Single posterior implant-supported restorations fabricated using a scannable healing abutment versus a conventional scan body: A randomized controlled trial.

STATEMENT OF PROBLEM: The use of a scannable healing abutment is a convenient option for fabricating implant-supported restorations (ISRs) with a digital workflow; however, clinical studies evaluating prosthetic efficacy are lacking. PURPOSE: The purpose of this randomized controlled trial was to investigate the prosthetic efficacy of definitive posterior single ISRs fabricated after scanning using a scannable healing abutment-scan peg (SHA-SP) in comparison with a conventional scan body (CSB). The time for data acquisition, quality of proximal and occlusal contacts, and relative occlusal force of ISRs were measured. MATERIAL AND METHODS: Twenty-four participants eligible for single ISRs to replace the mandibular first molar with adjacent and antagonist teeth present were randomly allocated to either a study group (n=12) receiving ISRs after intraoral scanning using an SHA-SP or a control group (n=12) receiving ISRs after intraoral scanning using CSB. During the surgical procedure, a prefabricated contoured scannable healing abutment was screwed to the implant in the SHA-SP group, while a custom-made healing abutment was used in the CSB group. After a healing period of 3 months, an intraoral scan was made, and the duration of data acquisition was recorded. The ISRs were milled from zirconia and evaluated for the quality of proximal and occlusal contacts using dental floss and shim stock, respectively. The relative occlusal forces of the ISRs and their contralateral natural teeth were measured using a digital occlusal analyzer. Statistical analysis was done using an independent sample t test for quantitative variables and a Pearson chi-squared test for qualitative variables between the tested groups (α=.05). RESULTS: The direct digital workflow using SHA-SP was statistically less time consuming than the CSB (P<.001). The 2 groups were statistically similar regarding the quality of the proximal contacts (P=.281) or occlusal contacts (P=.307) and the relative occlusal forces of ISRs (P=.315). The relative occlusal forces of the ISRs in both groups were significantly lower than those of their contralateral natural teeth (P<.001). CONCLUSIONS: Direct digital workflow using SHA-SP was more rapid, saving clinical chairside time, and produced proximal and occlusal contacts of comparable quality with those obtained with CSB. The relative occlusal forces of ISRs in both workflows were lower than their contralateral natural teeth.

Trueness of artificial teeth for CAD-CAM complete dentures fabricated with additive manufacturing implementing different denture base-tooth offset values: An in vitro study.

STATEMENT OF PROBLEM: Computer-aided design and computer-aided manufacturing (CAD-CAM) removable dentures have become popular. However, evaluations of the effect of denture base-tooth offset (DTO) values on the trueness of artificial teeth are lacking. PURPOSE: The purpose of this in vitro study was to digitally measure the trueness of the artificial teeth of CAD-CAM dentures fabricated with additive manufacturing using different DTO values and to determine the most accurate DTO value. MATERIAL AND METHODS: Seven study groups were formulated based on different DTO values, and 6 maxillary complete dentures were assigned to each group (n=42). A design software program was used to export the monoblock denture as control, the artificial teeth, and 7 different designs of denture bases with DTO values of 0.00, 0.01, 0.03, 0.05, 0.10, 0.15, and 0.20 mm. Denture bases were printed in denture base resin (Denture base RP; formlabs), artificial teeth were printed in tooth-shade resin (Denture teeth A2; formlabs), and both were then assembled and polymerized together. The dentures were scanned (InEos X5; Dentsply Sirona), scan data were imported in a measuring software program (GOM Inspect; GOM GmbH), and registration using local best fit was performed to align data. Color-coded maps for the surface comparison of each denture with the control denture scan were generated. Fitting center points were constructed for each artificial tooth, which were compared with their corresponding points on the data of the control scan. Multiple pairwise comparisons were performed after 1-way ANOVA to quantify and statistically evaluate the deviation values (α=.05). RESULTS: The 0.10-mm DTO group showed the lowest values when comparing artificial tooth deviations both individually and as types. On comparing the average deviations, statistically significant differences were identified among the 7 groups (P<.001). A nonstatistically significant difference was identified when the 0.10- and 0.05-mm DTO groups were compared. Lower deviation values were found in the premolars compared with the molars, in the incisors compared with the canines, and in posterior artificial teeth compared with anterior teeth. CONCLUSIONS: The 0.10-mm DTO value showed the highest trueness for the artificial teeth compared with the other DTO values tested in this study. The 0.05-mm DTO value is an alternative to the 0.10-mm DTO value for CAD-CAM dentures constructed by additive manufacturing. Anterior teeth of a CAD-CAM denture showed higher deviation values compared with posterior teeth.

Microbiological evaluation of conjunctival anopthalmic flora after using digital 3D-printed ocular prosthesis compared to conventional one: a randomized clinical trial.

BACKGROUND: This study aims to assess the influence of using 3D-printed acrylic resin versus conventional Poly-methyl methacrylate (PMMA) for fabricating ocular prostheses on the biofilm and microbial flora of anophthalmic socket. METHODS: A randomized controlled trial was designed as a parallel group study. Participants were allocated randomly into two groups: the control group, which received conventionally fabricated ocular prostheses (CG, n = 11), and the test group, which received digitally 3D-printed ocular prostheses (DG, n = 11). Microbiological analysis was conducted before prosthesis insertion and three months after using the ocular prosthesis. Swab samples were inoculated on blood agar, MacConkey's agar, and Sabouraud's dextrose agar (SDA) for isolating Gram-positive, Gram-negative, and fungal organisms, respectively. Subsequently, the plates were incubated at 37 degrees Celsius for 48 h. Additionally, a validated questionnaire was used for subjective clinical evaluation, including parameters such as comfort level, socket discharge, lacrimation, and frequency of lubrication for each ocular prosthesis patient in both groups. RESULTS: Test group (DG, n = 11) exhibited a positive, though statistically insignificant, difference (p > 0.001) in microbial growth when compared to the control group (CG, n = 11). A statistically significant difference was observed in comfort levels between the two groups, with more comfort level within group II (test group) patients. While parameters such as discharge amount, discharge location, lacrimation and lubrication frequency displayed statistically insignificant differences between the two groups, all parameters showed improved results after three months of prosthesis use. CONCLUSIONS: The choice of ocular prosthesis fabrication technique did not yield a statistically significant difference in anophthalmic flora. However, the 3D-printed acrylic resin, as an artificial eye material, displayed potential advantages in reducing the colonization of opportunistic pathogens. All subjective clinical evaluation parameters exhibited enhanced outcomes after three months of prosthesis use, emphasizing the need for an adaptation period during which patients complains are alleviated. In comparison with PMMA, 3D-printed acrylic resin showcased a certain degree of anti-colonization ability against pathogenic bacteria, along with a significant level of patient comfort, suggesting its potential as a promising material for ocular prostheses. TRIAL REGISTRATION: This parallel double-blinded RCT has been registered at ClinicalTrials.gov with identification number: NCT05584865, 18/10/2022.

Quantitative and qualitative assessment of the wear pattern of two attachment systems of dissimilar materials for mandibular implant-retained overdentures: an in-vitro study.

BACKGROUND: Attachment material is one of the contributing factors to the degree of wear of the attachment components in mandibular implant-retained overdentures. The purpose of this in vitro study was to compare the wear behavior of 2 different attachment systems of dissimilar materials in mandibular implant-retained overdentures by qualitative and quantitative methods. METHODS: Two attachment systems of different materials were utilized (n = 16); Titach (Dental Evolutions Inc, Beverly Hills, CA, USA) with a titanium-to-titanium interface and Locator R-Tx (Zest Anchors Inc, Escondido, CA, USA) with a titanium-to-nylon interface. One thousand cycles of overdenture insertion and removal simulating 1-year clinical use were performed. All matrices were removed from the overdentures and all patrices were unscrewed from the implants for wear assessment quantitively using a stereomicroscope and qualitatively using a scanning electron microscope. Data were analyzed by using an independent sample t test. RESULTS: After cyclic loading, stereomicroscopic findings showed that the Titach group had statistically significant higher wear value than the Locator R-Tx group (p < 0.001). Moreover, scanning electron microscopy images showed noticeable abrasion in Titach patrix at the area of highest convexity. However, the Locator R-Tx matrix displayed an apparent tear of rubber inserts. CONCLUSIONS: Titach attachment with the titanium-to-titanium interface revealed more wear than Locator R-Tx attachment with the titanium-to-nylon interface. Thus, the type of attachment material influences the degree of wear of the attachment components.

Positional transfer accuracy of titanium base implant abutment provided by two different scan body designs: an invitro study.

BACKGROUND: The variabilities in design and material of scan bodies have a major role in the positional transfer accuracy of implants. The purpose of this invitro study was to compare the 3D transfer accuracy (trueness and precision) of titanium base (TB) abutment position provided by 2 different scan bodies: one-piece scan body (SB) in comparison to two-piece healing abutment and scan peg (HA-SP). METHODS: A maxillary model with a dummy implant in the 2nd premolar (Proactive Tapered Implant; Neoss) was 3D printed and TB (Ti Neolink Mono; Neoss) was tightened on the implant and scanned by using a laboratory scanner (inEos X5; Dentsply Sirona) (reference scan). An SB (Elos Medtech) and an HA-SP (Neoss) were subsequently connected to the implant and were scanned 10 times each by using the same scanner (test scans). All the scans were exported as STL files and imported into CAD software where the TBs were formed. Test scans were superimposed on reference scans for transfer accuracy analysis using 3D metrology software (GOM Inspect; GOM GmbH) in terms of angular deviation in vertical and horizontal directions, linear deviation in each XYZ axis of TBs and total linear deviation in all axes. Statistical analysis was done using independent sample t test. When Levene's test for equality of variances was significant, Welch's t-test was used. (P value < 0.05) RESULTS: Significant differences were found amongst the tested groups in both angular and linear deviation in terms of trueness with less deviation values for the SB group (P < 0.001). For the precision, significant differences were found amongst the tested groups in angular deviation in vertical direction with less deviation value for the SB group compared to HA-SP group (P < 0.001). However, no significant difference was found between the tested groups regarding the angular deviation in horizontal direction (P = 1.000). Moreover, significant differences were found amongst the tested groups in linear deviations with less linear deviations in XYZ axes for SB compared to HA-SP group (P = 0.020, < 0.001, = 0.010 respectively). CONCLUSIONS: SB showed less angular and linear deviation values in the 3D positional transfer of TB than HA-SP indicating higher degree of accuracy of SB.

Disinfection of 3D-printed surgical guides using virgin coconut oil (in vitro study).

BACKGROUND/OBJECTIVE: Disinfection of a 3D-printed surgical guide is of utmost importance as it comes into contact with hard and soft tissue during implant placement so it poses a potential risk of pathogenic transmission. Methods used for disinfection in the surgical field should be reliable, practical, and safe for the instruments and the patients. The objectives of this study were to compare the antimicrobial potential of 100% Virgin Coconut Oil, 2% Glutaraldehyde, and 70% Ethyl Alcohol used to decontaminate 3D-printed surgical guides. MATERIALS AND METHODS: Thirty identical surgical guides were printed and cut into two halves (N = 60). Both halves were then contaminated with a defined amount of human saliva samples (2 ml). The first half (n = 30) was sub-grouped into three study groups which were immersed in one of the three disinfectants for 20 min as follows; group VCO was immersed in 100% Virgin Coconut Oil, group GA was immersed in 2% Glutaraldehyde, and group EA was immersed in 70% Ethyl Alcohol. The second half (n* = 30) was sub-grouped into three control groups which were immersed in sterile distilled water as follows group VCO*, group GA*, and group EA*. The microbial count was expressed as colony-forming units per plate and the comparison of the antimicrobial potential of the three tested disinfectants between the three study and three control groups was done using the One-Way ANOVA test. RESULTS: The culture results of three study groups revealed no bacterial growth with the highest % of reduction in the mean microbial count of the oral microorganisms (about100%) and an uncountable bacterial growth was shown between the three control groups (more than 100 CFU/plate) representing the baseline of the oral microorganisms. Therefore; statistically significant differences were found between the three control and three study groups (P < .001). CONCLUSION: The antimicrobial potential of Virgin Coconut Oil was comparable and equivalent to Glutaraldehyde and Ethyl Alcohol with a significant inhibitory action against oral pathogens.

The microbiological effect of virgin coconut oil on the morphological and volumetric dimensional changes of 3D printed surgical guides (in vitro study).

BACKGROUND/OBJECTIVES: Disinfection of surgical guides is mandatory for intraoperative use. Virgin Coconut Oil may be a potent alternative disinfectant; however, its effect has not been fully discussed in dentistry. The objectives of this study were to compare the morphological and the volumetric dimensional changes of 3D printed surgical guides after immersion in three disinfectants: 100%Virgin Coconut Oil, 2% Glutaraldehyde, and 70% Ethyl Alcohol and to assess the antimicrobial effectiveness of the tested disinfectants. MATERIALS AND METHODS: A surgical guide was designed using open platform software to print thirty guides and then cut them into two halves (N = 60). Pre-disinfection scans of the first half of the three study groups (n = 30) were performed using Cone-beam Computed Tomography, then immersed for 20 min in three disinfectants as follows: group VCO was immersed in 100% Virgin Coconut Oil, group GA was immersed in 2% Glutaraldehyde, and group EA was immersed in 70% Ethyl Alcohol. Post-disinfection scans of the first half of the three study groups (n = 30) were performed and then compared morphologically and volumetrically using an analyzing software program The second half of the three control groups (n* = 30) were soaked for 20 min in sterile distilled water as follows: group VCO*, group GA*, and group EA* for the assessment of the antimicrobial effectiveness of the three tested disinfectants. RESULTS: At the morphological assessment of the dimensional changes, group VCO were the most accurate with the lowest mean deviation value of 0.12 ± 0.02 mm and root mean square value of 0.12 mm, group GA and group EA were less accurate with mean deviation value of = 0.22 ± 0.05 mm and = 0.19 ± 0.03 mm and root mean square value of 0.22 and 0.20 respectively (p < 0.001). At the volumetric assessment, group VCO showed lower volumetric changes with a mean deviation value of 0.17 ± 0.10 mm, root mean square value of 0.19 mm, than group GA with mean deviation value of 0.23 ± 0.10 mm, root mean square value of 0.25 mm and group EA with mean deviation value of 0.27 ± 0.11 mm, root mean square value of 0.29 mm, however, no statistically significant differences were found between the three study groups (p = 0.10). The antimicrobial effectiveness of the three tested disinfectants showed a hundred percent (100%) reduction in the total microbial count in the first half of the three study groups treated with the three disinfectants revealing no bacterial growth, however, statistically significant differences were found between the second half of the three control and the first half of the three study groups. (p < 0.001). CONCLUSIONS: Virgin Coconut Oil showed higher morphological dimensional accuracy of the tested surgical guides than Glutaraldehyde and Ethyl Alcohol without causing any volumetric dimensional changes in the 3D printed surgical guides after disinfection for 20 min and the antimicrobial effectiveness was the same between the three tested disinfectants without showing any microbial growth.

Modified biblock versus monoblock mandibular advancement appliances for treatment of obstructive sleep apnea: A randomized controlled trial.

STATEMENT OF PROBLEM: The high prevalence of obstructive sleep apnea represents a serious public health problem. Oral appliances have gained wide acceptance among patients diagnosed with obstructive sleep apnea, who should wear them every night. A comfortable oral appliance is mandatory for successful treatment outcomes. PURPOSE: The purpose of this randomized controlled trial was the assessment of the influence of 2 different designs of the mandibular advancement appliance (MAA), modified biblock and monoblock, for the management of obstructive sleep apnea. MATERIAL AND METHODS: The study was designed as a prospective 2-arm randomized controlled clinical trial conducted in parallel. Twenty participants (aged 40 ±7.5 years) diagnosed with moderate obstructive sleep apnea were randomly assigned to a control group (n=10), receiving monoblock MAA, and a study group (n=10), receiving modified biblock MAA with elastics. Both appliances were fabricated by using computer-aided design and computer-aided manufacture (CAD-CAM) technology at different mandibular advancement levels (MALs): 50% and 75% of maximum MAL. A total of 60 cone beam computed tomography scans, 60 overnight full polysomnography sleep tests, 60 STOP-Bang questionnaires, and 40 Usability of Sleep Apnea Equipment-Oral Appliance (USE-OA) questionnaires were collected and analyzed blindly at baseline (initial visit), 50% MAL (3 months), and 75% MAL (6 months). The main outcome measures were the upper airway volume, linear anteroposterior and cross-sectional airway measurements, Apnea Hypopnea Index, Respiratory Disturbance Index, STOP-Bang questionnaire scoring, and USE-OA questionnaire scoring. Nonparametric statistical analysis was performed by using a statistical software program (α=.05). With a beta error accepted of up to 20%, the power of the study was 80%. RESULTS: At 75% MAL, the percentage change in upper airway volumetric measurements showed a favorable increase: biblock group (115%) and monoblock group (42%), with a statistically significant difference (P=.001). The linear anteroposterior airway measurements and the percentage change in cross-sectional airway measurements were statistically similar: biblock group (80%) and (75%) monoblock group (60%), (54%) (P=.450, P=.151, respectively). The percentage change in the Apnea Hypopnea Index significantly decreased: biblock group (-89%) and monoblock group (-54%) (P<.001). The percentage change in the Respiratory Disturbance Index decreased: biblock group (-78%) and monoblock group (-62%) (P<.023). From the STOP-Bang questionnaire scoring, 100% of both groups showed low risk for obstructive sleep apnea at 75% MAL. From the satisfaction scoring on the USE-OA questionnaire, the biblock group was 100% strong satisfaction and the monoblock group was 50% satisfaction and 50% fairly satisfied. CONCLUSIONS: The modified biblock MAA with elastics showed significant improvements in patients diagnosed with obstructive sleep apnea regarding upper airway measurements and full polysomnography vital parameters when compared with monoblock MAA.