Magister Scientiae Dentium - MSc(Dent) / Aim: Analysis of the occurrence of taurodont molars among patients attending the Tygerberg Oral Health Centre. Methodology: A retrospective descriptive study comprising 1608 panoramic radiographs of patient records, 815 females and 793 males, ranging in ages from 18 to 68 years old. The panoramic radiographs were evaluated for presence of taurodontism. Gender predilection and location of taurodont molars were analysed using a chi-square test. Results: Taurodontism was found in 52 (3.23%) radiographs distributed according to gender (30 females and 22 males [P > 0.05]). The overall prevalence of taurodont molars was (0.73%) from a total of 17148 molars that were examined. The mandibular molar teeth were more affected than the maxillary molar teeth and the second mandibular tooth was the most affected. Conclusion: Taurodontism was not uncommon in a group of patients that attended the Tygerberg Oral Health Centre, UWC. Further larger scale studies are required to assess its distribution in the general population of South Africa to compare it with other ethnic groups and to establish any associations. However, taurodontism in mandibular teeth is a condition that should be taken into consideration, especially the second mandibular tooth, to avoid complications.

>Magister Scientiae - MSc / Different pathology associated with impacted wisdom teeth in the oral cavity showed that it is prevalent and may lead to varied dental complications. This study adopted a descriptive cross-sectional retrospective analytical design in order to examine hard tissue features associated with the presence of impacted third molars in a random sample of 2998 digital panoramic radiographs (DPRs) of patients' records in Tygerberg Oral Health Centre, Faculty of Dentistry, University of Western Cape. The specific objectives of the study were to categorize the type of impactions in the DPRs of patients and to determine the prevalence of distal cervical caries (DCC) in second molars, any radiolucent (RL) /radiopaque (RO) lesions or external root resorption (ERR) complications associated with impacted wisdom teeth. Results of the pantomographs and clinical records of patients indicated that the most prevalent type of impaction (TOI) is Mesioangular (MA) Impaction (65%) followed by Horizontal (H) Impaction (17%), Vertical (V) Impaction (15%), Transverse (TVS) Impaction (2 %) and Distoangular (DA) Impaction (1.2 %), respectively. The least prevalent type was Inverted (INV) Impaction with a frequency count of 0.5%. The results further indicated varied dental complications resulting from impaction, ranging from ERR with a frequency of 3% of which 66.70% was associated with MA type of impaction, followed by H with a frequency of 26.7%. The association of Gender and RL/ RO lesions was significant (p-value=0.04) while association between DCC and types of impaction was also significant (p-value =0.0017). The study concluded that the high prevalence of MA among all populations and genders over the years may be related to the anatomical normal inclination of the third molars to the mesial surface. The low prevalence of DA observed in the study sample on the other hand might be attributable to gender and demographic factors. Lastly, this study has only one radiopaque lesion and the high prevalence of RL lesions in males and in the older age group suggests that these complications take a while to develop. Future research is needed to raise more awareness and encourage patients to seek treatment of symptomatic and asymptomatic third molars before complications arise.

The age estimation method as described by Demirjian is the most frequently used tool to estimate the sub-adult dental age in forensic dentistry. This technique has been shown to over or under estimate the chronological age of sub-adults when applied to specific population groups. The aim of this study was to compare a black South African population sample with the original French-Canadian model to determine if Demirjian’s method accurately reflects the true chronological age of this population group. A sample of panoramic radiographs from 279 boys and 325 girls between the ages of 6 and 16 was obtained from the School of Dentistry University of Pretoria, and from orthodontists in private practice in the Pretoria region. The panoramic radiographs were used to score the seven left mandibular teeth. The calculated maturity score was used to determine the Demirjian dental age. All panoramic radiographs were scored by one examiner. A subset of 20 panoramic radiographs was scored by a second examiner and reliability tested using a Wilcoxon Matched Pairs Test. This research showed that black South African children have a more advanced dental age compared to French-Canadian children. Demirjian overestimated the age for boys by 0.8 years and for girls by 0.5 years. The dental age assessment provided by Demirjian is not suitable for black South African children. As a result, new standards of dental age assessment should be established for this population. Copyright / Dissertation (MSc(Odont))--University of Pretoria, 2011. / Oral Pathology and Oral Biology / unrestricted

O objetivo deste estudo foi avaliar, por meio das radiografias panorâmicas, o comportamento longitudinal da inclinação axial mesiodistal dos molares superiores decorridos cinco anos após o tratamento realizado com o aparelho Pendulum seguido de aparelhagem ortodôntica fixa e comparar os resultados com os valores médios normais. A amostra consistiu de 20 pacientes (14 do gênero feminino e 6, do masculino) com má oclusão de Classe II tratada por meio da distalização dos molares superiores. A média da idade, ao início do tratamento (T1), foi de 14,27 ± 1,62 anos, ao final do tratamento (T2), 18,59 ± 1,82 anos, e, cinco anos pós-tratamento (T3), 23,77 ± 2,04 anos. A média do tempo de tratamento foi de 4,36 ± 0,79 anos e de avaliação pós-tratamento foi de 5,18 ± 1,14 anos. Como grupo controle, utilizou-se os valores angulares médios normais de molares superiores obtidos por Ursi (1989), sendo que essa obtenção partiu de radiografias panorâmicas de indivíduos com oclusão normal apresentando idades entre 12 e 17 anos. Para a análise estatística, utilizaram-se os traçados das radiografias panorâmicas nas 3 fases (T1, T2 e T3). Os dados obtidos foram analisados estatisticamente pelo teste ANOVA dependente seguido do teste de Tukey. As médias das inclinações axiais mesiodistais nas fases T1, T2 e T3 foram comparadas com os valores médios normais pelo teste t independente. Os resultados apontaram que os primeiros molares superiores, ao término do tratamento ortodôntico, estavam mais inclinados para a distal, porém, cinco anos após, tenderam a verticalizarem-se naturalmente, voltando a ocupar uma posição próxima ao inicial. Quando comparados com os valores normais, somente o primeiro molar superior esquerdo apresentou, no período T2, valor estatisticamente significante diferente do normal. Os valores correspondentes para os segundos molares superiores não apresentaram estatisticamente significantes quando comparados entre si, nem quando comparados com os valores normais. O tratamento com o Pendulum seguido de aparelhagem ortodôntica fixa promove uma inclinação das coroas dos molares para a distal, tendendo esses dentes, entretanto, no longo tempo pós-tratamento, a verticalizarem-se. / The objective of this study was to evaluate, through panoramic radiographs, the longitudinal conduct of mesiodistal inclination in maxillary molars five years after the treatment performed with the Pendulum device followed by fixed appliance and compare the results with normal mean values. The sample consisted of 20 patients (14 female and 6 male) with Class II malocclusion treated with molar distalization. The average age at pretreatment (T1) was 14.27 ± 1.62 years, at posttreatment (T2), 18.59 ± 1.82 years and at the long-term posttreatment (T3) 23.77 ± 2.04 years. The average length of time of the treatment was 4.36 ± 0.79 years and the evaluation of the long-term posttreatment was 5.18 ± 1.14 years. As a control, it was used the normal mean angular values of molar obtained by Ursi (1989), and this achievement came from panoramic radiographs of subjects with normal occlusion ranging in age from 12 to 17 years. Panoramic radiographs were taken for statistic analysis in all 3 stages (T1, T2, T3). The obtained data were statistically analysed through ANOVA Test dependent followed by Tukey test. The mean mesiodistal axial inclinations stages T1, T2, T3 were compared with normal mean values by the independent t test. The results showed that the first molars were more inclined to distal at posttreatment but five years later they tended to upright naturally, occupying the previous position, close to the original. When compared with normal values, only the left first maxillary molar showed in T2 a statistically different value to the normal. The correspondent values for the second maxillary molars did not show to be statistically significant when compared with each other, nor when compared with normal values. The treatment with the Pendulum, together with the orthodontic appliance, fosters an inclination of the molars to the distal, but tends to upright in the long-term posttreatment.

Magister Scientiae Dentium - MSc(Dent) (Community Oral Health) / The aim of this study was to establish whether there is any association between developing maxillary canine ectopia and various other dental anomalies using panoramic radiographs in the mixed dentition stage of development.

O objetivo deste estudo foi avaliar, por meio das radiografias panorâmicas, o comportamento longitudinal da inclinação axial mesiodistal dos molares superiores decorridos cinco anos após o tratamento realizado com o aparelho Pendulum seguido de aparelhagem ortodôntica fixa e comparar os resultados com os valores médios normais. A amostra consistiu de 20 pacientes (14 do gênero feminino e 6, do masculino) com má oclusão de Classe II tratada por meio da distalização dos molares superiores. A média da idade, ao início do tratamento (T1), foi de 14,27 ± 1,62 anos, ao final do tratamento (T2), 18,59 ± 1,82 anos, e, cinco anos pós-tratamento (T3), 23,77 ± 2,04 anos. A média do tempo de tratamento foi de 4,36 ± 0,79 anos e de avaliação pós-tratamento foi de 5,18 ± 1,14 anos. Como grupo controle, utilizou-se os valores angulares médios normais de molares superiores obtidos por Ursi (1989), sendo que essa obtenção partiu de radiografias panorâmicas de indivíduos com oclusão normal apresentando idades entre 12 e 17 anos. Para a análise estatística, utilizaram-se os traçados das radiografias panorâmicas nas 3 fases (T1, T2 e T3). Os dados obtidos foram analisados estatisticamente pelo teste ANOVA dependente seguido do teste de Tukey. As médias das inclinações axiais mesiodistais nas fases T1, T2 e T3 foram comparadas com os valores médios normais pelo teste t independente. Os resultados apontaram que os primeiros molares superiores, ao término do tratamento ortodôntico, estavam mais inclinados para a distal, porém, cinco anos após, tenderam a verticalizarem-se naturalmente, voltando a ocupar uma posição próxima ao inicial. Quando comparados com os valores normais, somente o primeiro molar superior esquerdo apresentou, no período T2, valor estatisticamente significante diferente do normal. Os valores correspondentes para os segundos molares superiores não apresentaram estatisticamente significantes quando comparados entre si, nem quando comparados com os valores normais. O tratamento com o Pendulum seguido de aparelhagem ortodôntica fixa promove uma inclinação das coroas dos molares para a distal, tendendo esses dentes, entretanto, no longo tempo pós-tratamento, a verticalizarem-se. / The objective of this study was to evaluate, through panoramic radiographs, the longitudinal conduct of mesiodistal inclination in maxillary molars five years after the treatment performed with the Pendulum device followed by fixed appliance and compare the results with normal mean values. The sample consisted of 20 patients (14 female and 6 male) with Class II malocclusion treated with molar distalization. The average age at pretreatment (T1) was 14.27 ± 1.62 years, at posttreatment (T2), 18.59 ± 1.82 years and at the long-term posttreatment (T3) 23.77 ± 2.04 years. The average length of time of the treatment was 4.36 ± 0.79 years and the evaluation of the long-term posttreatment was 5.18 ± 1.14 years. As a control, it was used the normal mean angular values of molar obtained by Ursi (1989), and this achievement came from panoramic radiographs of subjects with normal occlusion ranging in age from 12 to 17 years. Panoramic radiographs were taken for statistic analysis in all 3 stages (T1, T2, T3). The obtained data were statistically analysed through ANOVA Test dependent followed by Tukey test. The mean mesiodistal axial inclinations stages T1, T2, T3 were compared with normal mean values by the independent t test. The results showed that the first molars were more inclined to distal at posttreatment but five years later they tended to upright naturally, occupying the previous position, close to the original. When compared with normal values, only the left first maxillary molar showed in T2 a statistically different value to the normal. The correspondent values for the second maxillary molars did not show to be statistically significant when compared with each other, nor when compared with normal values. The treatment with the Pendulum, together with the orthodontic appliance, fosters an inclination of the molars to the distal, but tends to upright in the long-term posttreatment.

Abstract Today, digital imaging is widely used in dentistry. In medical radiography, the importance of displays and room illuminance has been shown in many studies, whereas the effect of these factors in the diagnosis of dental radiography is not clear and remains controversial. There is limited knowledge among dentists as to how observer performance is affected by the type of display, level of ambient light or grayscale calibration. The aim of this thesis was to compare observer performance in the detection of both anatomical structures and pathology in panoramic and bitewing radiographs using consumer grade display with γ 2.2- and DICOM-calibration, a tablet (3rd generation Apple iPad® and a 6 MegaPixel (MP) display under different lighting conditions. Furthermore, the thesis aimed at providing recommendations for type of display and acceptable illuminance levels in the room for interpretation of dental radiographs. Thirty panoramic and bitewing radiographs were randomly evaluated on four displays under bright (510 lx) and dim (16 lx) ambient lighting by two observers. Both anatomical structures and pathology were evaluated because they provided both low- and high-contrast structure. Consensus was considered as reference. Intra- and inter-observer agreement was determined. The proportion of equivalent ratings and weighted kappa were used to assess the reliability. The level of significance was set to P<0.05. DICOM calibration may improve observer performance in the detection of pathology in panoramic radiographs regardless of the room illuminance level. DICOM calibration improves the detection of enamel and dentinal caries in bitewing radiographs, particularly in bright lighting conditions. On the other hand, in dental practice the room illuminance level is often higher, and it is thus recommended that the overall lighting level should be decreased. Furthermore, a DICOM-calibrated consumer grade display can be used instead of a medical display in dental practice without compromising the diagnostic quality and it saves costs. Tablet displays are recommended to use with care in dental radiography. / Tiivistelmä Hammaslääketieteessä käytetään nykyään pääasiassa digitaalista kuvantamista. Lääketieteellisessä radiologiassa näyttöjen ja käyttöympäristön valaistuksen merkitys kuvien katseluun on osoitettu lukuisissa tutkimuksissa, kun taas hammaslääketieteellisten tutkimusten tulokset näiden tekijöiden vaikutuksista röntgenkuvien tulkintaan eivät ole yksiselitteisiä ja niissä on ristiriitaisuutta. Hammaslääkäreiden tiedot näyttöjen, kalibroinnin ja ympäröivän valaistuksen vaikutuksesta röntgenkuvan tulkintaan ovat puutteellisia. Tämän väitöskirjan tarkoituksena oli vertailla näyttöjen suorituskykyä panoraama- ja purusiivekekuvien tulkinnassa eri valaistusolosuhteissa. Tutkimuksessa vertailtiin γ 2.2- ja DICOM-kalibroitua perusnäyttöä, tablettia (kolmannen polven Apple iPad®) sekä 6 MegaPikselin (MP) lääketieteelliseen käyttöön tarkoitettua näyttöä. Lisäksi väitöskirjan tarkoituksena oli antaa hammaslääketieteellisten röntgenkuvien katseluun soveltuvia näyttöjä ja käyttöympäristön valaistusta koskevia suosituksia. Kaksi tulkitsijaa arvioi 30 panoraama- ja purusiivekeröntgenkuvaa satunnaisessa järjestyksessä neljältä eri näytöltä kirkkaassa (510 luksia) ja hämärässä (16 luksia) valaistuksessa. Tutkimuksessa arvioitiin sekä korkeakontrastisia anatomisia rakenteita että matalakontrastisia patologisia löydöksiä. Tuloksia verrattiin tutkijoiden väliseen yhteisluentaan. Luotettavuuden arviointiin käytettiin yhdenmukaisuusosuutta sekä painotettua kappaa. Toistettavuuden arvioimiseksi laskettiin kapat toisen alkuperäisten ja uusintaluentojen sekä molempien tulkitsijoiden alkuperäisluentojen välille. Merkitsevyystasoksi määriteltiin p<0,05. DICOM-kalibrointi voi parantaa patologisten löydösten tulkintaa panoraamakuvissa molemmissa valaistusolosuhteissa. DICOM-kalibrointi parantaa selvästi purusiivekekuvien hammaskiille- ja hammasluukarieksen tulkintaa erityisesti kirkkaassa valaistuksessa. Hammaslääkäreiden työskentelytilojen valaistus on yleensä korkeampi kuin tutkimuksessa käytetty, joten näyttöjen käyttöympäristön valaistusta tulisi laskea toimistovalaistusta vastaavaksi. DICOM-kalibroitua perusnäyttöä voidaan suositella käytettäväksi kalliiden medikaalinäyttöjen sijaan. Tablettia tulee sen sijaan käyttää harkiten hammaskuvien tulkintaan.

Magister Scientiae - MSc / Nowadays, the availability of radiographic modalities from conventional radiography to more advanced approaches such as medical computed tomography as well as cone beam computed tomography have been useful in providing insights of relevant anatomy prior to surgical procedures. The increased popularity of cone beam computed tomography has prompted interest in the utility of this approach for diagnostic application in dentistry, including the assessment of the proximity of impacted mandibular third molars to the inferior alveolar canal. It is important to understand the reliability of conventional panoramic radiograph in the assessment of this criterion since it is more commonly used as first line radiographic approach due to its availability and lower radiation dose. This study is aimed to investigate the reliability of conventional panoramic radiograph in the evaluation of the proximity of impacted mandibular third molar root tip to the inferior alveolar canal by correlating the results with cone beam computed tomography. A retrospective study of forty nine patients who underwent panoramic radiography as well as cone beam computed tomography for examination of impacted mandibular third molars was conducted. Two observers were participated in all image evaluation. In this study, both observers recorded statistically significant differences in the measurement of the apices of vertically impacted third molars and the inferior alveolar canal from panoramic radiographs and cone beam computed tomography images. The low reliability of panoramic radiograph to assess the vertical proximity between these two anatomical structures suggests the importance of additional assessment with cone beam computed tomography in cases where panoramic radiograph shows superimposition of the third molar root on the roof of the canal, presence of root below the roof of the canal and presence of bone height of less than one millimetre separating the third molar from the inferior alveolar canal.

Carotid stenosis is one of several causes of ischemic stroke and entails a high risk of ischemic stroke recurrence. Removal of a carotid stenosis by carotid endarterectomy results in a risk reduction for ischemic stroke, but the magnitude of risk reduction depends on several factors. If the delay between the last symptom and carotid endarterectomy is less than 2 weeks, the absolute risk reduction is >10%, regardless of age, sex, or if the degree of carotid stenosis is 50–69% or 70–99%. Thus, speed is the key. However, if many patients suffers an ischemic stroke recurrence within the first 2 weeks of the presenting event, an additional benefit is likely be obtained if carotid endarterectomy is performed even earlier than within 2 week after the presenting event. Carotid endarterectomy for asymptomatic carotid stenoses carries a small risk reduction for stroke. Screening for asymptomatic carotid stenosis requires a prevalence of >5% in the examined population, i.e., higher than in the general population; however, directed screening in groups with a prevalence of >5% is beneficial. The aims of this thesis were to investigate the length of the delay to carotid endarterectomy, determine the risk of recurrent stroke before carotid endarterectomy, and determine if a calcification in the area of the carotid arteries seen on dental panoramic radiographs is a valid selection method for directed ultrasound screening to detect asymptomatic carotid stenosis. Consecutive patients with a symptomatic carotid stenosis who underwent a preoperative evaluation aimed at carotid endarterectomy at Umeå Stroke Centre between January 1, 2004–March 31, 2006 (n=275) were collected retrospectively and between August 1, 2007–December 31, 2009 (n=230) prospectively. In addition, 117 consecutive persons, all preliminarily eligible for asymptomatic carotid endarterectomy and with a calcification in the area of the carotid arteries seen on panoramic radiographs, were prospectively examined with carotid ultrasound. The median delay between the presenting event and carotid endarterectomy was 11.7 weeks in the first half year of 2004, dropped to 6.9 weeks in the first quarter year of 2006, and had dropped to 3.6 weeks in the second half year of 2009. The risk of ipsilateral ischemic stroke recurrence was 4.8% within 2 days, 7.9% within 1 week, and 11.2% within 2 weeks of the presenting event. For patients with a stroke or transient ischemic attack as the presenting event, this risk was 6.0% within 2 days, 9.7% within 1 week, and 14.3% within 2 weeks of the presenting event. For the 10 patients with a near-occlusion, the risk of ipsilateral ischemic stroke recurrence was 50% at 4 weeks after the presenting event. Among the 117 persons with a calcification in the area of the carotid arteries seen on panoramic radiographs, eight had a 50–99% carotid stenosis, equalling a prevalence of 6.8% (not statistically significantly over the pre-specified 5% threshold). Among men, the prevalence of 50–99% carotid stenosis was 12.5%, which was statistically significantly over the pre-specified 5% threshold. In conclusion: The delay to carotid endarterectomy was longer than 2 weeks. Additional benefit is likely to be gained by performing carotid endarterectomy within a few days of the presenting event instead of at 2 weeks because many patients suffer a stroke recurrence within a few days; speed is indeed the key. The finding that near-occlusion entails an early high risk of stroke recurrence stands in sharp contrast to previous studies; one possible explaination is that this was a high-risk period missed in previous studies. The incidental finding of a calcification in the area of the carotid arteries on a panoramic radiograph is a valid indication for carotid ultrasound screening in men who are otherwise eligible for asymptomatic carotid endarterectomy.

El estudio tuvo como objetivo determinar la prevalencia del fallo primario de la erupción dental en radiografías panorámicas de un centro imagenológico, Chiclayo, 2023. Este estudio fue descriptivo, retrospectivo, observacional y transversal. Se analizaron las radiografías panorámicas de 220 pacientes de 11 a 15 años de edad, de ambos sexos, que presentaban al menos una primera molar permanente, que corresponden al año 2022. Según sexo 125 radiografías fueron de sexo masculino y 95 de sexo femenino. Se obtuvo, una prevalencia total de fallo primario de erupción de 0.91%, de los cuales 0,45% corresponde a cada sexo. Respecto a edad se encontró mayor predominancia en la edad de 14 años con un porcentaje del 1%, finalmente en la prevalencia según pieza dentaria se observó mayor incidencia de la pieza dentaria 85 en el 50% del total. Se concluyó que la prevalencia del fallo primario de la erupción dental alcanzó un nivel muy bajo, similar a otros estudios previos. / The study aimed to determine the prevalence of primary failure of dental eruption in panoramic radiographs of an imaging center, Chiclayo, 2023. This study was descriptive, retrospective, observational and cross-sectional. Panoramic radiographs were analyzed in 220 patients aged 11 to 15 years, of both sexes, who had at least one permanent first molar, corresponding to the year 2022. According to sex 125 x-rays were male and 95 female. A total prevalence of primary eruption failure of 0.91% was obtained, of which 0.45% corresponds to each sex. Regarding age, we found greater predominance in the age of 14 years with a percentage of 1%, finally in the prevalence according to tooth was observed greater incidence of the 85th tooth in 50% of the total. It was concluded that the prevalence of primary failure of dental eruption reached a very low level, similar to other previous studies.