Melbourne Dental School - Theses
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ItemNon-smokers, Non-drinkers: Assessing surgical outcomes in a clinically distinct cohort of Oral Squamous Cell Carcinoma patients( 2019)Background Tobacco and alcohol intake are responsible for approximately 65-70% and 20-35% respectively of oral squamous cell carcinomas (SCC). Non-smoking, non-drinking (NSND) patients represent approximately 13-35% of the oral SCC population and are more likely to be young (Mean 20-35 years) or elderly (Over 70 years) females with a predilection for tongue, gingivae and lower lip sites. Although approximately 24% of head and neck cancers occur in patients over 70 years old, there are few published reports of oral SCC in elderly patients. This group appears to be characterized by a higher proportion of NSND females. Bone invasion by oral SCC necessitates jaw resection. Ideally, pre-operative imaging can be used to guide resection. The current rate of non-invaded mandible resections ranges between 20 and 100%. Even with free-flap reconstruction, segmental resection still results in cosmetic and functional deficits, donor site morbidity and significant physiological strain resulting in increased risk, prolonged recovery and need for rehabilitation. Decreased physiological reserve and multiple medical co-morbidities make complex surgery undesirable in an elderly population. Marginal resection aims to maintain bony continuity to avoid complex reconstruction. Objectives The objectives of this study were: 1. Examine differences in survival and clinical outcomes of elderly patients without traditional risk factors presenting with oral squamous cell carcinoma. 2. Determine the accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) at identifying bone invasion in oral SCC. Materials & Methods Retrospective review of 287 consecutive patients divided into 2 treatment period cohorts treated for oral SCC between the 1st Jan 2007 and 31st Dec 2012.. Patients were classified as either smoker-drinkers (SD) or non-smoking, non-drinking (NSND). Only patients with oral sub-site primaries according to ICD-10 were included. Carcinomas of the lip, tonsil, base of tongue and oro-pharyngeal sub-sites were excluded. A subset of 109 patients who underwent mandibular resection were also reviewed for bone invasion. 83 of these patients had pre-operative CT imaging studies of diagnostic quality available for review and 72 underwent MRI which were compared to histological resection specimens. Results Of the study population (N=287), 24.4% were NSND and 9.75% were NSND elderly (older than 70 years) females. Disease specific survival at 5 years was significantly reduced when NSND elderly females were compared to all other patients (p <0.001) as well as age matched controls (p = 0.006). This effect was verified independently in each cohort. Bone invasion was detected in 44 out of 109 (40.4%) resection specimens. Bone invasion was identified on CT imaging in 31 out of 83 cases (37.3%) and by MRI in 35 out of 72 cases (48.6%). The sensitivity and specificity of CT for detecting bone invasion was 69.0% and 79.6% respectively. The sensitivity and specificity of MRI for detecting bone invasion was 87.1% and 80.5% respectively. Conclusions The results of this study suggest that NSND elderly females are a distinct patient population with poorer disease specific survival outcomes and that negative imaging studies should not preclude an oncologically safe bony resection if indicated on clinical grounds.
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ItemExploring psychological correlates of toothbrushing behaviour - a systematic review of current research and a qualitative exploration of real-time influences( 2019)This thesis explores the psychological mechanisms of toothbrushing routines among younger adults. With individual attitudes and beliefs linked to toothbrushing engagement, an improved understanding of these mechanisms is expected to have benefits for preventive oral health efforts. Current limitations are that: a) there is little agreement regarding the psychological constructs that best correlate with toothbrushing, and b) there is little explanation around the dynamic, real-time influences that may influence toothbrushing on a daily basis. Two projects were designed: a systematic review of the current literature to determine the psychological constructs that best correlate with toothbrushing, and a qualitative exploration of how real-time variables may impact toothbrushing. The systematic review screened 1117 articles. Analysis of the final sample (N=13) found that variables related to attitudes (r=0.30), self-efficacy (r=0.48), and intentions (r=0.59) had significant correlations with toothbrushing behaviour. However, findings were distorted by observations that methodology was poor/average, with the use of validated measures and reporting of statistics lacking across all studies. The qualitative study consisted of in-depth interviews (N=23) that discussed toothbrushing routines, perceived attitudes and norms related to toothbrushing, and if toothbrushing routines ever changed from day-to-day. Individuals reported that routines were subject to change, with morning toothbrushing often skipped due to stress, and night-time due to exhaustion. Those who rarely neglected brushing reported being motivated by personal reasons rather than social pressures. Findings suggest the locus of motivations and ability to self-regulate during stress and/or feelings of tiredness may play a role in the experience of real-time barriers to toothbrushing. This thesis highlights the importance of exploring psychological mechanisms within the oral health field. Future research might attempt to quantify how self-regulation relates to toothbrushing engagement in terms of real-time decision making. Researchers are suggested to investigate the role of social pressures relative to more intrinsic motivations, and are advised to focus on study design, validated measures and the use of past literature. Clinicians are advised to be conscious of the role that situational barriers may have on toothbrushing behaviour, and should consider fostering intrinsic motivation within patients, rather than using fear or social norms to elicit improved toothbrushing. Limitations to the thesis and additional suggestions for research and further exploration within this field are discussed.
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ItemSurgical Management of Recurrent Temporomandibular Joint Dislocation - Systematic Literature Review and Development of a Treatment Protocol( 2019)Recurrent TMJ dislocation is a rare entity, clinically distinct from acute or chronic dislocation. It is associated with significant morbidity and deterioration to quality of life for affected patients. Recurrent temporomandibular joint (TMJ) dislocation can be challenging to treat and current understanding regarding aetiology and management of this condition is limited. The aim of this thesis was twofold. The first was to conduct a systematic review regarding the current understanding of managing recurrent TMJ dislocation. The second aim was to review the surgical management and long-term outcomes of patients with recurrent TMJ dislocation who presented to a single Hospital Department over a period of six years so as to formulate a practical treatment algorithm. A retrospective review of cases surgically managed for recurrent TMJ dislocation was undertaken with respect to patient demographics, clinical features, surgery provided, and long term follow up. A literature review was conducted using PRISMA guidelines to identify papers published between 2006 and 2016. The resultant papers were analysed. A total of 33 papers were found relevant to the study. Minimally invasive techniques described included autologous blood injection, which was associated with an overall success of 80% at 12 months. Other modalities investigated included OK-432 sclerotherapy, laser capsulorrhaphy, botulinum toxin of the lateral pterygoid muscle or modified dextrose. These publications show promising success rates. Surgical techniques described included disc plication, eminoplasty and eminectomy. These modalities had a similar success rate, although numbers were limited. For the second part of this thesis, a total of 14 patients were identified who were managed for recurrent TMJ dislocation over a 6-year period from 2010 to 2016. The cases were followed up for a minimum of 12 months and a maximum of seven years. Results showed effective long-term resolution of symptoms using a combination of eminectomy, disc plication (meniscopexy) and where clinically indicated, lateral pterygoid myotomy. This thesis found that the true incidence of recurrent TMJ dislocation is unknown and aetiology is limited to expert opinion. The current understanding of management for recurrent TMJ dislocation is limited to case series and case reports. This thesis compiles the current understanding of management of recurrent TMJ dislocation. A decision making algorithm, with a personalised, step-wise approach to treatment is presented. The retrospective review portion of the thesis has shown that a combination of eminectomy and disc plication (meniscopexy) is effective in providing long term positive outcomes in the surgical management of recurrent TMJ dislocation. Those cases of recurrent TMJ dislocation resulting from dystonia of the lateral pterygoid muscle also benefitted from additional lateral pterygoid myotomy.
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ItemExploring the oral health curriculum in Australian pharmacy schools( 2019)Introduction Poor oral health continues to be prevalent in Australia despite ongoing advancements in oral health knowledge and care. Without innovative strategies to improve the oral health of the population, the quality of life for an increasing number of Australians will be negatively affected as poor oral health extends beyond the mouth and can affect general health and well-being. Beyond the dental clinic setting, pharmacists have been recognised in the literature to have an important role in oral health care. The potential to expand the role of pharmacists as oral health advisors has also been acknowledged. While previous studies explored the knowledge and opinions of pharmacists regarding oral health, no research has been completed to explore the extent of oral health content that is currently included in Australian pharmacy schools’ curricula or on the knowledge and opinions of the pharmacy students who are about to graduate as health professionals. Aim The aim of this study was to investigate the knowledge, attitudes and perceptions towards the role of pharmacists in oral health among final year pharmacy students in Australia, and to investigate the extent of the oral health content in Australian pharmacy curricula. Methods A cross sectional study of pharmacy students across 8 Australian pharmacy courses was undertaken using an anonymous online survey. In addition, semi-structured interviews were conducted with pharmacy course coordinators or convenors to discuss the oral health content in their course curricula. Survey results were analysed using SPSS software (SPSS 25.0, Chicago Il, USA) and the findings summarised using descriptive statistics. Phone interviews were recorded, transcribed verbatim and analysed thematically. Results A total of 45 pharmacy students across the nation completed the online survey. Almost half of the students (48.9%) reported that oral health was not included in their course. Many believed that pharmacists have an important role in oral healthcare, however only 38.9% perceived that pharmacists were appropriately trained to provide oral health education. Most students (91.7%) believed that professional relationships between pharmacists and dental practitioners could be improved, and that pharmacists had the potential to be more involved with preventing oral health issues (86.1%). Three main themes emerged from the course convenor interview study: (1) That pharmacists have a role in oral healthcare, (2) That oral health is being taught in pharmacy courses, however each did so in a varied manner, (3) Lack of space in course curricula is the key barrier for further inclusion of oral health care content in pharmacy courses. Conclusion Overall, the findings of this study provide evidence that the oral health content in pharmacy curricula in Australia is inconsistent, with students indicating that they wanted more education on oral health topics. Both students and course convenors recognised that pharmacists have an important role in oral healthcare. Therefore, pharmacy courses in Australia should consider expanding the coverage of oral health content to provide graduates with the confidence and skills they need to improve the oral health of the community.
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ItemEffect of exposure of glass ionomer cements to acid environments( 2016)This research focused on evaluating the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) incorporated into a glass ionomer cement (GIC). Two conventional GIC materials were the main focus of the study, Fuji VII and Fuji VII EP (containing 3% w/w CPP-ACP), these materials were made into rectangular blocks and subjected to various acidic media (lactic, citric and hydrochloric acids), while daily observations of surface hardness, mass loss and ion release were carried out over a three day period. Acid storage solutions were specifically chosen to approximate conditions the materials would be exposed to in an oral environment; bacterial acid challenge, food acid challenge and stomach acid reflux. Later stages of the study also included topical CPP-ACFP (casein phosphopeptide-amorphous calcium fluoride phosphate) treatment of GIC surface, as well as a more detailed analysis of ion release of Fuji VII EP compared to other materials (Shofu Beautifil). Blocks of GIC material were prepared and allowed to set in an incubator (37C, 95%+ relative humidity) for 24 hours. Surface hardness was determined using micro-indentation using a microscope-aligned indenter. Acid storage media were changed every 24 hours and all solutions were kept for further analysis of ion release. Fluoride ion concentrations were measured using an ion selective electrode, phosphate ion concentrations were determined using a UV spectrophotometry assay and calcium ion concentrations were measured using atomic absorption spectroscopy (AAS). Mass loss was determined using an analytical microbalance. Later stages of the study also measured aluminium ion concentrations, which were acquired using AAS. Data from sample groups was found to follow the normal distribution, χ2 test was used to test normality. Single factor ANOVA was used to analyse the results using Bonferroni-Holm multiple comparison. Two-way ANOVA was used to determine the interaction between incorporation of CPP-ACP and exposure to different acids. Level of significance was set at α = 0.05. Over the course of three days of storage the surface hardness of both materials reduced significantly in all acid solutions as well as a control water solution. Results showed significant increases in calcium and phosphate ion release in Fuji VII EP groups compared to Fuji VII in the vast majority of acid solutions. Fluoride release remained stable for both materials with no significant differences measured between them. Further topical treatment provided additional increases in calcium and phosphate ion release for both materials. Exception to this were groups stored in citric acid, which exhibited far greater mass loss compared to other groups, very high phosphate ion release and an increase in surface hardness. Analysis of aluminium ion release to indicated that aluminium ions are possibly chelated from the GIC matrix, leading to additional release of phosphate ions and increased mass loss. Formation of a crust surface layer seems to be the cause of increased surface hardness in topically treated citric acid groups. Comparison of fluoride, phosphate and aluminium ion release between Fuji VII EP and Shofu Beautifil showed that ion release profiles are significantly and fundamentally different between the two materials, which may be due to the level of maturation (age) of the glass and structure differences between the materials.
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ItemInfluence of the addition of microencapsulated phytoncide to a denture base resin on mechanical properties and antimicrobial activity( 2017)Background: Resins such as a polymethyl methacrylate (PMMA) are the most commonly used in denture base material (DBR) because it possesses the advantage of adequate physical, mechanical, and aesthetic properties. However, research regarding the antimicrobial properties of PMMA still remains an area of interest that requires further investigation. Objectives: The aim of this project was to fabricate a denture base resin (DBR) containing phytoncide microcapsules (PTMCs) at various concentrations and investigate its influence on the mechanical properties of DBR. It also aimed to evaluate the antibacterial effects against Porphyromonas gingivalis and determine the antifungal activity of the microencapsulated phytoncide against Candida albicans. Methods: A total of 54 rectangular shaped (64 x 10 x 3.3 mm) specimens were fabricated using the heat cure polymerisation processing method for the mechanical property testing of the DBR. The samples were divided into nine groups; 0% (control), 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 4.0%, and 5.0% (dry wt/wt%) according to the incorporation percentage. The flexural strength test was conducted by using a three-point bending test in a universal testing machine. A scanning electron microscopy (SEM) investigation was performed and evaluated the fractured surface morphology of specimens. A total of 30 disc-shaped (10 mm x 3 mm) specimens were fabricated using the heat cure polymerisation processing method for the antibacterial test. The samples were divided into two groups (0% control, 2.5% dry wt/wt%) according to the incorporation percentage of phytoncide. The disc resin samples containing PTMCs were incubated at 37°C for 76 h and the inhibition of the growth of P. gingivalis W50 in a 24 well plate set-up was observed using the turbidity method with a spectrophotometer. A turbidometric antifungal test was conducted to determine if the phytoncide plant essential oils (PPEOs) in microcapsule could produce an antifungal effect against C. albicans, under a pH 5.5 acidic environment in a 96 well plate assay. Liquid yeast peptone glucose (YPG) broth and a solid agar growth medium were used for biofilm growth. The solution was incubated at 37°C for 24 h and the optical density (OD) was observed. Results: The flexural strength decreased as more PTMCs were added to DBR; 0% (97.58 ± 4.79 MPa), 0.5% (83.55 ± 2.95 MPa), 1.0% (78.62 ± 1.45 MPa), 1.5% (69.49 ± 1.84 MPa), 2.0% (77.06 ± 3.43 MPa), 2.5% (65.72 ± 1.03 MPa), 3.0% (64.78 ± 1.53 MPa), 4.0% (56.13 ± 2.10 MPa), and 5.0% (53.66 ± 2.46 MPa). DBR containing 2.5% of PTMCs was the maximum acceptable concentration (65.72 MPa) to comply with the ISO strength requirements. The one-way ANOVA was F8, 45 = 165.99; P<0.001. For the antimicrobial test, there was no antibacterial effect against P. gingivalis. However, the antifungal test showed a dose-dependent effect on C. albicans as the phytoncide percentage increased from 0.5% to 5.0%, the OD of the culture decreased from 0.908 to -0.071. At a 2.5% concentration, the phytoncide had effectively stopped C. albicans growth. Conclusion: Fabrication of DBR containing the PTMCs was successful at 2.5% level and below without affecting the mechanical properties. This could lead to an investigation of the antimicrobial effect of DBR containing the PTMCs against oral microorganisms such as P. gingivalis or C. albicans for clinical applications. Further research on a new non-toxic carrier shell material, such as a biodegradable or semi-perishable polymer, needs to be investigated.
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ItemA descriptive medical analysis of patients receiving dental implants in private practice over a 5-year period( 2016)Background The population seeking implants in private practice is a demographically and medically diverse group. A fuller understanding of the medical conditions affecting this population can optimise treatment planning and service delivery, as well as focus the informed consent process. Objectives 1. To conduct a retrospective cohort study reviewing and describing the medical and demographic data of patients seeking implants in private dental practices over a five-year period in Victoria, Australia. 2. To create an evidence based clinical picture of the medical background of the typical patient seeking dental implants in the private practice setting. Material and Methods Privately practicing dental clinicians were invited to participate in the study. Data were collected pertaining to 4,116 patients who met the inclusion criterion of at least one implant placed or restored within the study period of 1st of January 2005 to 31st of December 2009. Information was collected regarding: clinician demographics; patient demographics, co-morbidities and oral status; surgical procedure; implant details; restoration details; and any complication details. Descriptive statistics and frequency analyses were conducted to describe the population with respect to patient demographics, comorbidities and medication usage. Results Demographic data relating to age and gender were obtained. Common comorbidities, their prevalence and associated medications were defined where possible. The most common age group to receive implant therapy was between 51 and 60 years (30.4% of patients). A broad range of co-morbidities was reported, including psychiatric disorders, cardiovascular disorders and diabetes. Smoking tobacco was more prevalent amongst the study population than any prescribed pharmaceutical agent. Conclusion Over 70% of all implant patients in this study were aged between 41 and 70 years of age. This period of life is associated with a diverse group of medical conditions and pharmacological therapies that often increase in prevalence with age. Clinicians must be familiar with their target demographic, understand the common comorbidities amongst this patient group and be conscious of how their presence can influence clinical decision making and outcomes. This facilitates treatment planning founded on individualised risk / benefit stratification and informed consent, and a surgical plan that is executed in the setting of patient specific peri-operative optimisation and follow up.
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ItemA retrospective analysis of grafting and adjunctive procedures performed to facilitate dental implant therapy in private practice( 2016)Purpose: To retrospectively describe and analyse, with reference to the published literature, the augmentation profiles and any associated complications of grafting for dental implants that were placed and/or restored in private practice in the state of Victoria, Australia. Materials and Methods: Specialist and general dentists, and oral and maxillofacial surgeons who were placing and/or restoring implants during the period January 2005 to December 2009 were invited to participate in the study. Data were extracted by trained and calibrated research assistants from anonymised patient histories. Information was collected on augmentation techniques of onlay and particulate grafting, open and closed sinus lifting, socket preservation and soft tissue procedures. Complications were categorised as surgical (technical): neuro-sensory disturbance, pain, bleeding, swelling, bone perforation, insufficient bone quantity or quality or inadequate primary stability; and biological: Infection, bone loss, failure to osseointegrate, loss of integration, and peri-implantitis. Cross tabulation was carried out in IBM SPSSTM to provide statistics on frequency, timing of procedures, materials and complications. Uni- and multi-variate analysis was performed to assess independent risk factors of augmentation complications using GenStat®. Complications at implants sites that were augmented were compared to the sites that were not augmented. Results: During the period January 2005 to December 2009, 8486 implants were placed in 4116 patients. Nearly one third (26.9%) underwent at least one augmentation procedure either before or at the same time as placement. Particulate grafting was the most common hard-tissue procedure (21.4% of implants) and 63.1% of these were simultaneous, single-stage implants. In 35.9% of grafts, barrier membranes were used. 5.5% of implants had a soft tissue procedure recorded. The most popular materials overall were Bio-Oss® (Geistlich Biomaterials: Pharma North America Inc.) and autogenous bone. 92.9% of onlay grafts and 83.7% of open sinus lifts had a healing period before implant placement (mean overall healing period 6.7 months). The anterior maxilla was the most common site for all augmentation procedures. There was a significant difference in the overall complication rate between the augmented implant sites and the sites that were not augmented (17.3% versus 12.6%; p=<0.001). The hard tissue augmented group had significantly more cases of insufficient bone and/or more dehiscences (2.10% v 0.58%; p<0.001) and bone loss (0.61% v 0.19%; p=0.0014) at implant placement than the non-augmented group. In these cases, implants were placed and grafted simultaneously (p<0.05) with particulate autogenous bone and/or Bio-Oss (p<0.05) in combination with resorbable xenograft membrane (p<0.001). There was significantly more bone loss in open sinus lifted cases than in cases where implants were placed in native bone (1.90% v 0.30%; p=-0.009). Other factors such as augmentation technique or material used, healing period length or timing of implant placement, were not found to significantly contribute to the complications, on multi-variate analysis. Conclusions: Augmentation procedures were required for nearly one third of implants placed, highlighting their importance in routine dental implant treatment and potential for complications to influence implant outcomes. The study demonstrated no relationship between graft complication and any specific augmentation technique or material. This suggested that routine grafting procedures used in private practice were safe and appropriate despite a recent drive to avoid augmentation by using angulated, narrow or wide implants, in addition to zygomatic implants, as alternatives, when native bone might be lacking. A small (5%) but statistically significant increase in complication rate in the augmentation group did not preclude implant placement or aberrantly affect implant outcome in the short-term. Whilst there are no guidelines with respect to the best materials to use for augmentation, the use of membrane, healing periods, and timing of procedures, this study demonstrated practices and complication rates largely in keeping with the published literature.
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ItemSquamous cell carcinoma involving the maxilla: a 20 year retrospective review( 2015)Background: Squamous cell carcinoma (SCC) may primarily involve the maxilla via tumours of maxillary sinus origin or via tumours arising from the hard palate or maxillary alveolus within the oral cavity. Both of these presentations represent a small subset of head and neck squamous cell carcinoma making SCC involving the maxilla a relatively uncommon disease. Aims: To examine our institution’s experience with SCC involving the maxilla and to compare the outcomes of patients with SCC involving the maxilla via the oral cavity with patients presenting with maxillary sinus SCC. In addition to this we evaluated our experiences regarding cervical metastases in patients with being treated for maxillary sinus SCC. Materials and methods: A retrospective review of patients with SCC involving the maxilla treated with curative intent via the Head and Neck Oncology stream at the Royal Melbourne Hospital between 1990 and 2010 was undertaken. Data collected was analysed to determine the influence of primary site on patient outcomes. Data was also examined to determine the incidence of cervical metastases at presentation and subsequent regional failure in patients with maxillary sinus SCC. Results: Influence of site of origin on the outcome of squamous cell carcinoma involving the maxilla – oral versus sinus. When compared with tumours involving the maxilla via the oral cavity, maxillary sinus origin did not per se confer a poorer prognosis. Maxillary sinus tumours were however more likely to present with advanced T-stage (T3/T4) and were more likely to have positive margins after resection. Cervical metastases in maxillary sinus squamous cell carcinoma The incidence of clinically or radiographically detected cervical metastases in our patients was 11%. At our institution, the majority of patients treated for maxillary sinus SCC underwent elective neck irradiation, with an overall regional failure rate of 4%. Our results found that local recurrence rather than regional metastasis was the primary source of treatment failure Conclusions: Influence of site of origin on the outcome of squamous cell carcinoma involving the maxilla – oral versus sinus. Site of origin does not in of itself confer a poorer prognosis; rather maxillary sinus SCC is more likely to remain occult until locally advanced and given the complex anatomy of the midface obtaining adequate margins during surgical resection is more difficult. It is these factors rather than the site of origin that affect prognosis. Cervical metastases in maxillary sinus squamous cell carcinoma: Despite typically presenting with advanced T-stage, clinical or radiographic nodal involvement at the time of presentation was uncommon in patients with maxillary sinus SCC. In our study post treatment failure more commonly occurred at the primary site than as a result of regional metastases.
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ItemInfluences on the dentine seal in direct adhesive restorations( 2014)The purpose of this research was to investigate the factors involved in the sealing ability of direct adhesive restorative materials to tooth structure, in particular dentine. Adhesive restorative materials include resin composite (RC), glass-ionomer cement (GIC) and resin-modified glass-ionomer cement (RMGIC). GICs and RMGICs have been advocated for use as a dentine replacement material. The inclusion of GICs and RMGICs within the dental armamentarium has led to sandwich or laminate restorations, which are a combination of GIC/RMGIC and RC. Other restorative techniques also include the use of a flowable RC (FRC) for lining a tooth cavity, as well as bulk-filling RCs. The type of resin adhesive agent can also influence the dentine seal. In order to establish a structured knowledge framework of adhesive restorations, a systematic review was undertaken to evaluate the current evidence of the clinical outcomes of GIC-based laminate RC restorations and FRC-lined restorations compared with non-laminate RC restorations. Subsequent analysis of the limited number of appropriately designed clinical studies showed no significant differences in clinical outcomes for RC restorations either with a flowable RC liner or GIC-based liner compared with RC restorations with no liner. However, the majority of the reported clinical studies measured outcomes within a short time frame of up to 24 months. More long-term split mouth randomised controlled clinical trials are needed, particularly with respect to comparing both open and closed-laminate RC restorations with non-laminate RC restorations. The review established that there was a need to strengthen the evidence on the biomechanical aspects of RC restorations lined with GIC materials and FRC that may influence restoration outcomes. A laboratory study on the changes of fluid flow in dentine was undertaken to quantitatively examine the sealing ability of various types of adhesive restorations. Comparisons were made using conventional nano-hybrid RC, Herculite® Ultra. The restorative techniques investigated included closed-laminate restorations with a high viscosity GIC, Riva SC HV, and a high viscosity RMGIC, Riva LC HV, a nano-hybrid bulk-fill RC, SonicFill™, a two-step self-etch adhesive agent, Optibond™ XTR, an all-in-one adhesive agent, Scotchbond™ Universal Adhesive. Mesio-occluso-distal cavities were prepared and restored on 42 extracted human teeth. For each type of restoration, the fluid flow through the dentine was recorded at different stages of the restorative procedures and at particular periods after completion of each restoration. Statistical analysis used one-way analysis of variance (ANOVA), and Fisher’s LSD test; repeated measures using one-way ANOVA were used to compare effects of the restorative procedures on fluid flow over time. All analyses were carried out at the 0.05 level of significance. Initially, placement of either a GIC or RMGIC base significantly reduced dentine permeability. However over time, the changes in dentine fluid flow after four months of storage were similar among all types of restorations (p > 0.05). The lowest reduction in fluid flow after immediate dentine bonding was associated with the two-step self-etch adhesive, Optibond™ XTR. Shrinkage from RC polymerisation can affect the durability of the seal between restoration and tooth. It was therefore appropriate to measure the effects of this shrinkage on the remaining tooth structure after cavity preparation. A subsequent laboratory study investigated the effects of polymerisation by comparing differences in cuspal movement between teeth restored with SonicFill™, Herculite® Ultra, and Herculite® Ultra with a RMGIC base, Riva LC HV, or a flowable RC, Premise™ Flowable. Mesio-occluso-distal slot cavities were prepared on 24 extracted human teeth which were randomly assigned into groups and restored. The degree of linear cuspal movement was measured with direct current differential transformers during the restoration phase and immediately after completion of the restoration. Statistical analyses used one-way analysis of variance (ANOVA), and multiple comparisons were carried out using Fisher’s LSD test at the 0.05 level of significance. The results found no statistically significant differences in overall cuspal movement among the types of restorations. The data indicated that placing a RMGIC or a flowable RC lining did not significantly reduce cuspal movement, compared with conventional nano-hybrid RC restorations with no lining. In addition, there was less variability in cuspal movement in teeth restored with bulk-fill RC. Based on the laboratory investigations, laminate restorations display sealing ability that is just as effective as incrementally placed RC restorations with no lining, as well as bulk-fill RC. There appears to be no significant clinical benefit in the placement of laminate restorations compared with RC restorations with and without FRC liner. The conclusions from both laboratory investigations support the findings of the systematic review. In addition, the sonic-activated bulk-filled RC displayed similar degrees of cuspal movement compared with conventional RC.