DSpace Collection:
http://theses.ncl.ac.uk/jspui/handle/10443/92
2024-03-29T10:33:04ZDental ExtraCtion versus filling of adult teeth In chilDren: an Economic evaluation (DECIDE)
http://theses.ncl.ac.uk/jspui/handle/10443/5983
Title: Dental ExtraCtion versus filling of adult teeth In chilDren: an Economic evaluation (DECIDE)
Authors: Taylor, Greig Daniel
Abstract: Introduction
This thesis identifies the most efficient pathway for children with compromised first permanent
molar (cFPM) adult teeth, comparing extraction versus restoration, including establishing and
incorporating public willingness to pay (WTP). Adolescents’ and adults’ views and experiences of
managing cFPM were qualitatively established. cFPM, most commonly due to dental caries and
molar-incisor hypomineralisation, cause pain and impact children across England. Clear guidance on
whether to restore or extract cFPM in children does not exist.
Methods
This thesis comprises three complementary studies. Online semi-structured interviews were
undertaken with adolescents and adults. Transcripts were thematically analysed. A discrete choice
experiment was designed and disseminated to 430 members of the public. Conditional (fixed
effects) logistic regression established public preferences, and WTP. An individual patient-level
microsimulation model was built, and parameterised, to compare the relative efficiency of initial
cFPM strategies over the life course of a child.
Results
Several internal and external factors influence adolescents’ and adults’ management of cFPM. Any
decision should be made in a shared-care approach, ensuring active involvement of adolescents.
There is no clear public preference to restore or extract cFPM in a child, providing the resultant
space was closed spontaneously or orthodontically. A preference exists for management by a
general dental practitioner or a specialist. The public prefer decisions to be made by a parent, or in
conjunction with the dentist. Base-case analysis, and scenario analyses, suggests the most efficient
approach is to extract cFPM between the age of seven and ten. Definitively restoring is an efficient
option but is less so than extraction. In the scenario modelled, active monitoring and temporary
filling, followed by extraction at the optimum time, are dominated strategies and should not be
offered.
Discussion
Clinical and policy implications of these findings, limitations of the methods used and
recommendations for future research are discussed.
Description: Ph. D. Thesis2023-01-01T00:00:00ZAn exploration of the life course determinants of oral health in the United Kingdom
http://theses.ncl.ac.uk/jspui/handle/10443/5348
Title: An exploration of the life course determinants of oral health in the United Kingdom
Authors: O’Connor, Rhiannon
Abstract: Poor oral health has a substantial impact at both an individual and societal level and
develops across the life course. This research explored the life course determinants of oral
health in the UK, addressing an existing lack of research in this field.
This mixed-methods research utilised an existing longitudinal prospective birth cohort study
– the Newcastle Thousand Families Study – which recruited 1,142 babies born in Newcastle
upon Tyne in 1947. Twenty in-depth interviews were conducted with participants at age 67,
to explore what influenced how they looked after their oral health across the life course.
The broader life course determinants of age 63 tooth retention in this cohort were
subsequently modelled using path analysis techniques.
The interviews revealed that a range of factors influenced oral health behaviours, centring
around four sources: the dental profession, wider society (e.g. schools, peers, the media),
family members and the individuals themselves. Determinants varied to some extent
between different behaviours and also across the life course. Parents were reportedly the
predominant influencers in childhood, whilst individual-level and peer influences played a
major role during the transition to independent adulthood. Throughout independent
adulthood, influences were diverse, although, notably, family influences transferred from
parents to spouses and children, especially the former.
The path analysis demonstrated that multiple factors across the life course influenced age 63
tooth retention, including smoking and dental attendance, socio-economic determinants,
dental anxiety, sex and parental encouragement. However, the potential influence of
unmeasured factors (specifically sugar consumption) could not be established due to data
limitations.
Subject to potential differences between this 1947 cohort and contemporary generations,
this research suggests that oral health interventions should target an array of behavioural,
social and psychological factors at the level of individuals, families, society and the dental
profession, prioritising the most appropriate determinants at each life course stage.
Description: Ph. D. Thesis.2021-01-01T00:00:00ZThe pH and Concentration of Hydrogen Peroxide – Impact upon Dental Enamel Properties and Response to Dietary Staining, Erosion, and Remineralisation
http://theses.ncl.ac.uk/jspui/handle/10443/5324
Title: The pH and Concentration of Hydrogen Peroxide – Impact upon Dental Enamel Properties and Response to Dietary Staining, Erosion, and Remineralisation
Authors: AlKahtani, Rawan Nasser S.
Abstract: Hydrogen peroxide (HP) based whitening products can damage enamel due to their pH and
concentration. This in-vitro study investigates the effect of HP pH and concentration on selected
enamel properties. In addition, combined effects of whitening/remineralisation and subsequent
resistance to simulated dietary erosion and staining were investigated.
Polished bovine enamel samples were treated with 6, 20, 40wt.% HP at pH 5, 7 and 9, for 2
hours daily for ten days. Samples were stored in artificial saliva at 37C before and after
treatment. Whitening/remineralisation investigations were performed using 6wt.% HP in
combination with either casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) or
nanohydroxyapatite (nHA). Samples were then subjected to simulated dietary staining using
coffee and erosion using 0.3% citric acid (pH3.8). Measurements of enamel roughness (Ra),
hardness (HV), and colour change (E) were made before and after treatment using atomic
force microscopy, micro-hardness testing, and spectrophotometry. Mineral loss and qualitative
surface evaluations were undertaken using energy dispersive x-ray spectroscopy (EDX) and
scanning electron microscopy (SEM), respectively, after treatment.
As HP concentration increased and pH decreased there was a statistically significant increase
in E (P<0.05). Greatest increase in Ra and decrease in HV occurred in enamel treated with
pH9 40% HP. Remineralisation did not significantly affect E, Ra, and HV of whitened enamel.
CPP-ACP was effective in preventing statistically significant changes in Ra and HV values
after erosive cycling. Enamel treated with nHA exhibited the greatest dietary stain uptake. No
significant changes in enamel Ca, C, and P occurred after whitening, remineralisation, and
erosion. SEM images revealed distinct surface changes mostly in pH9 and nHA treated samples.
All whitened specimens exhibited significantly greater colour change than the control group.
Neutral HP caused the least damage to whitened enamel while producing a satisfactory
whitening effect. Remineralising agents did not reduce whitening side effects, however, CPPACP prevented significant Ra and HV changes after dietary erosion.
Description: Ph. D. Thesis.2020-01-01T00:00:00ZThe influence of sirtuin-controlled circadian rhythmicity anddiet on lifespan in the honey bee, Apis mellifera
http://theses.ncl.ac.uk/jspui/handle/10443/5239
Title: The influence of sirtuin-controlled circadian rhythmicity anddiet on lifespan in the honey bee, Apis mellifera
Authors: Donley, Dion Ian
Abstract: This thesis explores the role of sirtuin controlled circadian rhythmicity and diet on honey bee
longevity. By manipulating the circadian period of newly emerged honey bees and using
qPCR to measure the expression of metabolic and circadian genes, we attempt to understand
the effect of non-24 h circadian periods on longevity. We found evidence that altering the
circadian period to 20 h or 28 h resulted in reduced longevity and a 1.6-fold increase in
mortality, disruption to circadian clockwork and observed that this effect was not additive
with that of a high-EAA diet, suggesting a potential shared pathway (Chapter 3).
Rapamycin is an inhibitor of the mTOR pathway and has been shown to extend lifespan
across species. We investigate the effect of rapamycin on longevity and appetite in the honey
bee. We also observe the effects of rapamycin in combination with high-EAA diets. We found
no evidence of any life extending effects and in some cases a reduction in longevity as well as
polyphagic behaviour common in metabolic diseases (Chapter 4).
Methylation plays an important role in sirtuin controlled mediation of lifespan, however the
study of methylation in insects is time consuming and costly due to low global methylation
levels. In this study we aim to test the viability and suitability of common methods of
measuring global and site-specific methylation changes. We determine that methylation levels
were too low to effectively measure with generic ELISA-kits in the honey bee and this also
made site specific analysis for circadian genes challenging (Chapter 5).
In the final chapter we analyse the effect of methionine on longevity and behaviour in the
honey bees. By varying the dietary methionine content and analysing key metabolic genes
FOXO and Sir2 we attempt to determine the mechanisms controlling these effects. We found
that a high methionine diet reduced lifespan, appetite and lead to upregulation of FOXO but
not Sir2 (Chapter 6).
Description: PhD Thesis2021-01-01T00:00:00Z