Objective: To train and validate a deep learning-based diagnostic tool capable of accurately segmenting the alveolar cleft region and automatically estimating the required bone graft volume using cone-beam computed tomography (CBCT) imaging.

Study Design: Eighty-eight CBCT scans from patients with non-syndromic unilateral clefts were divided into training (n = 45), validation (n = 10), and test (n = 33) sets. Two annotators performed manual segmentations, and the intersection of these served as the ground truth for training 3D U-Net models. The Dice Similarity Coefficient (DSC) was calculated to validate the tool by comparing manual and automated segmentations. Three observers evaluated the resulting deep learning model using 33 CBCT scans and performing subjective assessments in terms of shape and size.

Results: The DSC between the two annotators was 0.66, and between the automated and manual segmentations, 0.78. The observers considered the automated segmentations acceptable in 82%–94% of the cases. The deep learning-based tool took approximately 7 seconds to perform an automated segmentation, while manual segmentation by the annotators required 14 and 6.5 minutes.

Conclusion: The deep learning-based tool that was developed in the present study can accurately perform automated segmentations of unilateral alveolar clefts and estimate the required bone graft volume.

Children are more sensitive to ionising radiation than adults due to the higher susceptibility of developing organs and tissues, including sensitive organs such as the thyroid gland, which is more easily exposed to radiation on account of children’s smaller head size. The greater number of remaining life years of young persons means that the risk of cumulative exposure is also greater. Children and youth with special healthcare needs (CYSHCN) often require more frequent examinations, which can result in higher exposure to ionising radiation. This thesis focuses on two groups of CYSHCN, those born preterm and those with orofacial clefts.

Preterm-born children account for about 5% of all children born in Sweden each year. The consequences of preterm birth can lead to higher exposure to ionising radiation due to healthcare-related examinations. However, knowledge on whether dental care also contributes to higher exposure, which Paper I analysed, is sparse. A retrospective study, Paper I retrieved the dental records of 311 preterm- and full term-born children and adolescents. No findings of significant differences in number of dental care-related radiographic examinations were found between the two groups. Additionally, although dental behaviour management problems during examinations and/or treatments in childhood were higher in the preterm group, this did not affect their dental status. Prevalence of caries and rate of referrals to a paediatric dental specialist were comparable between the two groups.

Orofacial clefts are among the most common congenital anomalies, with a prevalence of 2 in 1000 live births. Alveolar bone grafting is a surgical procedure, typically performed when the child is between 9 and 12 years of age, in which autogenous bone grafts are transplanted into the cleft area. Radiographic examinations are required before and after alveolar bone grafting, and cone-beam computed tomography (CBCT) is one of the imaging methods that can be used.

Segmentation of the cleft area can be done using CBCT imaging, offering a clear visualisation of the cleft and enabling estimation of the amount of bone graft required preoperatively. Paper II demonstrated this through semi-automated segmentations of 53 CBCT scans of uni- and bilateral clefts. Moreover, CBCT provided important information about the impact of the cleft on surrounding anatomical structures.

Both manual and semi-automated segmentation require the operator to delineate the cleft area in each CBCT slice, a process that is time-consuming and demands advanced software skills. Artificial intelligence is increasingly being incorporated into healthcare and may be useful in addressing these challenges. Thus, Paper III developed a deep learning tool and tested automated segmentation of unilateral clefts. In all, 88 CBCT scans were used for this purpose. The deep learning tool was found to be capable of accurately segmenting the cleft area as well as estimating preoperative bone graft volume.

Low-dose CBCT protocols are an effective way of reducing radiation exposure. Paper IV tested such a protocol in postoperative radiographic assessment of 14 cleft cases. The low-dose protocol was found to provide adequate image quality; however, observers reported lower confidence in their evaluations compared to the standard-dose protocol.

Barn är känsligare för joniserande strålning än vuxna på grund av, bland annat, deras tillväxt av organ och vävnader och att de förväntas ha en längre tid kvar i livet. Deras mindre huvudstorlek gör också att till exempel sköldkörteln lättare hamnar inom exponerade områden inom ramen för odontologisk radiologi. Två olika barngrupper har inkluderats i denna avhandling: för tidigt födda barn, och barn födda med läpp-käk-gom-spalt (LKG).

Varje år föds drygt 5% av alla barn för tidigt i Sverige. Några av konsekvenserna för dessa barn brukar leda till en ökad mängd undersökningar inom sjukhusvården och därmed också en ökad mängd röntgenundersökningar. Det saknas dock kunskap om vilken roll tandvården bidrar till att öka mängden undersökningar med joniserande strålning, vilket analyserades i avhandlingens första delarbete. Journaler, 311 stycken, från tandvården i Skåne, Sverige, granskades. Resultatet visade att de för tidigt födda- inte exponerades för mer joniserade strålning än barn födda efter fullgången graviditet. Dock uppvisade många av barnen problem i samband med undersökningar och/eller behandlingar under uppväxten jämfört med fullgångna barn. De för tidigt födda hade i stort inte ett sämre oralt status, förekomsten av karies och antal remisser till specialister inom pedodonti var likvärdig jämfört med barn födda efter normal tid.

LKG är bland de vanligaste medfödda ansiktsmissbildningarna, med en prevalens på 2 per 1000 födslar i Sverige. Patienterna genomgår många olika behandlingar i tidig ålder. När barnen är mellan 9–12 år, utför man ett kirurgiskt ingrepp, en s.k. dentoalveolär bentransplantation, där spalten fylls ut och stängs. Röntgenundersökningar krävs både före och efter ingreppet, och cone-beam computed tomography (CBCT) är en av de metoderna som kan användas. CBCT- bilder kan användas för att tydliggöra spaltområde och ta fram tredimensionella (3D) modeller. Resultatet kan medverka till att en uppskattning av mängden ben, som behövs till operationen. I andra delarbetet, togs sådana 3D-modeller fram med hjälp av 53 CBCT-undersökningar av spalter som var antingen på en sida om mittlinjen, ensidiga eller på båda sidorna, dubbelsidiga spalter. Det konstateras också att CBCT kan ge ytterligare information om hur spalten påverkar de omgivande anatomiska strukturerna. Den manuella hanteringen av denna process är tidskrävande för tandläkaren som ska utföra det.

Artificiell intelligens (AI) har alldeles nyligen blivit mycket uppmärksammat. Det integrerar alltmer i olika delar av samhället och då även inom hälso- och sjukvård. Även inom tandvård är AI ett område där det bedrivs mycket forskning i nuläget. Ett djupinlärningsbaserat verktyg, AI, utvecklades och testades i det tredje delarbetet och totalt användes 88 CBCT-bilder. Resultaten visade att AI verktyget kunde avgränsa spaltområdet med hög noggrannhet samt uppskatta mängden ben som skulle behövas till en kommande bentransplantationen. Tidsbesparingen var tydlig.

Att minska stråldoser som ges till patienterna är en del av optimeringsprocessen som inom Europeiska unionen är ett lagstadgat krav för att försöka använda en så liten mängd joniserande strålning vid varje undersökningstillfälle. Att utarbeta och testa s.k. låg-dos CBCT protokoll är ett effektivt sätt att spara, minimera, strålningsdos till patienter. I det fjärde delarbetet testades ett sådant protokoll i den postoperativa röntgenundersökningen av 14 spaltfall. Det visade sig att protokollet gav tillräcklig bildkvalitet för en sådan bedömning.

As crianças são mais sensíveis à radiação ionizante do que os adultos, devido, entre outros fatores, aos seus órgãos e tecidos estarem em crescimento e à sua maior esperança de vida. Além disso, o tamanho reduzido da cabeça faz com que a glândula tiroideia esteja mais exposta à radiação durante os exames radiológicos dentários. Esta tese incluiu dois grupos de crianças: crianças prematuras e crianças com fenda lábio-palatina.

Anualmente, cerca de 5% das crianças na Suécia nascem prematuras. Esta condição leva frequentemente à necessidade de um maior número de exames médicos hospitalares e, consequentemente, a um maior número de exames radiológicos. No entanto, o contributo da Medicina Dentária para este aumento não é conhecido, um aspeto que foi abordado no primeiro trabalho da tese. Foram analisados 311 diários clínicos de clínicas de Medicina Dentária no Skåne, na Suécia. Os resultados indicaram que as crianças prematuras não apresentavam um estado de saúde oral inferior ao das crianças nascidas a termo, sendo a prevalência de cáries e o número de encaminhamentos para especialistas em Odontopediatria semelhantes.

A fenda lábio-palatina é uma das malformações congénitas da face mais comuns, com uma prevalência de aproximadamente 2 por cada 1000 nascimentos na Suécia. Estas crianças são submetidas a múltiplos tratamentos desde o nascimento. Entre os 9 e os 12 anos, realiza-se o enxerto ósseo alveolar para preencher e encerrar a fenda. Exames radiológicos são necessários tanto antes como após o procedimento cirúrgico, sendo a tomografia computorizada de feixe cónico (CBCT) um dos métodos disponíveis. As imagens de CBCT permitem visualizar a área da fenda, gerar modelos tridimensionais (3D) e estimar a quantidade de osso necessária para o enxerto ósseo alveolar. No segundo trabalho da tese, foram gerados modelos 3D a partir de 53 exames CBCT de fendas unilaterais e bilaterais. Constatou-se, igualmente, que as imagens de CBCT fornecem informação adicional sobre o impacto que a fenda tem nas estruturas anatómicas adjacentes. No entanto, a segmentação manual da área da fenda é um processo moroso.

A inteligência artificial (IA) tem recebido, nos últimos anos, grande atenção, assumindo um papel cada vez mais relevante em diversas áreas da sociedade, nomeadamente na saúde. A Medicina Dentária é uma das áreas em que a IA tem vindo a ser alvo de intensa investigação científica. No terceiro trabalho da tese, foi desenvolvida e testada, com recurso a 88 exames CBCT, uma ferramenta baseada em deep learning. Os resultados mostraram que a ferramenta de IA era capaz de delimitar a área da fenda com elevada precisão e rapidez, bem como estimar a quantidade de osso necessária para o enxerto ósseo alveolar.

A redução das doses de radiação ionizante administradas aos doentes é parte integrante do princípio da otimização, que na União Europeia constitui um requisito legal, com o objetivo de utilizar a menor dose possível de radiação ionizante em cada exame radiológico. O desenvolvimento e teste de protocolos de CBCT de baixa dose são uma estratégia eficaz para reduzir a exposição dos doentes à radiação ionizante. No quarto trabalho da tese, foi testado um protocolo CBCT de baixa dose na avaliação radiográfica realizada após o enxerto ósseo alveolar, em 14 casos de fenda lábio-palatina. Constatou-se que a qualidade de imagem do protocolo CBCT de baixa dose era suficiente para este tipo de avaliação no período pós-operatório.

OBJECTIVES: The aim of this study was to investigate whether a low-dose cone-beam computed tomography (CBCT) protocol provides diagnostically acceptable image quality for assessing bone healing after alveolar bone grafting.

MATERIAL AND METHODS: The study cohort comprised 11 patients (aged 7-14 years) with orofacial clefts who had undergone alveolar bone grafting at Skåne University Hospital in Malmö, Sweden. During the postsurgical follow-up at 6 months, each patient was assessed twice: once with a standard-dose CBCT protocol and once with a low-dose CBCT protocol, which in total corresponds to one CBCT examination made with the exposure settings recommended by the manufacturer. Among others, the assessed parameters included subjective image quality, as well as bone graft height, thickness, and integration.

RESULTS: No significant differences were found between the standard- and low-dose protocols for most parameters (p > 0.05). Exceptions included subjective image quality (one observer, p = 0.05) and confidence levels during the assessment (three observers, p = 0.01, 0.01, 0.02).

CONCLUSIONS: The low-dose protocol yielded adequate image quality for postoperative CBCT healing assessment in patients who have undergone alveolar bone grafting. However, the confidence level of observers during the assessment with the low-dose protocol was reduced. This study is registered on ClinicalTrials.gov (NCT06395077).

CLINICAL TRIAL REGISTRATION: This study is registered on ClinicalTrials.gov (NCT06395077).

Objectives: To determine pre-operative cleft volume and evaluate cleft´s impact on surrounding anatomical structures in children and adolescents with orofacial clefts using cone bean computed tomography (CBCT) imaging.

Methods: The present retrospective study retrieved CBCT examinations of 68 patients from a previous study. The examinations had been exposed either before (n = 53) or after (n = 15) alveolar bone grafting. Pre-operative volume of cleft was determined, and type and location were evaluated. Morphological changes on the adjacent anatomical structures, including the incisive foramen, the nasal septum and floor, and the inferior turbinate, were assessed.

Results: Mean bilateral cleft volume was 0.76 cm3, while mean unilateral cleft volume was 1.08 cm3; the difference was significant (p < 0.001). Variation in cleft volume, however, was large. The incisive foramen was not visible in the majority of cases with bilateral clefts (71%); the difference was significant (p = 0.001). In cases with unilateral clefts, the nasal septum in 87% was curved towards the cleft or graft side. Also, the mean size of the widest part of the inferior turbinate was 8.8 mm on the cleft or graft side and 10.4 mm on the non-cleft side. The difference was significant (p < 0.001).

Conclusions: When required, CBCT is a feasible method for quantitatively illustrating alveolar clefts and their impact on the morphological development of surrounding structures. Variation in cleft volume was large.

BACKGROUND: Preterm birth has been shown to cause various long-term health issues. Children who were born preterm have also been observed to have more dental behaviour management problems (DBMP) during dental examinations and treatment than children born full term. It is known that dental radiographic examinations can be uncomfortable and cause anxiety in paediatric patients. Thus, our aims were to retrospectively compare dental care related examinations and treatments carried out in three different age intervals (3-6 years, 7-12 years, and 13-19 years) among preterm- and full-term born children and adolescents.

METHODS: The present study included 311 patient files: 122 very preterm-born and 33 extremely preterm-born children and adolescents (&lt; 32 gestational weeks). A matched control group of 156 full term-born children and adolescents (≥ 37 gestational weeks) was analysed for comparison. Various factors, including DBMP, missed appointments, dental caries, and radiographic examinations, were retrieved from the dental records for three age intervals: 3-6 years, 7-12 years, and 13-19 years.

RESULTS: Extremely preterm-born children missed significantly more dental appointments and presented with more DBMP during dental examinations and treatment than full term-born children in the 3-6-year age group; the same was observed for the very preterm-born in the 7-12-year age group. No significant differences in DBMP during bitewing and periapical examinations or in number of bitewing, periapical and panoramic radiographs occurred between the groups in any age interval.

CONCLUSION: Preterm-born children and adolescents may need more flexibility in booking and receive reminders for scheduled visits with the general dental team. Due to the non-significant differences in dental care related oral examinations and treatments, the same dental care service may be applied to the preterm- and full-term born children and adolescents.