College of Dentistry - B.Sc. (Dent) Projects

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Browsing College of Dentistry - B.Sc. (Dent) Projects by Title

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    A 30-year retrospective study of single-unit and splinted implant supported crowns and their effects upon adjacent tissues and teeth in a Canadian Dental School Environment
    (2022-07-07) Sarzynski, Isabella
    Objective: A retrospective study at a Canadian dental school evaluated the survivability of single-unit and splinted implant supported crowns and their effects on adjacent tissues. Methods: Data from patients of all ages was collected from the institution’s computer patient management software (AxiUm) and physical charts. Results: A total of 678 implant supported crowns (586 single-unit and 92 splinted) were placed at the University of Manitoba Dr. Gerald Niznick College of Dentistry between September 10, 1989 to January 1, 2020. Of the implant cases, 249 (36.7%) of them were smokers, 64 (9.44%) were diabetic and 96 (14.2%) were reported to experience bruxism. Within the duration of the study, 17 (2.90%) single-unit crowns and 5 (5.43%) splinted crowns failed and warranted a replacement. Furthermore, 371 single-unit (63.3%) and 46 splinted (50.0%) implant crowns were a complete success as they had no complications with the crown itself or adjacent tissues. Therefore, 215 single-unit (36.7%) and 46 splinted (50.0%) crowns endured some type of complication with the crown or adjacent tissues which may have led to its failure. Overall, 96.8% of cases experienced no failure as of the study end date and a log rank test was performed to determine if there were differences in the survival distribution for the single-unit and splinted implant supported crowns (χ2(2) = 1.285, p = 0.257). Conclusion: The survival distribution of single-unit and splinted implant supported crowns was not statistically significant as they both presented with high success rates and minimal complications. Although some limitations and challenges were present, this study highlights the longevity and complications of implant supported crowns in order to improve their functionality and lifespan as well as to maintain the health of adjacent teeth.
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    AN ANALYSIS OF PURE ORBITAL BLOWOUT FRACTURES: Demographics and surgical outcomes
    (2017) Diamond, Justin; Elgazzar, R.; Shah, A.
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    Assessment of Discectomy and Eminectomy for Temporomandibular Joint Derangement: Manitoba Experience
    (2019-10-10) Manghera, Harmeet; Elgazzar, Reda; Shah, Adnan
    Temporomandibular joint disorder (TMD) is caused by the loss of function of the intra-articular tissues, leading to a failure in the biomechanics of the joint. Non-surgical modalities and less invasive surgical procedures such as arthroscopy are usually employed to manage patients with TMD in their earlier stages of the disease. Many patients respond well to such modalities while others fail to show satisfactory improvement. Hence, they qualify to be treated with more invasive open joint surgery such as arthroplasty. The aim of this study was to assess the surgical outcomes of temporomandibular joint (TMJ) arthroplasty, discectomy and eminectomy for the management of the refractory TMD cases. The retrospective chart review was conducted on TMD patients who were diagnosed and treated with arthroplasty, eminectomy and discectomy at the Health Sciences Centre (HSC) and the Seven Oaks General Hospital (SOGH) between the years of 2011 and 2017. The University of Manitoba Research Ethics Board (REB) provided approval for the project. A data capture sheet was created for data collection. Pre-operative, intra-operative and post-operative information was recorded. Eight (22%) males and 28 (78%) females incorporated the study group with ages ranging from 17 to 68 years with a mean of 40.4 years. The follow up period ranged from 1 to 29 months with a mean of 8.6 months. All patients had adequate recovery after receiving the arthroplasty supplemented with post-operative physiotherapy. Majority of these patients showed a noticeable increase in the range of jaw motion and a reduction in pain. No major complications were reported, a few minor complications were observed including numbness of the ear, transient weakness of the surrounding muscles due to impingement or stretching of the facial nerve and minor scar formation on the skin. The results show that TMJ arthroplasty is an effective and definitive surgery for the treatment of refractory TMD.
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    A Case Series Study on Pulp Calcification Following Orthodontic Treatment of Ectopic Maxillary Canine Teeth
    (2016) Rodillo, Michael
    Introduction: Impaction of maxillary canines is an identifiable anomaly that is encountered in orthodontics. Extrusive orthodontic forces on ectopic teeth may have a correlation with the cause of altered pulpal conditions such as pulpal necrosis, pulp obliteration, and pulp calcifications. Objective: The aim of this study was to describe the pulp status and recognize the incidence of pulp calcification on a series of orthodontically treated, ectopic maxillary canine cases. Materials and Methods: Sixteen patients that had undergone orthodontic extrusion of their maxillary canines were evaluated. These patients had either unilateral or bilateral ectopic maxillary canines at or above the CEJ of adjacent teeth. A total of 22 canines were examined clinically and radiographically. Results: From the sample of 22 maxillary canines which had undergone orthodontic extrusion, 7 canines (31.8%) displayed evidence of having non-vital pulps and 4 of the canines (18.2%) were determined to show an asymptomatic pulpal response due to pulp calcification. Conclusion: Essential information correlating the effects of maxillary extrusion to pulpal calcification may be utilized with further studies to determine definitive correlations of any cause-and-effect relationship that may exist.
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    Dentin Preservation in the pericervical area after preflaring with Gates-Glidden or X-Gates drills. An ex vivo micro CT study
    (2016) Wong, Bryan
    Introduction: This study compared the dentin preservation in the distal wall of mesial canals in mandibular molars after preflaring with X-Gates (XG, Dentsply Tulsa Specialities, Tulsa, OK) or Gates-Glidden (GG) drills (Dentsply Tulsa Specialites). Methods: Sixty mesial canals of mandibular molars were evenly allocated into two balanced groups for preflaring procedures: group XG – canals were preflared with a single XG drill or group GG - Drill series (n.1, 2, 3 and 4). With the aid of a micro-computed tomography scanner, dentin removal towards the furcation was measured at 3 levels: furcation (0 mm), 1mm, and 2mm apically. A paired t-test was performed to assess differences before and after procedures in the same group and one-way ANOVA was performed to assess differences between the groups. Results: Significant decrease in dentin thickness was found in the distal area of mesial roots after preflaring procedures in both groups (P < .0001). No significant difference (P > .05) was observed between XG and GG with regard to dentin preservation. Regarding the level where preflaring was done, significant difference (P < .05) was only detected in the mean values of dentin thickness between 0 mm (411.6 um) and 2mm (251.4 um) in the XG group. Conclusion: Both XG and GG groups resulted in significant decrease in dentin thickness but no difference was observed between the XG drill group and GG drill group in dentin removal towards the “danger zone”.
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    Determinants of Dental Caries in Infants
    (2016) Christensen, Jodie
    Objectives: The origins of early childhood caries (ECC) begin prenatally, before teeth arrive. Maternal vitamin D status during pregnancy may affect calcification of the developing dentition, and subsequently predispose children to developmental defects of enamel ECC. This study was conducted in order to determine whether a relationship exists between prenatal maternal vitamin D status (via a cord blood sample) and caries prevalence in offspring. Factors predisposing children to ECC were also explored. Methods: A prospective cohort of expectant mothers was selected from a high-risk urban population seeking prenatal care in Winnipeg, Canada. Participants were recruited into one of two groups; an intervention group and control group. The intervention group received two doses of 50,000 IU of vitamin D, one in the second trimester and one in the third trimester. A prenatal questionnaire was completed at the first visit. Cord blood was taken at birth and analysed for 25(OH)D. Participants returned at the time of their child's first birthday, where a follow up questionnaire and dental exam of the child were completed. The dental examiner was blinded to the vitamin D cord level. A p value ≤ 0.05 was significant. Results: 283 women were recruited (mean age 23.4 ± 5.6 years); 141 women were in the supplementation group, while 142 served as controls. Cord blood was drawn from 107 women in the intervention group and 109 controls. The mean 25(OH)D level was 49.6 ± 24.3 nmol/L. 175 women returned for the infant follow-up visit. The mean age of the children was 19.7 ± 8.1 months and 52% were male. Overall, 26.3% of children had ECC, and the mean decayed tooth (dt) score was 0.94 ± 2.16 teeth (range 0-16). There was no significant difference in prevalence of children with ECC between the intervention and control group (p=0.21). The 25(OH)D status 3 also did not significantly impact ECC (p=0.54). However, it was determined that mothers with higher cord 25(OH)D levels had infants with significantly lower dt scores (p=0.0011). Factors associated with ECC included, receiving government assistance (p=0.011), household income below $28 000 (p=0.0024), unemployment (p=0.00019), presence of enamel hypoplasia (p=0.0063) and developmental defects of enamel (p=0.0086), longer duration of being bottle-fed (p=0.0079) and age (p<0.0001). Conclusion: The vitamin D dose used in this study did not significantly increase the cord blood vitamin D status compared to the control group. No relationship was found to exist between the two groups and prevalence of ECC. However, significance was seen in an inverse relationship between 25(OH)D levels and the number of decayed primary teeth. Similarly designed studies, with an altered vitamin D regimen, need to be conducted in order to receive more conclusive results.
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    Dimensional stability of modified alginates
    (2017) Sinkala, Niza; França, Rodrigo; Todescan, Reynaldo
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    Direct Metal Laser Sintering Titanium Implants: X-ray Photoelectron Spectroscopy Analysis of Reprocessed Powder
    (2019) Shaker, Nader; Fernandes, Ana Carla; Fiuza, Cristina; França, Rodrigo
    Objectives: The aim of the study is to compare the chemical composition of two dental implants manufactured with two kinds of titanium alloys (Ti-6Al-4V) using a 3D printing technique called Direct Metal Laser Sintering (DMLS). The analyses involved two Ti-6Al-4V powders for DMLS: a) the control powder, obtained sealed directly from the manufacturer, not introduced to the production process; b) the experimental powder was recycled powder from the production line. Materials and Methods: The chemical composition of the control and experimental Titanium alloy powders and the dental implants were determined using X-ray photoelectron spectroscopy (XPS). Three different locations were selected on each of the four samples. Each location selected had 3 chemical composition readings at different depth; 0nm etch, 10nm etch, and 100nm etch. The readings represent the percent composition of the five major components of the titanium alloy powder surface; Oxygen, Carbon, Titanium, Aluminum, Vanadium. Results: XPS survey analyses show elevated presence of C in the 3D printed implants and no major difference among the major elements Ti, O, V. Conclusion: 3D printing of Root analogue implants (RAI) is a promising technique that can be used to replace non-restorable teeth as immediate implants.
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    The Effects on Microtensile Bond Strength in the Absence of Oxygen-Inhibited Layer and method of Etching
    (2019) Mikhlin, Dmitry; Fiuza, Cristina; França, Rodrigo
    Objective: Dental adhesives are relied upon to provide a strong and durable bond that will last, while also resisting dissociating forces, such as those experienced during polymerization shrinkage of composite resin restorations. The aim of this study is to determine the effects of anaerobic photo-curing of dental adhesives, by eliminating the oxygen-inhibited layer, on their mechanical properties; specifically, microtensile bond strength (μTBS). Materials and Methods: Forty permanent molars were divided among eight groups determined by a combination of one of two universal adhesive systems (Prime and Bone Elect, Scotchbond Universal), etching type (self-etch, total-etch), and curing conditions (aerobic, anaerobic). All bonded specimens were incubated in distilled water, half of which were stored for one month, and half for one year. Each specimen was cut into 1mm x 1mm in cross-section sticks, that were then used to test the μTBS of the adhesive. The specimens were subsequently evaluated under a light microscope to determine the location and type of failure. Results: Etching technique and curing conditions had a greater effect, while adhesive type has less influence, on the μTBS of the adhesive systems. Total-etch resulted in better bond strength under anerobic conditions, but performance decreased after one year. Prime Bond Elect presented the highest mean when used in aerobic curing technique associated with total etch (40.17MPa). The lowest value was observed with Scotchbond (SB) under anaerobic conditions and self-etching pre-treatment (11.58MPa). Conclusion: Within the limits of this study we can conclude that etching system and curing condition require further evaluation according to the adhesive system used in order to get the best adhesion results. As it stands, bond strength tends to be comparable, or better, under aerobic conditions. But improvements for better control of an anerobic environment could provide more accurate answers. Clinical significance: The evolution of universal adhesive represents the effort of manufacturers to facilitate the clinical procedures of adherence, but through these results, the choice of pre-treatments as well the curing process should be better evaluated
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    Exploring Trends in Children’s Oral Health in Winnipeg, Canada
    (2017) Truong, David; Schroth, Robert
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    Factors affecting the Degree of Conversion of 1 Universal Adhesives
    (2019) Rosenthal, Natalie; Fiuza, Christina; Haimeur, Asmaa; França, Rodrigo
    Universal adhesives are advertised as having a simplified application technique, however all still require multiple steps. This study tested the effect of solvent evaporation, oxygen inhibition layer (OIL) formation, and curing time on the degree of conversion (DC) for the following dental adhesives: All-Bond Universal Adhesive (AB), Prime & Bond Elect Universal Dental Adhesive (PB), iBond Universal (iBU), Scotchbond Universal (SBU), and One Coat 7.0 (OC). Adhesives were rubbed onto a glass slide for 20 s, then air blown for 5 s or 40 s. Some samples had an Epitex strip (Anaerobic) placed over the adhesive before polymerization, while the other group of samples were cured without an Epitex strip (Aerobic). Samples were light cured for 10 s, 20 s, or 40 s (n=4). The DC was measured using Fourier transmission infrared spectroscopy (FTIR). Results were analysed with 3 way ANOVA and Tukey post-hoc test (α=0.05). Curing under anaerobic conditions significantly increased the overall mean DC for all tested adhesives. A higher DC can be obtained by increasing solvent evaporation time for AB, iBU, SBU, and increasing curing time for all the adhesives, except iBU. Some universal adhesives benefit from a different application process than the manufacturers’ instructions.
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