Cone-beam computed tomography imaging of dentoalveolar and mandibular fractures

Proposed Diagnostic Reference Levels in the Missouri/Southern Illinois Region Associated with Cone-beam Computed Tomography Use in Endodontics

INTRODUCTION

Diagnostic reference levels (DRLs) are intended to improve patient safety and ensure that patient ionizing radiation doses are as low as reasonably achievable. The purpose of this dosimetry study was to establish regional DRL levels for cone-beam computed tomography (CBCT) imaging for specialty endodontics. Another aim was to compare phantom-measured ionizing radiation dose index 1 (DI1) index doses to the manufacturer-provided dose area product (DAP) radiation output values for each of the CBCT machines studied, to ascertain their degree of correlation. DAP refers to the dose area product, a measure of radiation dose monitoring which represents the dose within the beam times the area within the beam at that position.

METHODS

A thimble ionization chamber and polymethyl methacrylate phantom were used to obtain DI1 values using the SEDENTEXTCT method from 21 different CBCT units. DRLs were calculated based on the 75th percentile (third quartile) of the median output values.

RESULTS

The proposed DRL from the CBCT units surveyed has a DAP value of 838 mGy cm2 and a DI1 value of 3.924 mGy. DAP versus DI1 values of 500.6 mGy cm2 versus 2.006 mGy, and 838 mGy cm2 versus 3.906 mGy represented the third quartile of the median values for the 4-cm × 4-cm and 5-cm × 5-cm field of views (FOVs), respectively.

CONCLUSIONS

The DI1 and DAP values strongly correlated when 3 outlier CBCT machines (J Morita Veraview X800) using a novel 360° (full rotation) acquisition mode were excluded. The importance of selectable exposure parameters as directly related to ionizing radiation output is illustrated among the CBCT units surveyed. Although the actual FOV that is selected is ultimately dictated by the specific clinical requirements, a 4-cm × 4-cm FOV is recommended for specialist endodontics practice, whenever clinically practical, based on the decreased ionizing radiation output, as compared to that from a 5-cm × 5-cm FOV.

The use of CBCT in orthodontics with special focus on upper airway analysis in patients with sleep-disordered breathing

Applications of cone-beam CT (CBCT) in orthodontics have been increasingly discussed and evaluated in science and practice over the last two decades. The present work provides a comprehensive summary of current consolidated practice guidelines, cutting-edge innovative applications, and future outlooks about potential use of CBCT in orthodontics with a special focus on upper airway analysis in patients with sleep-disordered breathing. The present scoping review reveals that clinical applications of CBCT in orthodontics are broadly supported by evidence for the diagnosis of dental anomalies, temporomandibular joint disorders, and craniofacial malformations. On the other hand, CBCT imaging for upper airway analysis-including soft tissue diagnosis and airway morphology-needs further validation in order to provide better understanding regarding which diagnostic questions it can be expected to answer. Internationally recognized guidelines for CBCT use in orthodontics are existent, and similar ones should be developed to provide clear indications about the appropriate use of CBCT for upper airway assessment, including a list of specific clinical questions justifying its prescription.

CBCT in contemporary endodontics

Cone-beam computed tomography (CBCT) is a three-dimensional imaging modality which can aid endodontic diagnosis and treatment planning. While there are guidelines available describing the indications, there are divergent philosophies on when this technology should be applied in clinical practice. This paper reviews the applications of CBCT including the clinical relevance of parameters which can be assessed, highlights the limitations of this technology, and provides guidance on how to maximise its clinical utility.

Accuracy and eligibility of Bonwill⁃Hawley arch form established by CBCT image for dental crowding measurement: a comparative study with the conventional brass wire and caliper methods

OBJECTIVES

The purpose of this study was to develop a novel Bonwill⁃Hawley method (Bonwill⁃Hawley arch form based on CBCT image) for the assessment of dental crowding, and to investigate and compare the accuracy and eligibility with the conventional brass wire and caliper methods under different crowding conditions.

MATERIAL AND METHODS

Sixty patients with the pair of plaster casts and CBCT data were collected. All the casts were marked and transformed into digital models using iTero scanner, and imported into OrthoCAD software to measure the required space. Using the conventional brass wire (M1) and caliper methods (M2), the available space and dental crowding were measured and calculated basing on digital models, respectively. Correspondingly, the axial planes in the level of dental arches were oriented and captured from the CBCT images to draw the Bonwill⁃Hawley arch forms (M3), which were used to measure and calculate the available space and dental crowding. For each method, intra and inter-examiner reliabilities were evaluated with intra-class correlation coefficients (ICCs). Wilcoxon test and Kruskal-Wallis test were performed for statistically analyzing the discrepancy among different groups.

RESULTS

Both intra- and inter-examiner reliability were generally excellent for all parameters obtained by the three methods, except for the dental crowding measured using M1(ICC: 0.473/0.261). The dental crowding measured using M2 were significantly increased in mild, moderate and severe-crowding groups compared with M1. However, no significant difference was detected between M1 and M3 in severe-crowding group (maxilla, p = 0.108 > 0.05; mandible, p = 0.074 > 0.05). With the deterioration of crowding condition, the discrepancy of dental crowding between M1 and M2, or M1 and M3 were significantly decreased (maxilla, M2-M1, mild VS serve, p = 0.003 < 0.05; maxilla, M3-M1, mild VS serve, p = 0.003 < 0.05; mandible, M2-M1, mild VS serve, p = 0.000 < 0.001; mandible, M3-M1, mild VS serve, p = 0.043 < 0.05).

CONCLUSION

Dental crowding measured using the novel Bonwill⁃Hawley method was relatively greater than the caliper method, but not exceeding the brass wire method, which wound gradually come close to the brass wire method with the deterioration of crowding condition.

CLINICAL RELEVANCE

The Bonwill⁃Hawley method basing on CBCT image proved to be a reliable and acceptable choice for orthodontists to analyze the dental crowding.

Retrospective Evaluation of Maxillofacial Fractures With Cone-Beam Computed Tomography

ÖZ Amaç: Bu çalışmanın amacı maksillofasiyal bölgede meydana gelen fraktürlerin yaş ve cinsiyete göre dağılımlarını, lokalizasyonlarını, sayısını, deplasman varlığını, radyolojik özelliklerini Konik Işınlı Bilgisayarlı Tomografi (KIBT) ile retrospektif olarak değerlendirmektir. Gereç ve Yöntemler: Zonguldak Bülent Ecevit Üniversitesi Diş Hekimliği Fakültesi, Ağız Diş ve Çene Radyolojisi Anabilim Dalı’na 2019 ve 2021 yılları arasında travma nedeniyle başvuran 84 hastadan alınan KIBT görüntüleri retrospektif olarak incelenmiştir. Yaş, cinsiyet, fraktür lokalizasyonu, fraktürlerde deplasman varlığı kayıt altına alındı. İstatistiksel analiz için tüm hasta grubuna tanımlayıcı ve frekans analizleri uygulanırken, hastaların yaş ve cinsiyetlerini; fraktür hattı ve fraktür bölgesi ile karşılaştırırken ki-kare testi uygulandı. Bulgular: 60 erkek 24 kadın hasta (E/K, 2,5/1) olmak üzere toplam 84 hastanın maksillofasiyal travma nedeniyle KIBT görüntüsü incelendi. Çalışmada incelenen hasta grubunun yaşları 6 ve 72 arasında değişmekte olup yaş ortalaması 33.17±1.48 olarak belirlendi. Farklı etiyolojik nedenlerden kaynaklı çeşitli lokalizasyonlarda meydana gelen 116 fraktür hattı sayısı radyolojik olarak tespit edildi. İncelenen tüm fraktürlerin 73’ünde deplasman izlenirken kalan 43 fraktür hattında deplasman görülmedi. Meydana gelen fraktürler en sık angulus mandibulada (%22,61:n=19) tespit edildi. En az fraktür mandibula ramus (%3,57; n=3) ve koronoid proseste (%3,57; n=3) görüldü. Sonuçlar: Fraktür hatlarının varlığının, lokalizasyonlarının ve kırık parçalarının yer değişiminin doğru radyografik teknikler aracılığıyla tespit edilmesi, gerekli tedavi prosedürlerinin uygulanması açısından önem taşımaktadır. İki boyutlu radyografilerin kullanımının yetersiz kaldığı durumlarda KIBT gibi üç boyutlu görüntüleme yöntemleri tercih edilmelidir. Anahtar Kelimeler: Konik Işınlı Bilgisayarlı Tomografi, Fraktür, Mandibula, Teşhis