Department of Prosthodontics

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An investigation into the compatibility of some irreversible hydrorocolloid impression materials and dental gypsum products
(University of the Western Cape, 1983) Owen, Christopher Peter; Wildlng, R J C
This was based on a similar procedure described by Morrow et al (1971) but differed ln several respects. By photographing the gypsum casts through a stereomicroscope at constant signification and using a constant light source, It was possible to produce a consistent, photomicrograph. The gypsum casts were photographed with black-and-white flu, and high-contrast prints obtained of the best-reproduced section of the 01050 mm line. These prints were then subjected to an evaluation procedure using four evaluators who gave a score to the quality of reproduction of the line on a rating scale of I to 4. A11 prints were scored three times by each evaluator, and the sums of these three scores were subjected to statistical analysis. The statistical analysis showed this procedure to be consistent, and that it could be expected to be repeatable. On the basis of this analysis, it was found that one alginate was clearly superior to all others, and that it was possibe to distinguish a further group of combinations within the group that reproduced the 0r050 mm line. Some of the alginate materials were treated with fixing solutions of varying concentrations of potassium sulphate and alum. The results obtained were varied, sometimes producing marked improvement, sometimes deterioration ln the surface quality of the subsequent gypsum cases. None of the treated materials could be improved to the extent of equating then with the best of the naturally compatible combinations
The strength of provisional crown and fixed partial denture (bridge ) materials
(University of Western Cape, 1988) Osman, Yusuf; Owen, C. P
Provisional crown and fixed partial denture (bridge) materials are often referred to as "temporary" materials. The Oxford Dictionary defines temporary as "lasting, or meant to last only for a time; not permanent". Yet for crown and fixed partial denture restorations a provisional restoration is crucial to the final restoration. It is, or should be, a preview of the final prosthesis.
The fracture resistance of structurally compromised roots using different post systems
(University of the Western Cape, 2002) Solomon, Charlene S; Osman, Y.I
The structurally compromised root presents a great challenge to the restorative dentist. The amount of tooth structure that remains after endodontic therapy and post preparation is of prime importance and the strength of an endodontically treated tooth is directly related to the amount of residual dentine. Post and cores are often required with pulpless teeth to provide retention and resistance form for the final restoration. Aim: The purpose of this in vitro study is to investigate the fracture resistance of structurally compromised teeth using four dynamically different post and core systems in the rehabilitation process. Method: After the crowns were removed one specimens were then randomly divided into four groups of 25 teeth each as follow: Group A: morphologic cast post and core; Group B: resin reinforced glass-fibre post and composite core; Group C: resin reinforced carbon fibre post with composite core and Group D: resin reinforced prefabricated parallelsided titanium post and composite core. All specimens were subjected to an increasing palatal force until fracture occurred. Results: Results showed cast post and cores to have higher fracture loads that the resin reinforced groups (p< 0). The difference in fracture resistance between the three reinforced groups was found not to be significant (p > 0). Conclusions: Significantly higher fracture thresholds were obtained in the cast post-and-core group. The reinforced group (with composite cores) showed failure of the post-core interface before the fracture of the tooth occurred. This failure occurred in response to acceptable high loads. The Luminex@ light transmitting posts can help strengthen weakened, endodontically treated teeth by the combined bonding action of dentine bonding agents and composite resin restorative material.
The effects of diferent reinforcements on the fracture toughness of provisional restorative materials
(University of the Western Cape, 2006) Overturf, Jan Hendrik; Geerts, Greta; Dept. of Prosthodontics; Faculty of Dentistry
One of the most critical aspects of successful crown and bridgework is temporary restorations. Failure of temporary restoratins often affects the patient's confidence and mau result in unscheduled appointments for repair. This study compared the the fracture toughness of two materials commonly used to fabricate provisional restorations, namely Coldpac, a polymethyl methacrylate and Protemp 3 Garant, a bis-acryl composite. It also compard the fracture toughness of the two materials when reinforced with stainless steel wire, glass fibers and polythylene fibers.
Disinfection procedures: effects on the dimensional accuracy of Gypsum casts
(University of the Western Cape, 2007) Salih, Mayson; Wilson, V.J.; Osman, Yusuf I.; Dept. of Prosthodontics; Faculty of Dentistry
The aim of the study was to assess the dimensional accuracy of Gypsum models following chemical disinfection of the impressions and to compare it with the accuracy of gypsum models exposed to microwave irradiation disinfection. Results indicated that the dimensional accuracy of the gypsum models disinfected in a microwave oven did not differ significantly from models in the control group. Except for models produced from SS white (SS White group, England) impressions where models irradiated in microwave exhibit significant improvement in the dimensional accuracy when compared with control group.
The efficacy of rotary and manual instruments in root canal debridement.
(University of the Western Cape, 2009) Madlabane, Duduzile; Osman, Y.I.
It has been shown thot the use of both manual and rotary instruments result in the formation of o smear layer and debris during root canal treatment. The amount thot is formed depends on the type of instrumentation used as well as the force applied. Aim: The purposes of this study were. To use the scanning electron microscope to compare the cleanliness of the root canal walls following rotary and manual debridement methods 2. To assess the transportation of the apical port of the root canal orifice when using different instrumentation techniques. Materials and Methods: Endodontic treatment was performed on extracted maxillary central incisors following exportation and debridement using the Protaper@ nickel titanium files and K-files. The teeth were randomly divided into three groups. Endodontic therapy performed simulated the clinical procedures, in which the teeth were extirpated using o barbed broach to remove the necrotic pulp. Pre-operative periodical radiographs were used to determine the working length. Root canals were debrided using the two filing methods, with copious irrigation using Sodium hypochlorite solution in o disposable syringe with o 27 gauge needle. A follow up radiograph with o master apicol file in position was used to verify complete debridement in the apicol third of the canal. The teeth were then sectioned vertically using o diamond bur to create an initial groove and then split apart using q flat plastic instrument to separate the sections and to avoid contamination of the sections. These sectioned portions were then studied under o scanning electron microscope. The smear layer as well as the amount of debris was evaluated.
The efficacy of rotary and manual instruments in root canal debridement
(2009) Madlabane, Duduzile; Osman, Yusuf I.
It has been shown that the use of both manual and rotary instruments result in the formation of a smear layer and debris during root canal treatment. The amount that is formed depends on the type of instrumentation used as well as the force applied. The purposes of this study were to use the scanning electron microscope to compare the cleanliness of the root canal walls following rotary and manual debridement methods, to assess the transportation of the apical part of the root canal orifice when using different instrumentation techniques. Endodontic treatment was performed on extracted maxillary central incisors following extirpation and debridement using the Protaper® nickel titanium files and K-files. The teeth were randomly divided into three groups. Endodontic therapy performed simulated the clinical procedures, in which the teeth were extirpated using a barbed broach to remove the necrotic pulp. Pre-operative periapical radiographs were used to determine the working length. Root canals were debrided using the two filing methods, with copious irrigation using Sodium hypochlorite solution in a disposable syringe with a 27 gauge needle. A follow up radiograph with a master apical file in position was used to verify complete debridement in the apical third of the anal. The teeth were then sectioned vertically using a diamond bur to create an initial groove and then split apart using a flat plastic instrument to separate the sections and to avoid contamination of the sections. These sectioned portions were then studied under a scanning electron microscope. The mear layer as well as the amount of debris was evaluated. The assessment of residual debris and smear layer formed, were assigned numbers and tabulated. All three areas of the root canal were compared against each other. The sectioned apical third of the root canal was also studied for the presence or absence of apical transportation. From the present study, it was found that both the nickel-titanium rotary files and stainless steel hand files produced some smear layer and there was some residual debris left in uninstrumented areas of the root canal. However, it was shown that there was more smear layer formation when using nickel-titanium rotary files compared to that formed using hand files. When assessed for the presence of apical transportation, it was found that both types of instrumentation resulted in some degree of transportation, however, with rotary files, the canals remained largely centralized with transportation clearly visible in hand instrumented canals.
The reliability and validity of the facial anthropological device
(2010) Rayner, Monique Jo Anne; Wilson, V. J.
It is generally agreed that the most troublesome procedure during the fabrication of complete dentures is the measurement of the Vertical Dimension at rest. The aim of this study was to test the reliability and validity of a new instrument called the Facial Anthropological Device (FAD). The measurements recorded were compared to the Willis gauge (being the gold standard) and dividers, which are mechanical aids used to quantify lower third facial height during denture construction. This thesis presents data on 35 edentulous and 35 dentate patients in the age range of 30 to 70 years, who presented at the University of the Western Cape Dental faculty.The FAD incorporates a ‘spirit‐level’ and uses more anatomical landmarks than any other measuring device noted in the literature. It measures facial landmarks in the midline and is not only used to measure the vertical dimension of the face, but with further research, may also be used in forensic studies. The Willis gauge is designed to measure the distance from the lower border of the septum of the nose to the lower border of the chin, and the distance from the outer canthus of the eye to the corner of the relaxed lip with the teeth in occlusion. The dividers measures two arbitrary points on the face.The study showed that the FAD was most similar to the Willis gauge where reliability and reproducibility was compared. There were no statistically significant differences (P > 0.05) between the two devices.The FAD has shown to be a reliable and valid instrument that could be used to measure facial vertical dimension in the edentulous as well as dentate patients, however with some modifications to its design.
Interceptive orthodontic treatment need among children attending dental clinics in the Tygerberg sub-district
(2013) Marais, Amanda Karien; Hudson, A.; Mohamed, N.
Background In the Western-Cape province, orthodontic treatment provided to government patients is limited to tertiary hospitals such as the Tygerberg Oral Health Centre (TOHC). This results in growing waiting lists which place a huge strain on resources of the facility. Objectives To determine: 1. The prevalence of malocclusion among 7-to-10-year-old children examined at dental clinics within the Tygerberg sub-district. 2. The types of malocclusion they present with. 3. Which of these malocclusions can be treated with interceptive orthodontic treatment. Methods An analytical, descriptive, cross-sectional study was carried out and quantitative methods were used to achieve the aim and objectives. The study sample consisted of 100 children, 46 male and 54 female, from Bellville and Bishop Lavis dental clinics. Dental examinations were done by one examiner on children between the ages of 7 and 10 years. Dental problems were identified which, if left untreated, could result in the need for more complex orthodontic treatment at a later stage. All the necessary ethical clearance was obtained. Results The results showed that there is a very large interceptive orthodontic treatment need (79%) at these clinics. A large proportion (70%) presented with detrimental habits. Thumbsucking was more prevalent among girls than boys. Other problems like mouthbreathing, lip wedging, deep bite, asymmetrical mobility of primary teeth, rotated lateral incisors and crossbites were found. The biggest concern was that 71% of the children had early loss of primary teeth and only 5% of children received restorations, resulting in a high prevalence of unfavourable molar relationships. All of these should be addressed early, thereby preventing the development of complex orthodontic problems or skeletal discrepancies. iv Conclusion Interceptive and preventive orthodontic treatment should be regarded as a primary health centre service, as it may reduce the need for costly fixed orthodontic treatment. The study showed that urgent intervention is necessary from the Department of Health to address this issue.
Complete denture occlusion: intra and inter observer analysis
(University of Western Cape, 2014) Mpungose, Sandile Khayalethu Derrick; Geerts, Greta
Aim: The aim of this study was to investigate the accuracy, intra- and inter-observer reliability of identifying occlusal markings made by articulating paper on complete dentures intra-orally. Methods: A series of photographs of 14 tissue borne complete dentures with occlusal markings was obtained. Articulating paper was used intra-orally at the delivery visit to make the occlusal markings. The denture sets were divided into two groups. Group 1 comprised pictures of the 14 complete lower dentures on their own, and group 2 comprised pictures of the same 14 lower dentures together with their opposing upper denture. The two groups of images were loaded into a Microsoft PowerPoint presentation as well as Keynote. Two experienced observers analysed the complete dentures independently and noted the number and distribution of the markings that they felt required adjustment. They differed, but discussed these and reached consensus. These data served as the control. Three groups of observers (10 per group) were then asked to analyse the occlusal markings of the 2 groups of denture images twice, with a two-week interval between each assessment. Before each subsequent assessment, the images were randomised by means of computer-generated random number sequence. The mean number of markings was established for each group and compared with the control mean. Intra-rater reliability was established by comparing the difference of the means of sequential observations for each rater by establishing the z-value. Inter-rater reliability within each group was established by means of analysis of variance. Results: Considering all the data, in only 17 instances (of the possible 60), did observers’ mean scores not differ from the control mean scores with good intra-rater reliability. In all other 43 instances the observers’ mean scores differed from the control mean scores and/or displayed poor intra-rater reliability. Considerable variation in inter-rater reliability was also found within every group of observers. Conclusion: The results indicate that observers are generally unable to reliably identify occlusal markings warranting occlusal adjustment, made by articulating paper on a lower complete denture. Clinical significance: Articulating paper should not be used intra-orally when delivering removable complete dentures.
An in-vitro comparative micro-computed tomographic evaluation of three obturation systems
(University of the Western Cape, 2017) Kabini, S.N.; Moodley, D.; Patel, N.; Parker, M.E.
Gaps or voids between walls of root canal and obturation material may lead to re-infection of the obturated root canal. Therefore, adaptation of the obturation material to dentine walls is essential for the success of root canal treatment.
An in-vitro study of the physical properties of core build-up materials
(University of the Western Cape, 2017) Asia, Winifred; Patel, N.; Moodley, D.
The aim of this study was to evaluate and compare the physical properties of two core build-up materials (ParaCore and CoreXflow) and compare this to conventional composite material (Filtek Supreme Plus and SDR Flow) used as core build-up material.
A comparative study between thermoplastic and conventional removable partial denture designs
(University of the Western Cape, 2019) Farao, Warren Emile; Geerts, Greta
Three dental laboratories in the Cape Town Metropole that were known to fabricate “flexible” or NMCDs for dental practices were identified and were invited to participate in the study. Their participation consisted of emailing photographs of completed metal-frame, acrylic and flexible RPDs and their casts prior to sending them to the practices for delivery to patients. Specimens were collected until a total of 20 metal-frame, 20 acrylic resin and 20 flexible RPDs were received. A design was drawn for each submitted RPD. For each RPD, an “ideal” design was drawn, using the image of the cast. This was done by two observers, who are experienced members of staff in the Department of Restorative Dentistry (Prosthetics), independently. The designs from both observers were later compared for similarity. Where differences existed in the designs, these were resolved by means of discussion until agreement was reached. Each ideal design served as the control for each clinical design.The number of rests, their configuration, the type of support, number of clasps, the presence of indirect retention, cross-arch stabilization, the number of teeth whose periodontal tissues were covered by design components for each design among the different denture type groups, and corresponding control designs were identified and reported. The ratios of teeth replaced/teeth covered per denture type groups and per classification, and corresponding control designs were compared.
Efficacy of Low-Level Laser Therapy In Treatment of Temporomandibular Myalgia: A Randomized Controlled trial.
(University of the Western Cape, 2022) Netshilindi, Neo, E.; Geerts, G.
Background: Objective: The objective of the study was to compare pain and functional limitation of temporomandibular myalgia patients, before and after low-level-laser treatment (LLLT). Methods: This was a prospective, randomized, placebo-controlled, triple-blinded clinical study. Patients diagnosed with temporomandibular myalgia according to the DC/TMD protocol were recruited from the TMD clinic of the Mitchell’s Plain Oral Health Centre. Treatment was performed using diode laser (Sirolaser, Dentsply Sirona). The 3 regions of the masseter and temporalis muscles were treated bilaterally with a dose of 8J/cm2 per region. Pain and function were assessed using pain-free opening, numeric rating scales (NRS), Characteristic Pain Intensity Scores (CPIS), Interference Score (IS), and Jaw Functional Limitation Scale (JFLS) at the first and last LLLT and at 4-week recall (intervals 1, 2, 3). Statistical analysis was done by means of explorative categorical principal and multivariate interdependent analysis. Results: Seventeen (15 females) of the 19 patients completed the LLLT (89% retention). Mean pain-free opening increased for both treatment (A) and placebo (B) group (35.0 mm to 41.2mm; 34.8 mm to 37.9 mm respectively). This increase was not statistically significant between groups. All patients from group A reported less (n = 7) or similar pain (n = 2) with opening after treatment. For group B, 4 patients reported improvement, 1 no change and 3 worse pain with opening after treatment. Mean CPIS for groups A and B for the 3 time intervals were 69.63, 47.41, 34.07 and 70.42, 55.71, 52.92 respectively. Mean IS were 53.67, 32.22, 25.56 and 49.88, 40.48, 22.88 respectively. Global scores calculated from the JFLS for groups A and B for the 3 time intervals were 4.368, 3.380, 3.189 and 4.760, 4.396, 5.046 respectively. No effect between groups and no effect of time was statistically significant. Conclusions: Within the limitations of this trial, the laser group reported more improvement in mobility, pain experience and function but these improvements were not statistically significant.
Comparing cytocompatibility of two fluoride-containing solutions and two resin-based restorative materials—a pilot study
(Frontiers Media SA, 2024) Mulder, Riaan; Noordien, Naeemah; Potgieter, Nicoline
Background: Cytocompatibility should always be considered, especially if the surface of treated carious lesions is close to soft tissue or is accidentally exposed to the oral soft tissue by the clinician. Methods: The aim of the present study was to compare the cytocompatibility of two fluoride-containing liquids and two resin-containing restorative materials with buccal mucosa fibroblasts. The fluoride-containing materials were silver diamine fluoride and water-based silver fluoride. Results: The statistical analysis was completed by comparing the positive control growth of the buccal mucosa fibroblasts to the growth of cells exposed to various materials. The one-way ANOVA with Tukey’s HSD result was completed. All the assessed materials compared to the control wells for both the 24 and 48 h time intervals indicated a significant cytocompatibility result, except for the test wells with Stela (SDI) at the 24 h time interval. There was no significant difference between the step 2 liquids and the two dental materials in cytocompatibility at the 24 h interval. All four materials indicated no significant differences between the cytocompatibility of any dental materials for 48 h. Conclusion: The cytocompatibility assessment for Riva Star and Riva Star Aqua with the direct method in a full dispensing drop is not viable for step 1 of the fluoride-containing liquids. The use of Stela Light Cure is a suitable material that will be in contact with buccal mucosa as it showed potential for increased cytocompatibility compared to Riva Light Cure. Riva Star Aqua is more cytocompatible than Riva Star.

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