Influence of different palatal morphologies on the accuracy of intraoral scanning of the edentulous maxilla: A three-dimensional analysis.

PURPOSE: This study investigated the influence of different palatal morphologies on the accuracy of intraoral scanning (TRIOS 4) of edentulous maxillae. METHODS: Six typodonts were fabricated for different palatal morphologies with flat (F), medium (M), and deep (D) palates, with palatal wrinkles (W), or smooth palates (S), resulting in six groups: WF, WM, WD and SF, SM, SD. Ten scans were performed for each group; standard tessellation language files obtained were imported into a software to measure trueness and precision in micrometer. Trueness was calculated as the mean of the standard deviation values obtained by superimposing each scan onto the reference scan. Precision was achieved by overlapping each scan with that with the best trueness in the group. Descriptive and post-hoc analyses were conducted. RESULTS: The mean values for trueness were as follows: WM=48.7±4.7, WD=161.7±18.4, WF=85.9±16, SM=48.1±2.4, SD=349.9±8.8, and SF=349.1±25.5. The precision values were as follows: WM=46.7±7.3, WD=46.9±9, WF=48.9±6.7, SM=46±2.7, SD=105.9±17.4, SF=72.6±10.8. Significant differences were observed for trueness between SM and SD (P < 0.001), SM and SF (P < 0.001), and WF and SF (P = 0.003); whereas for precision, significant differences were reported between WD and SD (P = 0.015). Regarding trueness and precision, no difference was found between WM and SM (P = 1.0). CONCLUSIONS: Medium palatal depth showed the best accuracy. The mean accuracy values were within the clinical acceptability thresholds for all palatal morphologies. The presence of rugae improved the precision of deeper palates and the trueness of flat palates. No differences were observed in the medium palates with or without rugae.

Digital denture with mucostatic base and functional borders: A cast-free digital technique.

Digital complete dentures fabricated using a mucostatic impression, like intraoral scans, are desirable for their beneficial effect on long-term residual ridge stability but may have less retention than those fabricated with a mucocompressive impression. Border molding procedure may improve initial retention, thus favoring adaptation to new dentures, especially in cases where neuromuscular dysfunctions may diminish the patient's ability to cope with adapting to existing motor patterns or learn new ones. However, a mucocompressive impression may cause higher residual ridge resorption, thus resulting in a retention decrease over time. A desirable combination would be a digital denture with a mucostatic intaglio surface obtained from intraoral scans and functional borders. A cast-free digital workflow for that is demonstrated in this technical report.

Assessment of distortion of intraoral scans of edentulous mandibular arch made with a 2-step scanning strategy: A clinical study.

STATEMENT OF PROBLEM: Manufacturers of several intraoral scanners have recommended a 2-step strategy for scanning the edentulous mandible. The 2-step technique requires scanning one side first and then moving to the other side. However, whether inconsistency in stitching occurs that results in loss of accuracy or distortion is unclear. PURPOSE: The purpose of this clinical study was to measure the potential distortion of intraoral scans of edentulous mandibular arches made with a 2-step scanning strategy and to assess their differences with conventional impressions. MATERIAL AND METHODS: Twenty mandibular edentulous arches were scanned by 1 investigator with an intraoral scanner using a 2-step scanning strategy, and a corresponding polysulfide conventional impression was obtained. The conventional impression was then immediately scanned with the same intraoral scanner. The obtained standard tessellation language (STL) files were superimposed with a surface-matching software program. After a preliminary alignment, the STL meshes were trimmed and reoriented; then, the final alignment was carried out and meshes moved to a metrology software program where their mean distance was measured. In addition, a surface curve (SIOS) was traced on the intraoral scan from the right to left retromolar pad along the residual ridge and automatically projected onto to the conventional impression scan to obtain a new curve (SC). The mean distance between SIOS and SC was measured and recorded as an indicator of the distortion by considering the X-, Y-, and Z-axes and the overall 3-dimensional (3D) deviation. The analysis was performed for the full curve length and after dividing it into 6 regions of interest. Univariate and multivariate statistical analyses were used to investigate the significance of the extent of the mean 3D distance, as well as the effects of measurement positions (side and region) between and within patients on differences along the X-, Y-, and Z-axes (α=.05). RESULTS: The mean (-0.08 mm; standard error: 0.025) 3D distance between the intraoral scan and conventional impression was significantly different from zero (P=.003). No significant effect of the factor "side" was found by using generalized estimated equation models for the X-, Y-, and Z-axes, and global 3D deviations between SIOS and SC (P>.05), which appeared to exclude distortion. Conversely, a significant effect was found for the factor "region" (P<.05), with no significant differences (P>.05) between corresponding regions on the 2 sides. CONCLUSIONS: Intraoral scans of the edentulous mandibular arch made in a 2-step procedure did not exhibit significant distortion in comparison with conventional impressions.

Effect of Fabrication Technology on the Accuracy of Surgical Guides for Dental-Implant Surgery.

BACKGROUND: The accuracy of surgical guides is a relevant factor in both surgical safety and prosthetic implications. The impact of widespread fabrication technologies (milling and 3D printing) was investigated. METHODS: Surgical guides manufactured by means of two specific milling and 3D-printing systems were digitized and compared in a 3D analysis with the digital file of the designed guides. The surface mean 3D distance (at the surface where the teeth and mucosa made contact) and the axial and linear deviations of the sleeves' housings were measured by means of a metrological software program. Univariate and multivariate statistical analyses were used to investigate the effects of the fabrication technology, type of support, and arch type on the surgical guides' accuracy. RESULTS: The median deviations of the intaglio surface in contact with the mucosa were significantly (p < 0.001) lower for the milled surgical guides (0.05 mm) than for the 3D-printed guides (-0.07 mm), in comparison with the reference STL file. The generalized estimated equation models showed that the axial deviations of the sleeves' housings (a median of 0.82 degrees for the milling, and 1.37 degrees for the 3D printing) were significantly affected by the fabrication technology (p = 0.011) (the milling exhibited better results), the type of support (p < 0.001), and the combined effect of the fabrication technology and the sleeve-to-crest angle (p = 0.003). The linear deviation (medians of 0.12 mm for the milling and 0.21 mm for the 3D printing) of their center points was significantly affected by the type of support (p = 0.001), with the milling performing slightly better than the 3D printing. CONCLUSIONS: The magnitude of the difference might account for a limited clinical significance.

Effect of implant angulation and patrice on the retention of overdenture attachment systems: An in vitro study.

PURPOSE: To test the retention of two different overdenture attachment matrices and straight abutments when implants are placed at 0-, 15-, and 30-degree diverging angulations as well as the retention of 15-degree-angled abutments to correct the overall angulation to 0-degrees. MATERIALS AND METHODS: Matching aluminum blocks were machined to incorporate two dental implants at 0-degree, 15-degree, and 30-degree relative angulations and overdenture attachments to simulate a two-implant overdenture. At 0-degree, 15-degree, and 30-degree implant angulation, straight abutments were studied. At 30-degree implant angulation, an additional group was compared utilizing 15-degree angulated abutments that corrected the overall implant angulation to 0-degrees. A custom-designed testing apparatus that allowed automated insertion and removal of the simulated overdenture was designed, with three independent testing stations, each consisting of one simulated arch and one simulated overdenture base. The baseline and residual retention forces after 30,000 dislodging cycles of the simulated overdenture were measured. One-way ANOVA was used to compare retention differences among different color patrices within the 0-, 15-, and 30-degree implant angulation groups followed by Tukey's multiple comparison test. Two sample t-tests were used to compare 0-degree versus 15-degree implant groups with straight abutments and 30-degree implant groups with straight abutments versus 30-degree implant groups with angulated abutments. RESULTS: Regardless of implant angulation or abutment correction, the change in retention exhibited by the Novaloc system after testing was not statistically significant for all patrice types (p > 0.05); however, the change in retention exhibited by the Locator system was statistically significant for the tested group (p = 0.0272). In both the Novaloc and Locator systems, the baseline and final retention values provided by the different patrices were significantly different except for the white and green Novaloc patrices in the 15-degree divergent implant group which did not meet the specified level of significance (p = 0.0776). CONCLUSION: Within the limitations of this study, implant angulations upto 15 degrees do not affect differential change in retention of Novaloc patrices. There is no difference between Novaloc white inserts (light retention value) and green inserts (strong retention values) when implants diverge upto 15 degrees. When Novaloc straight abutments were placed on implants diverging by 30 degrees, blue extra-strong retention inserts outperformed yellow medium retention inserts by maintaining a higher retention value after 30,000 cycles. When utilizing Novaloc 15-degree angulated abutments that correct the overall implant angulation to zero degrees, the red light retentive patrice provides steady retention. Finally, the Locator-green patrice system provides greater retention than the comparable Novaloc-blue patrice combination; however, it also loses more retention after 30,000 cycles.

Oral lichen planus in children: An Italian case series.

Oral lichen planus usually occurs in adults; there are no clear data regarding the incidence and the clinical features of oral lichen planus in children. This paper reports clinical findings, treatments, and outcomes of 13 Italian patients with oral lichen planus in childhood diagnosed between 2001 and 2021. The most common finding was keratotic lesions with reticular or papular/plaque-like patterns, confined to the tongue in seven patients. Although oral lichen planus in childhood is rare and the malignant transformation index is unknown, specialists must be aware of its characteristics and oral mucosal lesions must be correctly diagnosed and managed.

Cost/effectiveness analysis of treatment options for the rehabilitation of the total edentulous mandible.

BACKGROUND: Several solutions are available for the rehabilitation of edentulous jaws. Each treatment option is characterised by specific advantages and drawbacks. OBJECTIVE: The aim of this research was to perform a cost-effectiveness (CE) analysis of the main rehabilitative solutions of totally edentulous mandibles. METHODS: Decision tree models were built using TreeAge Pro Healthcare 2021 software to compare the following strategies: Conventional Denture (CD), Overdenture retained by two implants (OD-2), Overdenture retained by a bar on two implants (ODbar), Overdenture retained by 4 mini-implants (ODmini) and Fixed denture supported by 4 implants (FD). Costs were estimated using data from public rate tables. Effectiveness measures were obtained from a meta-analysis of literature data, normalising the different scales in 0-1 range. A value of 30 000€ per 1 normalised utility points was set as threshold of willingness to pay (WTP). Probabilistic sensitivity analysis (PSA) with 1000 Monte Carlo Simulations was performed to characterise uncertainty. RESULTS: Total costs ranged between 1804,40€ for CD and 10 008,80€ for FD rehabilitations, with an effectiveness of 0,69 and 0,95 normalised points (0-1 scale) for the two solutions. The ODbar resulted to be the most CE strategy at the established WTP value, with the highest Net Monetary Benefit (22 001,20€), followed by the OD-2 rehabilitation (21 866,80€). PSA analysis confirmed the dominance of OD-2 and ODbar strategies, confirming a net separation from the other alternatives. CONCLUSION: OD stabilised by 2 implants could represent a good rehabilitative solution for patients with edentulous mandible, being a good trade-off in terms of costs and effectiveness. Nevertheless, a standardised measure of oral health-related quality of life is needed to obtain more reliable results.

Cast-free fabrication of a digital removable partial denture with a polyetheretherketone framework.

Digital workflows for removable partial dentures have enabled new machinable framework materials, including polyetheretherketone (PEEK). In addition, all denture components can be designed and manufactured digitally. Nonetheless, physical casts are still required for assembly of the components. The adoption of a cast-free fabrication procedure may enhance benefits, including a reduced number of procedures, faster processing, and reduced material waste. The purpose of this technical report was to demonstrate a workflow for the fabrication of a removable partial denture with a PEEK framework, milled teeth, and milled flanges, which uses intraoral scanning and no physical casts.

Accuracy of trial complete dentures fabricated by using fused deposition modeling 3-dimensional printing: An in vitro study.

STATEMENT OF PROBLEM: Three-dimensional (3D) printing technologies commonly used for trial complete dentures use photopolymerizing resins. Although effective, some clinical, process-related, and practical issues associated with them are still unclear. The option of using alternative printing technologies may help in overcoming limitations. PURPOSE: The purpose of this in vitro study was to evaluate the trueness of trial dentures fabricated by using 3D-printing fused deposition modeling (FDM). MATERIAL AND METHODS: Ten maxillary and 10 mandibular digital complete trial dentures designed from intraoral scans were fabricated from polylactic acid by using a FDM 3D-printer. Each denture was scanned, and the scans were compared with the digital file of the designed denture by means of a surface-matching software program. The mean distance (both signed and absolute) was measured and recorded for the intaglio surface, as well as for the entire denture surface. Statistical analysis was performed to investigate the significance of the extent of measured distances, as well as differences between intaglio and global deviations; subgroup analysis for arch type was also performed (α=.05). RESULTS: Mean values of the intaglio distance were not significantly different from zero (P=.223). The manufacturing accuracy of the intaglio surface was higher than that measured for the entire denture (P<.001), confirmed both by the averaged signed (0 mm and -0.028 mm, respectively) and the absolute mean deviations (0.06 mm and 0.08 mm, respectively). No significant differences were found between maxillary and mandibular trial dentures. CONCLUSIONS: 3D-printing may constitute a valid and practical option for accurate and affordable digital trial dentures.

Insertion and removal torque of dental implants placed using different drilling protocols: An experimental study on artificial bone substitutes.

PURPOSE: The aim of this in vitro study was to measure the insertion and removal torque values of dental implant replicas inserted into artificial bone blocks using different surgical burs and drilling protocols. MATERIALS AND METHODS: Four types of artificial, polyurethane bone blocks were used with different thicknesses (1 and 2 mm) and densities (soft-1 mm, soft-2 mm, dense-1 mm, and dense-2 mm) of the simulated cortical and cancellous bone, respectively. Each bone construct was drilled with Straumann and Densah drills in both clockwise and counterclockwise directions for a total of 16 experimental conditions. For every scenario, 38 implant replicas were inserted and then removed after 1 min. Outcomes of interest were the insertion and removal torque values which were recorded by a torque meter. ANOVA and Tukey HSD tests were used to assess differences across each combination of drill, direction, and bone type. RESULTS: Densah counterclockwise registered statistically greater values for both insertion and removal torque, followed by Densah clockwise, Straumann counterclockwise, and Straumann clockwise. Increasing insertion and removal torque values were progressively reported for bone type (soft-1 mm, dense-1 mm, soft-2 mm, and dense-2 mm). The mean values of insertion and removal torque were significantly different (p < 0.05) across the four bone types, different burs, and with the two drilling modalities. CONCLUSIONS: Densah bur resulted in significantly greater values of torque compared to the Straumann drills for all the experimental conditions. The thickness of the cortical layer and the counterclockwise drilling direction play a significant role in determining the implant insertion torque.

Intaglio surface trueness of milled and 3D-printed digital maxillary and mandibular dentures: A clinical study.

STATEMENT OF PROBLEM: While the dimensional accuracy of the intaglio surface of a removable complete denture is key to its adaptation, comfort, and clinical performance, information on the ability of milling and 3D-printing workflows to accurately reproduce this surface is lacking. PURPOSE: The purpose of this clinical study was to compare the trueness of the intaglio surface of milled and 3D-printed removable complete digital dentures. MATERIAL AND METHODS: Intraoral scans were obtained from 14 participants for a total of 20 edentulous arches. Ten maxillary and 10 mandibular denture bases were then designed and fabricated with a completely digital workflow, both with milling and 3D-printing. Fabricated dentures were digitized with the same intraoral scanner used to obtain intraoral digital scans of the edentulous arches. Standard tessellation language (STL) files of the printed and milled denture bases were used for 3D analysis and comparisons with the STL file of the corresponding designed denture base. Specifically, a reverse engineering software program was used to trim and extract intaglio surfaces, align them, and measure their global mean 3D distance. In order to evaluate the homogeneity of production accuracy of each manufacturing process, the intaglio surfaces were also divided into several regions of interest and the corresponding 3D distances measured. Within- and between-group differences and maxillary and mandibular dentures differences were assessed with parametric and nonparametric tests (α=.05). RESULTS: Milling showed a global better trueness of the entire intaglio surface (-0.002 mm) than 3D-printing (0.018 mm), both for the whole data set (P<.001) and for maxillary (P=.032) or mandibular (P=.049) denture base subgroups. Within each fabrication technology, maxillary (P<.11) and mandibular dentures (P=.2) showed no significant difference in trueness. Measured deviations were significantly different from zero for the 3D-printed dentures (P<.001), but not for the milled dentures (P=.487). Additionally, for milled dentures, no significant difference in trueness was found among the 11 regions of interest identified for the maxillary dentures (P=.085) and the 13 regions of interest for the mandibular dentures (P=.211). Conversely, 3D-printing showed significant variations in trueness among the same zones of interest, both in maxillary (P<.001) and mandibular (P=.004) dentures. CONCLUSIONS: Within the limits of the manufacturing methodologies used for complete dentures, milling can provide a slightly better trueness of the intaglio surface than 3D-printing, with less variation across several zones of interest. However, given the magnitude of such differences, they may be reasonably considered to be of limited, if any, clinical significance.

Assessment of tooth displacement during the cast-free digital processing of milled dentures.

STATEMENT OF PROBLEM: Denture tooth displacement may have a significant impact on denture occlusion. This aspect has seldom been investigated, especially for digital denture processing techniques. PURPOSE: The purpose of this clinical study was to evaluate the accuracy of tooth position with milled digital dentures processed without physical casts. MATERIAL AND METHODS: Ten maxillary and 10 mandibular dentures designed from intraoral scans, milled, and processed without physical casts were investigated. The standard tessellation language (STL) files of the digitally designed dentures were compared with the scan of the dentures after processing (milling the denture base, milling teeth in a complete arch, and then bonding teeth into the base). The STL files were superimposed by using a surface-matching software program. After a preliminary alignment, the STL meshes were trimmed and reoriented; then, the final alignment was carried out by using the cameo surface. Six reference points (the mesiobuccal cusp on the most distal molar, the canine cusp, the middle of the incisal edge of the central incisor on both the left and the right side) were selected to measure tooth displacements along the X-, Y-, and Z-axes, corresponding (from the preliminary reorientation) to anteroposterior, mediolateral, and occlusal displacement, respectively. Tooth position accuracy was assessed by using median and interquartile range values. Univariate and multivariate statistical analyses were used to investigate the significance of the extent of displacements, as well as differences among displacement directions, reference teeth, side, and denture arch type (α=.05). RESULTS: Only the median (0.2 mm; interquartile range: 0.27 mm) occlusal displacement was significantly different from zero. A generalized estimated equation model addressing occlusal displacement as a dependent variable showed no significant effect of tooth type, side, or denture arch type, either alone or in combination. CONCLUSIONS: The tooth position of both maxillary and mandibular milled digital dentures processed without physical casts was accurate in the anteroposterior and mediolateral directions. Occlusal displacement seemed to be within the range of clinical acceptability; its consistency throughout the arch allowed optimization or compensation at the design or manufacturing step.

Three Dimensional Printed Surgical Guides: Effect of Time on Dimensional Stability.

PURPOSE: To analyze, in vitro, the dimensional stability over time of 3D-printed surgical guides. MATERIALS AND METHODS: Ten surgical guides, manufactured by digital light processing 3D-printing technology, were scanned immediately after post-processing and then after 5, 10, 15, and 20 days. The corresponding standard tessellation language (STL) files were used for comparison with the reference CAD project. Mean absolute deviation (MAD) of the intaglio surface, axial, and linear deviations of the sleeves' housings were measured. Generalized estimated equations models (α = 0.05) were used to investigate the effect of time. RESULTS: MAD of the teeth intaglio surface showed less variation (minimum: 0.002, maximum: 0.014 mm) than that of the mucosa (minimum: 0.026, maximum: 0.074 mm). Axial variations of the sleeves' housings on the sagittal (minimum: -0.008°, maximum: -0.577°) and frontal plane (minimum: -0.193°, maximum: 0.525°) changed with similar patterns, but opposite trends (decreasing for the former). Linear deviations of center points of the sleeves' housings had a shifting (minimum: -0.074, maximum: 0.02 mm) pattern with a decreasing tendency. Time after processing had a significant effect, either alone or nested with guides volume, on all outcomes of interest, except for MAD of the mucosa intaglio surface (p < 0.001), which was significantly affected only by the time-volume nested effect (p = 0.012). CONCLUSIONS: Within the limitations of the experimental design, postmanufacturing dimensional variations of surgical guides were statistically significant. Although limited, they are an additional source of variability affecting the overall accuracy of computer-guided surgery. As such, they should be addressed by further research.

Surgical guides for dental implants: Measurement of the accuracy using a freeware metrology software program.

PURPOSE: Manufacturing-related inaccuracies of surgical guides for static computer-aided implant surgery may contribute to the overall potential error in the obtained implant position. Measuring such inaccuracies before surgery may provide quality control assessment and improve the safety and outcomes of guided implant surgery. This technical report demonstrates a workflow to measure the accuracy of a surgical guide (at the intaglio surface and sleeve housing) using a freeware metrology software program. METHODS: The scan of a milled surgical guide was aligned to and compared with its reference computer-aided design model using a freeware metrology software program (GOM Inspect suite; GOM GmbH). The trueness of the internal surface of the surgical guide was measured as an indicator of adaptation to the supporting tissues. Additionally, some features were constructed to extract the plane at the sleeve entrance and sleeve axis and to set a local coordinate system on them. Linear and angular deviations between the planned and obtained sleeve axes were measured using this system. Such measurements, together with additional known data (sleeve offset and the planned implant length), allowed the estimation of linear errors in implant position at both the implant platform and apex by applying common geometric formulas, based on the assumption that all other sources of error in implant position could be effectively controlled during the surgical procedure. CONCLUSIONS: The proposed digital technique is a cost-effective approach for quality control of the inaccuracies of a surgical guide and predicts the related potential error in implant position.

Effects of postpolymerization conditions on the physical properties, cytotoxicity, and dimensional accuracy of a 3D-printed dental restorative material.

STATEMENT OF PROBLEM: Although the introduction of high-speed 3-dimensional (3D) printing technology has significantly reduced printing time, the time required for postpolymerization is a speed-determining step because of the long wait time. How postpolymerization conditions affect material properties is unclear. PURPOSE: The purpose of this in vitro study was to assess the physical properties, accuracy, and biosafety of a 3D-printed dental restorative material according to postpolymerization conditions. MATERIAL AND METHODS: Specimens were prepared by 3D printing with a digital light processing 3D printer with 1 interim dental material (C&B MFH). All printed specimens underwent a postpolymerization process with 5 different postpolymerization devices and were designated as groups D1 (D102H), FO (Form Cure), LC (LC-3DPrintBox), ME (Medusa), and MP (MP100). The light intensity and temperature of each device were measured, and the Vickers hardness, flexural strength and modulus, degree of conversion (DC), cytotoxicity, and polymerization shrinkage were analyzed. Statistical analyses were conducted with 1-way analysis of variance, the Tukey post hoc test, and regression testing (α=.05). Scanning electron microscopy was used to assess the fracture surface characteristics of the specimens. RESULTS: Light intensity was strongest with the ME device, and the temperature inside the device during postpolymerization showed the highest increase with the LC device and the lowest increase with the D1 device. The LC group specimens showed the highest mean Vickers hardness, and the MP group showed the lowest. The flexural strength was ≥100 MPa in all groups, with a flexural modulus ranging from 1.17 to 1.5 GPa. The DC results were similar to the physical properties test results. The D1, FO, LC, and ME groups all showed ≥70% cell viability, indicating no toxicity. The FO group showed the highest shrinkage rate of 0.52%. CONCLUSIONS: When the light intensity was strong, the surface was sufficiently hard, and toxic substances were not eluted even after a short postpolymerization time, suggesting that light intensity modulation and time management can be used to improve the postpolymerization process.

The Multilayer GBR Technique: An Alternative Approach for One-Stage Transmucosal Implant Placement in the Presence of Horizontal Defects. A Case Series.

This study presents a one-stage technique for horizontal guided bone regeneration and transmucosal implant placement in the presence of hard and soft tissue defects. The proposed technique uses autologous bone particles, deproteinized bovine bone matrix, collagen membranes, and concentrated growth factor membranes to create a multilayer barrier and enhance tissue regeneration. Four patients were treated with a total of seven implants. Digital analyses of intraoral scan data taken at baseline and at 6 months postsurgery showed a mean increase in tissue volume of 157.4 mm3. The patient satisfaction was high, and no complications were observed.

Comparative cost-analysis for removable complete dentures fabricated with conventional, partial, and complete digital workflows.

STATEMENT OF PROBLEM: Comparative cost-analysis related to different manufacturing workflows for removable complete denture fabrication is seldom performed before the adoption of a new technology. PURPOSE: The purpose of this study was to compare the clinical and laboratory costs of removable complete dentures fabricated with a conventional (workflow C), a partial digital (workflow M), and a complete digital (workflow D) workflow and to calculate the break-even points for the implementation of digital technologies in complete denture fabrication. MATERIAL AND METHODS: Clinical and laboratory costs for each of the investigated workflows and the manufacturing options related to denture base and denture teeth fabrication were collected from 10 private Italian dental laboratories and clinics. The selected variables included the clinical and laboratory manufacturing time needed to complete each workflow (opportunity cost); costs for materials, labor, packaging, and shipping; and capital and fixed costs for software and hardware, including maintenance fees. The effect of manufacturing workflows and their options on the outcomes of interest was investigated by using generalized estimated equations models (α=.05). Cost minimization and sensitivity analysis were also performed, and break-even points were calculated for the equipment capital costs related to the implementation of workflows M and D. RESULTS: From a laboratory standpoint, workflows M and D and related manufacturing options significantly (P<.001) reduced manufacturing time (5.90 to 6.95 hours and 6.30 to 7.35 hours, respectively), and therefore the opportunity cost of each denture compared with workflow C. Workflow M allowed variable costs savings between 81 and 169 USD, while workflow D allowed for an additional saving of 34 USD. The sensitivity analysis showed that the break-even point related to the capital investment for the equipment needed to implement workflows M and D could be reached, depending on the manufacturing options adopted, between 170 and 933 dentures for workflow M and between 73 and 534 dentures for workflow D. From a clinical standpoint, workflows C and M were almost identical. Conversely, workflow D, which included intraoral scanning, required 1 fewer appointment, saving 0.6 hours of chairside time and about 14 USD for materials compared with M. CONCLUSIONS: Digital workflows (partial and complete digital workflows) were more efficient and cost-effective than the conventional method of fabricating removable complete dentures, with workflow D showing the lowest opportunity and variable costs and break-even point. Savings increased when stock denture teeth were replaced with milled denture teeth and still further with the adoption of 3-dimensionally (3D) printed denture teeth. Milling equipment and materials for denture base fabrication were more expensive than those for 3D-printing. Milling monobloc dentures reduced opportunity and labor costs but increased material cost.

Added effect of 1% topical alendronate in intra-bony and inter-radicular defects as part of step II periodontal therapy: a systematic review with meta-analysis and trial sequential analysis.

BACKGROUND: This systematic review and meta-analysis aimed to investigate the role of alendronate combined with step 2 of periodontal therapy in reducing probing pocket depth, improving clinical attachment level, and reducing bone defect depth in intra-bony and inter-radicular defects. METHODS: RCTs with more than 6 months follow-up were included in this study. Risk of bias assessment was performed using the Cochrane collaboration tool. In addition, meta-analysis and trial sequential analysis were used to aggregate the available evidence. RESULTS: Seven studies met the inclusion criteria and were included in the systematic review. Topical application of alendronate during second step of periodontal therapy significantly improved PD and CAL. CONCLUSION: Local application of alendronate may confer a beneficial effect when applied during step II of periodontal therapy even if long term studies are needed to confirm these results. CLINICAL RELEVANCE: Considering the emerging role of host-inflammatory response in treatment of periodontitis and the antiresorptive and osteostimulative properties of bisphosphonates, several studies are focusing on the role of alendronate as an addition to non-surgical periodontal therapy.

Removable Partial Dentures with Polyetheretherketone Framework: The Influence on Residual Ridge Stability.

PURPOSE: To provide, in a clinical case-control study, 1-year data on edentulous residual ridge dimensional changes for patients wearing removable partial dentures (RPD) with Polyetheretherketone (PEEK) framework, fabricated with a digital workflow, and a control group of untreated patients. MATERIALS AND METHODS: Ten patients were treated with PEEK RPD, and six controls were studied. Intraoral scans at baseline (T0) and after a median period of 1 year (T1) were superimposed, trimmed, and reoriented (T0r and T1r), moved to a metrology software, and realigned. A curve (C0) was then traced on T0r, along the residual ridge crest; its projection (C1) on T1r was obtained. The mean distance C0-C1 was the dependent variable of interest and represented the 1-year changes in the height of the edentulous ridge. In addition, mean 3D distance between T0 and T1 at each edentulous area was measured. Differences in these outcomes measured between RPD treated and control groups were statistically assessed. RESULTS: Twenty-six and 14 edentulous areas were investigated in the RPD treated and control groups, respectively. No significant differences were observed for potentially confounding variables, such as median follow-up time (12.5 vs. 13 months, respectively), the alignment accuracy between T0r and T1r (0.01 mm vs. 0 mm, respectively), the median number of remaining teeth (6 vs. 8.5, respectively), and the median length of edentulous areas (25.5 mm vs. 22.8 mm, respectively). For the outcomes of interest, no statistically significant difference was seen in the mean distance between C0 and C1 (i.e., changes in residual ridge height: -0.39 ± 0.52 mm vs. -0.52 ± 0.54 mm, respectively) or in the mean 3D distance at corresponding points of the denture bearing areas (-0.3 ± 0.46 mm vs. -0.4 ± 0.35, respectively). CONCLUSIONS: Although 1 year is a relatively short observation period, this clinical study shows that there are no short-term differences in edentulous residual ridge height and overall dimensions between patients wearing PEEK RPD, fabricated with a digital workflow, and controls without an RPD.