Purpose was to evaluate the retention of thermo-elastic acrylic resin versus conventional heat cured acrylic resin. Material and Methods: Ten completely edentulous patients were divided into two groups, patients in this first group received one maxillary and mandibular complete denture made of conventional heat cured acrylic resin, and wearing it for one month, and then the mandibular denture was replaced by another one whose denture base was made of thermoelastic acrylic resin. Patients were instructed to wear the dentures for one month before evaluation of retention. While in the second group, the other patients received one maxillary conventional heat cured acrylic complete denture and one mandibular thermo-elastic denture, and wearing it for one month, and then the mandibular denture was replaced by another one whose denture base was made of conventional acrylic resin. Patients were instructed to wear the dentures for one month before evaluation of retention. Results: The results of this study showed thermo-elastic mandibular denture base had recorded statistically significant higher retention mean value than conventional cured mandibular denture base p ≤ 0.001. Conclusion: Thermo-elastic heat cured acrylic resin (versacryl) denture exhibit more retention than that of the conventional heat cured acrylic denture.

Purpose: The aim of the study was to assess microbial adherence on maxillary complete denture carried by different fabrication techniques; the conventional and CAD/CAM (computer-aided design and computer-aided manufacturing) techniques. Material and methods: Ten completely edentulous patients were selected and divided into randomly two equal groups: group I, patients received maxillary and mandibular complete dentures made of conventional heat-cured acrylic resin and group II, patients received maxillary CAD/CAM complete denture and mandibular conventional complete denture. Assessment of the microbial colonization of maxillary dentures for both groups was carried out after 3, 6 and 9 months after denture insertion. The tested microorganisms are Candida albicans (C. albicans), Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans) and Escherichia coli (E. coli). results: Comparison of microbial colonization count represented in colony forming unit per ml (CFU/ml). Change between group I and group II revealed that, group II has statistically significant lower CFU/ml than group I for all the tested microorganisms during the study period (P-value <0.05) except for E. coli after 3 months the difference between both groups was statistically non significant (p = 0.139). And there was a gradual increase in the microbial count during the time of using both types of dentures. Conclusion: CAD/CAM dentures showed less microbial colonization than conventional heat cure acrylic resin dentures. Further short-term and long-term clinical studies are needed to validate CAD/CAM technology in complete denture prosthodontics. IntroduCtIon Poor oral health can adversely affect the mental, social, physical and general systemic health of denture wearers (1). The condition of oral and denture hygiene is very important in controlling microorganisms

Aim of the study: to evaluate the effect of flexible denture base materials on retention of complete denture. Material & methods:Seven completely edentulous patients with age ranged between 45 and 55 years were selected for this study. Complete conventional heat cured acrylic resin dentures were constructed for all patients .The retention was evaluated after one and three months from dentures delivery. Another set of flexible denture base was constructed for all patients then the retention were evaluated after one and three months from denture delivery. Results:The result of the study revealed that there were statistically significant differences in the retention between heat and flexible cured acrylic resin denture bases (p value <0.001). Conclusion: from This study it is concluded that the flexible heat acrylic resin denture base improve retention of complete dentures.

Objectives: This study was designed to evaluate the antimicrobial effect of alternative disinfection methods of heat cured acrylic resin and thermoplastic resin denture base materials and to investigate the porosity resulting from disinfection by these methods. Material and Methods: Disc specimens of heat cured acrylic resin and thermoplastic resin were fabricated and divided into four groups for each denture base material according to the disinfection method. The specimens were contaminated in vitro by standardized suspensions of Candida albicans (C. albicans).The following test agents were used: distilled water (as a control group), 5% sodium hypochlorite (NaOCl), 100% white vinegar and 650 W microwave (MW) energy. After the disinfection procedure, the number of viable microbial cells was counted in CFU/ml. Porosities of acrylic resin and thermoplastic resin specimens were evaluated with Scanning Electron Microscope (SEM) after one month of daily exposure to disinfection. Results: ANOVA test showed that, there was a statistical significant difference among the tested treatment agents against C. albicans in each denture base material(P≤ 0.05). Post Hoc test showed a statistical significant difference between the control samples and the other disinfected samples in the microbial count, however, there was no statistical significant difference among the tested methods of disinfection (P>0.05).Regarding porosity area percentage, there was a statistical significant difference among the tested methods of disinfection (P≤ 0.05), where, 100% white vinegar showed the highest porosities followed by NaOCl then the MW disinfection and the least is the control group. Regarding comparison between the two denture base materials, thermoplastic resin showed statistically significant lower microbial adherence as well as lower porosity area percentage than heat cured acrylic resin(P≤ 0.05). Conclusion: All the tested disinfection methods shown to be efficient against C. albicans. Thermoplastic resin demonstrated lower microbial adherence than heat cured acrylic resin and lower porosity area percentages.

Purpose: This study was conducted to compare between maxillary implant-supported overdentures retained by Telescopic and ball and socket regarding retention. Material and Methods: seven male patients had completely edentulous maxilla free from any systemic disease that might affect bone metabolism was selected to participate in this study. Each patient received four dental implants in the edentulous maxilla using computer guided surgical stent. Implants had enough antero-posterior spread so that load can be distributed equally. Once the implant osseointegration appears to be satisfactory, the maxillary four implants were loaded with two different attachments as follow; Group I: All patients received maxillary single denture retained with ball and socket attachments and used it for three months. Group II: After a wash up period of two weeks, all patients received another newly constructed maxillary single denture retained with telescopic attachments and used it for another three months. Retention of both groups was measured using universal testing machine. The assessment was made at time of insertion, one month and three months follow-up period. Results: Group II showed higher retention values compared to Group I. Conclusion: ball and socket attachment as well as telescopic attachment showed decrease in retention but telescopic attachment revealed a higher score than ball attachment due to frictional retention.

Aim: This study aimed to compare between mini implants and short implants supported overdentures in completely edentulous patients with atrophic ridges not suitable for conventional implants. Materials and methods: Ten completely edentulous patients with severely resorbed mandible and age ranged between 55 and 60 years were selected for this study. Complete heat cured acrylic resin dentures were constructed for all patients. Patients were divided into two groups, each group had five edentulous patients, In Group I, each patient received two mandibular mini-implants at the canine site with a standard diameter 2.5 mm and standard length 10 mm, while in Group II, each patient received two mandibular short implants at the canine site with standard diameter 3.4 mm and standard length 10 mm. All implants in both groups were placed following immediate loading protocol. Patients were recalled for a follow-up period of 1 year, evaluating implants clinically for pocket depth and gingival index at baseline, then 3, 6 and 9 months intervals, and evaluating bone height loss radiographically at baseline, then 6, 9 and 12 months intervals. Results: Pocket depth and crestal bone height loss increased in patients using short implants than patients using mini implants, while gingival index parameter in all patients was not affected by using the two types of implants. Conclusion: Mini dental implants have a favorable effect on the supporting structure than short dental implants in both clinical and radiographic evaluation.

Purpose : the present study was assess the outcome of different occlusal concepts which are balanced occlusion and canine guided occlusion on the masticatory efficiency of muscles of mastication in implant supported mandibular overdentures wearers. Material and method: Ten totally edentulous patients were chosen for this study, aged 50 to 60 years old. All patients free from any systematic dieses. The patients were divided according to the treatment protocol into two groups; all patients wore denture with intra oral adjustment as a control group, (GI) five patients wore denture with bilateral balanced occlusion and (GII) five patients wore denture with canine guided occlusion. All patients were submitted to masticatory efficiency test, after one month by using different textures of foods. All data selected during the study were evaluated using ANOVA followed by Tukey's post hoc test using LSD test. P< 0.05 was considered statistically significant. Results: with soft food, there was no significant difference among the three groups, while for chewing hard type of food; the greatest mean was recorded in occlusion after oral adjustment, whereas the lowest mean was recorded in bilateral balanced occlusion. Conclusion: The two groups selected in the study, bilateral balanced occlusion as balanced concept and as a non-balanced concept canine guided occlusion both can be considered for usage effectively in implant retained overdentures without disturbing chewing efficiency.

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