontal health status in adolescents.Peer reviewe

The effect of optimum, indication-specific imaging fields on the radiation exposure from CBCT examinations of impacted maxillary canines and mandibular third molars

Objective Indication-specific optimum field-of-views (FOVs) have been assessed for CBCT scans of impacted maxillary canines and mandibular third molars, as 40 null x 35 mm and 35 null x 35 mm, respectively. The objective was to investigate possible changes in absorbed organs and effective doses, for these two imaging indications, performing CBCT examinations with optimum FOV sizes instead of commonly used FOVs. Additionally, radiation exposure-induced cancer risk was calculated for both imaging indications with optimum FOVs.Methods An adult female head phantom (ATOM 702-D, CIRS, Norfolk, VA, USA) was scanned using Planmeca Viso G7 CBCT-device (Planmeca, Helsinki, Finland). Scanning factors, different FOV sizes, dose-area product (DAP) values and anatomical FOV locations were used for Monte Carlo PCXMC-simulation and ImpactMC software. In the PCXMC- simulation, 10-year-old child and 30-year-old adult phantoms were used to estimating effective and absorbed organ doses.Results The effective dose varied from 58 mu Sv to 284 mu Sv for impacted maxillary canines, and from 38 mu Sv to 122 mu Sv for mandibular third molars, the lowest dose value for each corresponding to optimum FOV. Effective dose reduction between the optimum FOV and the smallest common FOV of 50 null x 50 mm, maintaining other scanning factors constant, was 33% for impacted maxillary canines, and 45% for mandibular third molars. At all examinations, the highest absorbed organ doses were in salivary glands or in oral mucosa.Conclusions Optimum FOVs, 40 null x 35 mm for impacted maxillary canine and 35 null x 35 mm for mandibular third molar, could decrease effective doses received by young patients, and improve radiation safety in these common CBCT imaging procedures.Peer reviewe