Cork University Dental School and Hospital - Doctoral Theses

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    Impact of downward adjustment of water fluoride concentration on dental caries and fluorosis
    (University College Cork, 2022-12-20) James, Patrice; Whelton, Helen; Harding, Mairead; O’Mullane, Denis; Perry, Ivan J.; Cronin, Michael; Health Research Board
    Introduction: Community water fluoridation (CWF) was initiated in Ireland in 1964 at a concentration of 0.8 to 1 ppm fluoride. In 2007, in the context of ongoing reductions in dental caries with increasing prevalence and severity of dental fluorosis, water fluoride concentration in Ireland was adjusted to 0.6 to 0.8 ppm with the aim of reducing the prevalence and severity of dental fluorosis while maintaining reductions in dental caries. Aim: To determine the difference in dental caries and fluorosis levels following downward adjustment of CWF concentration. Methods: Ethical approval was obtained from the Clinical Research Ethics Committee (CREC) of the Cork Teaching Hospitals. A before and after study compared dental caries and fluorosis in random samples of 8-year-olds in Dublin (n=707) and Cork-Kerry (n=1,148) in 2016-17 with 8-year-olds in Dublin (n=679) and Cork-Kerry (n=565) in 2002. Dentinal caries experience in primary teeth (d3vcmft(cde)) and fluorosis in permanent teeth (Dean’s Index, whole mouth score) were clinically measured by trained and calibrated dentists. Standardised oral photographs were taken (8 seconds drying) for children in Cork-Kerry in 2016-17 and 2002. Fluorosis (Thylstrup-Fejerskov (TF) Index) in permanent maxillary central incisors was scored from the photographs in duplicate by two trained and calibrated dentists, blind to fluoridation status and year, with disagreements resolved by consensus. Person-level TF score was the highest score in the central incisors. Children were categorised as having lifetime or no exposure to CWF (Full-CWF/No-CWF). Effect of examination year on dental caries prevalence (d3vcmft(cde) > 0) and severity (mean d3vcmft(cde) among children with caries experience) and fluorosis prevalence (Dean’s ‘very mild’ or greater, TF 1 or greater and TF 2 or greater) were evaluated using multivariable regression controlling for the effects of other explanatory variables. Additional multivariable regression analyses evaluated the effect of CWF on dental caries prevalence and severity and fluorosis prevalence in 2002 and 2016-17, before and after the downward adjustment, respectively. Results: After controlling for the effects of other explanatory variables, children in Cork-Kerry in 2016-17, with lifetime exposure to CWF at 0.6 to 0.8 ppm fluoride, had lower caries prevalence (56% vs. 65%) and severity (mean d3vcmft(cde) 3.7 vs. 4.2) in primary teeth than their counterparts with No-CWF. Among children with Full-CWF, there was no statistically significant difference in caries prevalence or severity between 2002 and 2016-17. In 2016-17, caries prevalence was 55% in Dublin (Full-CWF) and 56% in Cork-Kerry (Full-CWF) and mean d3vcmft(cde) among children with caries was 3.4 and 3.7, respectively. Among children with No-CWF, caries severity was less in 2016-17 (mean 4.2) than 2002 (mean 4.9) (P = 0.039). The difference in caries severity between children with Full-CWF and No-CWF was less in 2016-17 than 2002 (Interaction P = 0.013), suggesting a reduced benefit for CWF in 2016-17. In 2016-17, fluorosis prevalence (Dean’s Index) was 18% in Dublin (Full-CWF) and 12% in Cork-Kerry (Full-CWF). Fluorosis was predominantly ‘very mild’ with no statistically significant difference between 2002 and 2016-17. Fluorosis prevalence in permanent maxillary central incisors was predominantly TF 1 and TF 2 and was lower in Cork-Kerry in 2016-17 than in 2002 at both case definitions. Among children with Full-CWF, prevalence of TF 1 or greater was 40% in 2016-17 and 75% in 2002 (OR 0.24, 95% CI [0.17, 0.34], P < 0.001) and prevalence of TF 2 or greater was 15% in 2016-17 and 27% in 2002 (OR 0.50, 95% CI [0.33, 0.75], P = 0.001). At both time points, fluorosis prevalence measured using Dean’s Index and the TF Index was higher among children with Full-CWF than their counterparts with No-CWF (2002 and 2016-17, P < 0.001). Conclusion: There was no reduction in fluorosis prevalence measured clinically using Dean’s Index in 2016-17 compared with 2002. However, fluorosis prevalence in the aesthetically important maxillary central incisors measured blind to year and fluoridation status from oral photographs was reduced following downward adjustment of water fluoride concentration. Based on the cross-sectional comparison of children with Full-CWF and No-CWF in 2016-17, the lower concentration of 0.6 to 0.8 ppm fluoride is an effective caries-preventive measure. However, the before and after study indicated that downward adjustment of water fluoride concentration may have reduced the caries-preventive effect of CWF in primary teeth. Further research is needed to evaluate the impact of the downward adjustment on dental caries in permanent teeth of children and adults with CWF.
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    Determining competence in prosthodontics in undergraduate dental school programmes: an international study
    (University College Cork, 2022-12-09) Al Khalaf, Khaleel; Lynch, Christopher D.; Da Mata, Cristiane
    Background and aims: In an era of increased attention on patient safety, as well as increased student mobility between many countries, it is of interest to investigate contemporary international trends in the teaching and assessment of prosthodontics. The aims of this PhD project were to investigate the teaching and assessment methods of the prosthodontics domains and to determine if it is possible to agree on competency standards in prosthodontics. Structure and methods: This thesis includes an introductory chapter (Chapter 1), a narrative review of relevant educational and prosthodontic literature (Chapter 2), four original quantitative (questionnaire-base) studies to assess the contemporary teaching and assessment methods of prosthodontics on international basis (Chapters 3-6), and a mixed-method Delphi approach among prosthodontic/restorative dentistry experts to obtain a consensus on the most suitable undergraduate teaching and assessment methods (Chapter 7). Chapter 8 includes a qualitative study using one-to-one interview to explore the perspectives and opinions of senior dental academics that did not reach consensus using the Delphi method. Chapter 9 contains a systematic review synthesising the response rates in dental literature of questionnaire-base studies. Finally, a brief conclusion of the thesis was presented (Chapter 10). Results: Narrative review: there was significant divergence among prosthodontic curricula in dental schools in terms of teaching methods, assessment criteria and how student competence is determined. Quantitative studies: Our findings from the quantitative studies reinforced the findings of the narrative review; there was a significant international divergence of undergraduate teaching and assessment trends among dental schools, including the preclinical and clinical course, of the prosthodontics divisions (complete denture, removable partial denture, fixed prosthodontics and dental implants). Divergence was evident in dental schools even within the same country. Mixed-method Delphi and qualitative studies: A total of 23 senior academic experts from 11 countries participated in the Delphi study. There was a high level (92.6%, 175 statements out of 189) of consensus agreement over three iterative rounds, whereas 14 statements (7.4%) did not achieve a consensus. A total of 12 senior dental academics from seven countries participated in semi-structured interviews, it was agreed that academic professors, consultants, or specialists were the most suitable staff members to supervise students during preclinical hands-on sessions in removable and fixed prosthodontics. In addition, participants mentioned the availability of suitable patients for treatment, dental schools’ curriculum and the level of students’ skills as factors influencing the starting point of clinical sessions in fixed prosthodontics. We also found differences among the participating schools in regard to course contents and extent of teaching on dental implants. The experts suggested tailoring the curriculum according to what is expected from the graduating dentists and allowing students to observe dental implant cases before treating simple cases. Systematic review of response rate: Overall, 133 studies with 149 response rates were included. The median response rate across the included studies was 77%, a significant negative correlation was observed between the response rate and the actual number of distributed questionnaires (sample size) (r = -0.4127; P<0.001). there was an association between the response rate and the area of distribution (e.g., national or international, P= 0.0012). Yet, it was unclear whether if there are correlations between the response rate and other variables (e.g., piloting, number of questions and the journal impact factor). Conclusions: This thesis highlighted the current divergence in teaching and assessment methods of undergraduate prosthodontics. However, this divergence can be minimized, and the international harmonization of the dental curricula is highly possible by reassessing and tailoring the dental curricula. We presented a list of senior academics’ consensus statements on the teaching and assessment methods of prosthodontics. In addition, multiple recommendations and challenge resolutions were suggested and introduced. Thus, our findings can be considered as guidelines and references to develop recommendations for stakeholders involved in undergraduate curricula among dental schools worldwide and in consistence with the local dental council recommendations, which will ensure dentists with the same level of competence at graduation.
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    Comparison of statural height growth velocity with chronological age and dental development at different cervical vertebral maturation stages in a contemporary Irish population
    (University College Cork, 2021-07) Coffey, Diarmuid John; Millett, Declan
    Aim: The aim of this study was to investigate if a correlation exists between CVM stage and statural height growth velocity, chronological age and dental development in a contemporary Irish population. Materials and Methods: Following ethical approval, a total of 269 subjects were recruited from the orthodontic treatment waiting list at Cork University Dental School and Hospital (CUDSH). All participants had a digital lateral cephalogram and DPT as part of their initial orthodontic records. Standardised standing height was also measured at this initial appointment and at subsequent 6 to 8 week intervals for approximately one year to calculate a mean annualised growth velocity (MAGV). A single calibrated observer assessed CVM stage from lateral cephalograms using the method described by Baccetti et al., (2005) and dental development stage of the mandibular second permanent molar from each DPT using Demirjian’s Index. Chronological age was determined from the subject’s chart. Statistical analysis of MAGV, chronological age and stage of dental development were performed using ANOVA, with CVM and gender as factors. Pairwise comparisons were made between CVM stages. Results: The final sample comprised of 218 subjects (121 females, 97 males), with a mean age of 14.02 (SD 1.97) years and age range of 8.82-18.77 years. Intra-observer (ĸ = 0.97) and inter-observer (ĸ = 0.94) reliability of CVM stage assessment were ‘almost perfect’. Intra-observer reliability for dental development stage was also ‘almost perfect’ (ĸ = 0.97). There was a statistically significant difference in MAGV between CVM stages (p<0.0001) and between genders (p<0.0001). The peak in statural height growth velocity occurred at CVM stage 3 in both males (mean age 13.39 (SD 0.75) years) and females (mean age 11.95 (SD 0.82) years). Chronological age exhibited significant differences between CVM stages (p<0.0001) and between genders (p<0.0001). There was also a statistically significant difference in the distribution of dental development stage between CVM stages (p<0.0001) and between genders (p=0.0292). Conclusions: • MAGV differed significantly between successive CVM stages in both males and females, with the peak in statural height growth velocity found at CVM stage 3. • Chronological age differed significantly between CVM stages, and these differences were dependent on gender. • The distribution of dental development stages differed significantly between CVM stages and between genders.
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    To investigate the effect of plasma rich in growth factors (PRGF) on healing and quality of life following mandibular third molar removal
    (University College Cork, 2021) O'Sullivan, Laura; Ni Riordain, Richeal
    Objectives: To investigate the effect of plasma rich in growth factors (PRGF) on clinician-reported and patient-reported outcomes following surgical removal of a unilateral impacted mandibular third molar. Materials and Methods: Ethical approval to conduct this prospective, double-blind randomised controlled trial (RCT) was granted by the local Clinical Research Ethics Committee. Seventy-four patients requiring surgical removal of a single impacted mandibular third molar (M3M) under local anaesthesia were recruited to participate. A blood sample was obtained immediately pre-operatively (T0) for all participants irrespective of study arm allocation, and PRGF prepared according to the product protocol. Patients allocated to the treatment arm received PRGF clot in the third molar socket after tooth removal. All patients received a telephone call 3 days postoperatively (T1), and were asked to return to the clinic for review 7 days postoperatively (T2). Primary outcome measures were NRS (numeric rating scale) pain score, OHIP-14 (Oral Health Impact Profile-14) and PoSSe (Postoperative Symptom Severity) scale data. Secondary outcome measures such as mouth opening (MIO), dry socket, socket healing and analgesia consumption were also explored. Statistical analysis was performed using IBM SPSS® 25.0 software and Stata® 15.1. ANCOVA was used for analysis of NRS, OHIP-14 and PoSSe total scores and MIO outcomes. Categorical variables were analysed using the Chi square test. Results: The mean age of participants was 28.1years (range 19-39, SD 5.8) with females accounting for 77% of the study population. NRS scores were higher in the PRGF group at T1 (4.1±2.4) demonstrating borderline significance (p=0.06) with no significant difference at T2. No significant differences were observed in PoSSe subscales between groups overall, with the exception of the ‘interference with daily activities’ subscale at T1, with PRGF patients scoring on average 1.2units higher (p=0.02). OHIP-14 outcomes revealed patients in the PRGF group were 25% more likely to experience discomfort on eating at T1 (p=0.02) with no significant difference between groups at T2. Reduced MIO was observed at T2 in control (35.7±8.2) and PRGF groups (35.4±8.5), but was not significant (p=0.67). The incidence of dry socket was not significant between groups (p=0.3). Socket healing, graded using a modified Landry et al healing index, did not vary significantly between groups: control 4.0±1.2, PRGF 3.6±1.2, nor did analgesia consumption. Conclusion: The results of this study did not demonstrate any significant difference in clinical or quality of life outcomes in patients following adjunctive use of PRGF in mandibular third molar sockets.
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    Children and adolescents and modified twin block for Class II division 1 malocclusion compared to controls: quantitative and qualitative analyses
    (University College Cork, 2021-07) O'Dwyer, Caroline; Millett, Declan
    Aims • To evaluate the impact Modified Twin Block (MTB) treatment has on oral health related quality of life (OHRQoL), self-esteem, self-perception of aesthetic treatment need and 3D soft tissue facial changes in children with Class II division 1 malocclusion (II/1M) compared to children with II/1M awaiting treatment who served as controls. • To assess the effect MTB treatment has on family quality of life (QoL) and on both the parent’s perception of their child’s OHRQoL and aesthetic treatment need compared to controls. • To assess the level of agreement of child OHRQoL and perception of aesthetic treatment need by child and parent between groups. Materials and methods Following ethical approval, 60 subjects (31 males; 29 females) received MTB treatment (MTB group) and 47 subjects (22 males; 25 females) with II/1M awaiting treatment served as controls (Control group). At baseline (T1) and following MTB treatment/recall (T2) all subjects completed the Child Perception Questionnaire (CPQ11-14), Child Health Questionnaire short from (CHQ-CF45) and self-assessed aesthetic treatment need (IOTN-AC). Each child also had a 3D facial image captured at rest. At the same time points, a parent of each child completed the Parent-Caregiver Perception Questionnaire (P-CPQ) and assessed their child’s aesthetic treatment need (IOTN-AC). Comparisons of patient demographics were made using ANOVA and Chi-square tests. ANOVA was used for comparisons in CPQ, P-CPQ, CHQ-CF45 and 3D soft tissue facial changes at T1 and T2 between groups and paired t-tests were used within both groups. Bowker’s symmetry test was used to compare IOTN-AC within groups and Fisher’s Exact test was used between groups. ANOVA was used to test for associations between CPQ, CHQ, IOTN-AC, and 3D soft tissue facial change. Results Forty-two subjects (20 males; 22 females) completed MTB treatment (average duration 8.5 months; range 5-12 months) and 35 untreated II/1M subjects (15 males; 20 females) were recalled after an average time of 11 months (range 9-13 months). At T1, groups were similar in age (p=0.1402) and gender (p=0.2973) but overjet in the MTB group was slightly greater (p=0.0016). At T2, there was a significant improvement in the MTB group in overall OHRQoL (p<0.0001) and self-perception of aesthetic treatment need (p=0.018) but there was no change in self-esteem (p=0.144). Significant improvements occurred in family QoL (p=0.0001), in parent’s perception of both their child’s OHRQoL (p<0.0001) and aesthetic treatment need (p<0.0001). In the MTB and Control groups and at both time points, the level of agreement between child and parent perception of the child’s OHRQoL was poor with parents rating it worse [MTB group T1, p=0.0001; T2, p=0.003]; [Control group T1, p=0.001; T2, p=0.008]. At T1, parents rated the aesthetic treatment need to be greater than their child in the MTB group (p=0.054) and Control group (p=0.04). At T2, the level of agreement between the child and parent in their aesthetic treatment need was similar (p=0.262) but in the MTB group children perceived their aesthetic treatment need to be greater than their parents (p=0.019). From T1 to T2, significant 3D soft tissue changes occurred at Pogonion in the MTB group 4.26 mm (p= 0.001) and in the Control group 3.29 mm (p=0.002) but the mean difference between the groups (0.97 mm; p=0.011) was not clinically significant. Conclusions • MTB treatment significantly improved the OHRQoL and self-perception of aesthetic treatment need in children with II/1M but had no significant impact on self-esteem or 3D soft tissue facial changes compared to controls. • MTB treatment significantly improved the family QoL and both the parent’s perception of their child’s OHRQoL and aesthetic treatment need compared to controls. • In children following MTB treatment or awaiting treatment, poor agreement existed between the child and parent perception of OHRQoL and aesthetic treatment need.