Comparison of Four Different Dental Implant Removal Techniques in Terms of the Weight and Volume of Bone Loss.

PURPOSE: Several approaches have been suggested for implant removal. However, further research is necessary to review data regarding the amount of bone removed and the duration of removal time for different procedures. This study evaluates and compares various implant removal techniques.  Materials and methods: A polyurethane block was scanned to create an implant surgical guide. Afterward, implant-guided surgery was performed on 60 simulated bone blocks. The implants were then separated into four groups and removed utilizing the counter-torque ratchet, trephine drills, burs, and piezosurgery. RESULTS: For the weight of bone loss, there were significant differences in the median between the counter-torque ratchet technique (CTRT) and trephine (p < 0.01), CTRT and bur (p < 0.01), trephine and piezo (p < 0.01), and bur and piezo (p = 0.04). All groups, except CTRT and the piezo group, demonstrated a statistically significant difference (p < 0.01) in the procedure durations. Regarding the volume of bone loss, a statistically significant difference (p < 0.01) was found between each group.  Conclusions: CTRT showed the least amount of bone loss. On the other hand, the trephine technique was demonstrated to be the fastest. It is essential to consider the limitations and risks when choosing the approach for implant removal.

Accuracy of 3D printed scan bodies for dental implants using two additive manufacturing systems: An in vitro study.

This study compared the accuracy of implant scan bodies printed using stereolithography (SLA) and digital light processing (DLP) technologies to the control (manufacturer's scan body) Scan bodies were printed using SLA (n = 10) and DLP (n = 10) methods. Ten manufacturer's scan bodies were used as control. The scan body was placed onto a simulated 3D printed cast with a single implant placed. An implant fixture mount was used as standard. The implant positions were scanned using a laboratory scanner with the fixture mounts, manufacturer's scan bodies, and the printed scan bodies. The scans of each scan body was then superimposed onto the referenced fixture mount. The 3D angulation and linear deviations were measured. The angulation and linear deviations were 1.24±0.22° and 0.20±0.05 mm; 2.63±0.82° and 0.34±0.11 mm; 1.79±0.19° and 0.32±0.03 mm; for the control, SLA, and DLP, respectively. There were statistical differences (ANOVA) among the three groups in the angular (p<0.01) or linear deviations (p<0.01). Box plotting, 95% confidence interval and F-test suggested the higher variations of precision in the SLA group compared to DLP and control groups. Scan bodies printed in-office have lower accuracy compared to the manufacturer's scan bodies. The current technology for 3D printing of implant scan bodies needs trueness and precision improvements.

Influence of Metal Guide Sleeves on the Accuracy and Precision of Dental Implant Placement Using Guided Implant Surgery: An In Vitro Study.

PURPOSE: Metal sleeves are commonly used in implant guides for guided surgery. Cost and sleeve specification limit the applications. This in vitro study examined the differences in the implant position deviations produced by a digitally designed surgical guide with no metal sleeve in comparison to a conventional one with a metal sleeve. MATERIALS AND METHODS: The experiment was conducted in two steps for each step: n = 20 casts total, 10 casts each group; Step 1 to examine one guide from each group with ten implant placements in a dental cast, and Step 2 to examine one guide to one cast. Implant placement was performed using a guided surgical protocol. Postoperative cone-beam computed tomography images were made and were superimposed onto the treatment-planning images. The implant horizontal and angulation deviations from the planned position were measured and analyzed using t-test and F-test (p = 0.05). RESULTS: For Step 1 and 2, respectively, implant deviations for the surgical guide with sleeve were -0.3 ±0.17 mm and 0.15 ±0.23 mm mesially, 0.60 ±1.69 mm, and -1.50 ±0.99 mm buccolingual at the apex, 0.20 ±0.47 mm and -0.60 ±0.27 mm buccolingual at the cervical, and 2.73° ±4.80° and -1.49° ±2.91° in the buccolingual angulation. For Step 1 and 2, respectively, the implant deviations for the surgical guide without sleeve were -0.17 ±0.14 mm and -0.06 ±0.07 mm mesially, 0.35 ±1.04 mm and -1.619 ±1.03 mm buccolingual at the apex, 0.10 ±0.27 mm and -0.62 ±0.27 mm buccolingual at the cervical, and 1.73° ±3.66° and -1.64° ±2.26° in the buccolingual angulation. No statistically significant differences were found in any group except for mesial deviation of the Step 2 group (F-test, p < 0.001). CONCLUSIONS: A digitally designed surgical guide with no metal sleeve demonstrates similar accuracy but higher precision compared to a surgical guide with a metal sleeve. Metal sleeves may not be required for guided surgery.

Influence of the Residual Ridge Widths and Implant Thread Designs on Implant Positioning Using Static Implant Guided Surgery.

PURPOSE: Aggressive implant macrothread designs have been widely used. However, the effects of the aggressive thread design on the accuracy of static guided surgery, especially in a case of narrow residual ridge, have not been well-studied. The aim of this study was to evaluate the effects of two different implant macrothread designs and the residual ridge widths on the accuracy of tooth-supported static guided implant surgery. MATERIALS AND METHODS: Forty implant fixtures with two different macrodesigns: a conventional thread design bone level tapered (BLT), and an aggressive thread design bone level tapered (BLX) were placed in 40 simulated polyurethane models with narrow and wide residual ridges. The placed implant positions were compared with the planned implant position and angulational deviation, as well as three-dimensional (3D) deviations at the entry and apex of the implant were measured. One-way ANOVA with Tukey's multiple comparisons (ɑ = 0.05) were used to determine level of significance between the mean and variance deviation values. 95% confidence intervals and box plots were used to demonstrate the means and ranges of precision. RESULTS: In terms of angulational deviation, there was no statistically significant difference in the mean deviations for both types of implants, p = 1.55 and p = 0.84 for wide and narrow ridge groups, respectively. However, the range of deviation was much larger in the narrow ridge of the BLX group compared to the BLT group. In both narrow ridge and wide ridge, the BLX group had lower mean 3D deviation values at both the entry and the apex with statistically significant differences for both entry point of the wide ridge (p = 0.027) and narrow ridge (p = 0.022) as well as at the apex of the wide ridge (p = 0.006) but not the apex of the narrow ridge (p = 0.142). CONCLUSION: The aggressive larger thread design of dental implants may influence the accuracy of implant placement more than the ridge dimension.

Influence of implant diameter on accuracy of static implant guided surgery: An in vitro study.

STATEMENT OF PROBLEM: Static guided implant surgery may be the most accurate method of implant placement to date. However, within the same guided implant system, whether accuracy is affected when placing a larger diameter implant that requires more drills than a smaller diameter implant is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the influence of implant diameter on the angulation and 3-dimensional (3D) deviations of posterior single implant placement using static guided surgery. MATERIAL AND METHODS: A polyurethane dental cast was made with an edentulous site at the maxillary right first molar position. Identical implant planning for each of 3 dental implant diameters 3.3, 4.1, and 4.8 mm (Straumann BLT) were made, and surgical guides for each implant diameters were fabricated by stereolithography. Fifteen implants of each diameter (N=45) were placed in simulated casts. A scan body was placed and the cast was scanned using an intraoral scanner. The positional discrepancies of implant placement, including angulation as well as 3D implant cervical and apex area deviations, were compared with the planned position. Linear ANOVA single factor analysis (ɑ=.05) was used, and box plots were made. RESULTS: The ranges of angulation deviations for 3.3-, 4.1-, and 4.8-mm implants were 3.6 degrees to 6.0 degrees, 3.7 degrees to 7.7 degrees, and 3.1 degrees to 6.7 degrees, respectively. The ranges of 3D implant entry deviations of 3.3-, 4.1-, and 4.8-mm implants were 0.96 to 1.4, 0.85 to 1.72, and 0.89 to 1.78 mm, respectively. The ranges of 3D implant apex of 3.3-, 4.1-, and 4.8-mm implants were 0.63 to 1.21, 0.64 to 1.48, and 0.48 to 1.27 mm, respectively. No statistically significant differences were found in any of the 3 measurements: P=.67 for deviation in angulation; P=.27 for 3D implant deviation of entry; and P=.3 for 3D implant deviation of the apex. CONCLUSIONS: Implant diameters had no significant effect on placement deviations when a single posterior static guided surgery was used.

Salivary biomarkers associated with obstructive sleep apnea: a systematic review.

Introduction: This study aimed to define and characterize current literature describing salivary biomarker changes with the goal of improving diagnosis and treatment outcomes for sleep apnea.Area Covered: A search of six databases yielded 401 peer-reviewed articles published through October 2019 corresponded to 221 unique references following deduplication. Twenty studies were selected. The sample size ranged from 17 to 99. The samples were mostly whole saliva and selected glandular areas.Expert Opinion: Most targeted studies focused on the level of salivary cortisol and ɑ-amylase. One study used RNA transcriptome analysis of 96 genes. Only two explored novel targets using mass spectrometry. ɑ-amylase, myeloperoxidase, and IL-6 were among those biomarkers found associated with OSA. Cytokeratin, CystatinB, calgranulin A, and alpha-2-HS-glycoprotein are upregulated in OSA patients based on non-targeting mass spectrometry. Salivary cortisol and ɑ-amylase and others appeared to be associated with severity of OSA and OSA treatment. There were inconsistencies in saliva collection and processing protocols. More studies are needed in exploring novel biomarkers to examine if these biomarkers are capable of diagnosing and monitoring OSA through proteomics or transcriptomics. Salivary biomarkers have a potential to be a noninvasive measure for the disease diagnosis and treatment outcome monitoring for sleep apnea.

Effects of two Postprocessing Methods onto Surface Dimension of in-Office Fabricated Stereolithographic Implant Surgical Guides.

PURPOSE: To evaluate the effects of two postprocessing methods in terms of the overall, intaglio, and cameo surface dimensions of in-office stereolithographic fabricated implant surgical guides. MATERIALS AND METHODS: Twenty identical implant surgical guides were fabricated using a stereolithographic printer. Ten guides were postprocessed using an automated method. The other ten guides were postprocessed using a series of hand washing in combination with ultrasonics. Each guide was then scanned using cone-beam computed tomography to produce a set of digital imaging and communications in medicine (DICOM) files which were converted into standard tessellation language (STL) files. The STL file was then superimposed onto the original STL design file using the best fit alignment. The average positive and negative surface discrepancy differences in terms of means and variances were analyzed using t-test (α = 0.05). RESULTS: For the alternative group, the average positive and negative overall, intaglio, and cameo surface discrepancies were 77.38 ± 10.68 µm and -67.74 ± 6.55 µm; 78.83 ± 8.65 µm and -68.16 ± 5.26 µm; and 70.5 ± 8.48 µm -64.84 ± 5.55 µm, respectively. For the automated group, the average positive and negative overall, intaglio, and cameo surface discrepancies were 51.88 ± 4.38 µm and -170.7 ± 11.49 µm; 64.3 ± 4.44 µm and -89.45 ± 6.25 µm; and 83.59 ± 4.81 µm and -144.26 ± 13.19 µm, respectively. There was a statistical difference between the means of the two methods for the overall, intaglio, and cameo positive and negative discrepancies (p < 0.001). CONCLUSIONS: For a single implant tooth-supported implant guide, using hand washing with ultrasonics appeared to be consistently better than the automated method. The manual method presented with more positive discrepancies, while the automated method presented with more negative discrepancies.

Accuracy of Implant Placement Position Using Nondental Open-Source Software: An In Vitro Study.

PURPOSE: To evaluate the accuracy of implant placement position using two different dental implant planning software. MATERIALS AND METHODS: A set of Digital Imaging and Communications in Medicine (DICOM) files from a cone beam computed tomography of a patient missing maxillary right first premolar was used. Implant planning was done using two open-source programs: A nondental 3D Slicer/Blender (3DSB) software and a commercial dental implant treatment planning program: Blue Sky Plan 4 (BSP4). An intraoral scan of the same patient was used to create a standard tessellation language (STL) file of the maxillary arch and later printed into 20 identical casts. Ten surgical guides were printed for each group as well. A dental implant (3.8 mm × 12 mm, Biohorizons) was placed into each cast using fully guided surgical protocol. The horizontal displacements at the implant cervical platform and at the implant apex as well as the angulation displacements were measured using digital scanning of the implant scan bodies and were analyzed using a 3D compare software. Statistical analyses were conducted (⍺ = 0.05) using t-test and F-test to examine differences in trueness and precision, respectively. RESULTS: The average horizontal deviations for the platform and the apex, respectively, were 0.33 ± 0.12 mm and 0.76 ± 0.30 mm for 3DSB and 0.44 ± 0.21 mm and 0.98 ± 0.48 mm for BSP4. The average angulation deviations for 3DSB and BSB4 were 2.34 ± 0.93° and 3.07 ± 1.57°, respectively. There were no statistical differences in the means (t-test) of the platform, apex, and angulation deviations (p = 0.16, p = 0.19, and p = 0.18, respectively). There were statistical differences in the variances (F test) of the platform (p = 0.043) and angulation (p = 0.049) deviations but not the apex (p = 0.059) deviations. CONCLUSIONS: The combination of nondental open-source software, 3D Slicer/Blender can be used to plan implant guided surgery with an accuracy similar to commercial dental software with slightly higher precision. Open-source nondental software can be considered as an alternative in dental implant treatment planning and guided surgery.

Intaglio Surface Dimension and Guide Tube Deviations of Implant Surgical Guides Influenced by Printing Layer Thickness and Angulation Setting.

PURPOSE: To measure overall intaglio dimensional and tube deviations of implant guides printed at 50 and 100 µm layer thickness at 0°, 45°, and 90° angulation using a stereolithographic (SLA) printer. MATERIALS AND METHODS: A surgical implant guide design from a subject missing a maxillary right central incisor, used as the original standard tessellation language (STL) were stereolithographically fabricated at each thickness and angulation, 50 and 100 µm layer thickness at 0°, 45°, and 90° angulation (n = 10 each group). The guide was then scanned using cone beam computed tomography. The digital imaging and communications in medicine (DICOM) scanned files were then converted to an STL format. The overall dimensional deviations of the intaglio surface and the positioning of the implant guide tube were then superimposed onto the original designed STL file using best-fitting alignment. A t-test and an F-test as well as ANOVA followed by a post hoc t-test were used to determine statistical significant differences (α = 0.05) for the intaglio surface and guide tube deviation, respectively. RESULTS: The overall intaglio surface discrepancies (µm) printed at 0°, 45°, and 90° were 55.07 ± 1.36, 52.39 ± 2.09, and 61.02 ± 15.96 for 50 µm layer; and 98.38 ± 10.55, 84.47 ± 10.61, and 90.26 ± 5 for 100 µm layer with statistically significant differences for both t-test and F-test, p < 0.001. The maximal guide tube linear deviations (µm) printed at 0°, 45°, and 90° were 10.78 ± 3.84, 8.16 ± 3.68, and 12.57 ± 5.39 for 50 µm layer (ANOVA, p = 0.096); and 10.95 ± 5.23, 16.79 ± 4.97, and 22.63 ± 2.81 for 100 µm layer (ANOVA, p < 0.001). The maximal guide tube angular deviations (°) printed at 0°, 45°, and 90° were 1.29 ± 0.30, 0.64 ± 0.13, and 0.56 ± 0.21 for 50 µm layer (ANOVA, p < 0.001); and 1.57 ± 0.29, 0.86 ± 0.14, and 1.02 ± 0.31 for 100 µm layer (ANOVA, p = 0.034). There was a statistical difference in the deviations between 50 and 100 µm layer printing in all printed angulations except at 0° (t-test, p = 0.05, p = 0.03, and p = 0.001 for 0°, 45°, and 90°) and linear deviations (t-test, p < 0.001, p = 0.009, and p = 0.001 for 0°, 45°, and 90°). CONCLUSION: Printing at 50 µm layer reduces dimensional intaglio deviations in general and reduces tube angular deviations with different angulations of printing. However, the deviations were only ∼60 to 100 µm for the intaglio dimension deviations; and ∼0.04 to 0.26 mm and ∼0.25° to ∼2° for tube deviations.

Accuracy and precision of 3D-printed implant surgical guides with different implant systems: An in vitro study.

STATEMENT OF PROBLEM: Implant guided surgery systems promise implant placement accuracy and precision beyond straightforward nonguided surgery. Recently introduced in-office stereolithography systems allow clinicians to produce implant surgical guides themselves. However, different implant designs and osteotomy preparation protocols may produce accuracy and precision differences among the different implant systems. PURPOSE: The purpose of this in vitro study was to measure the accuracy and precision of 3 implant systems, Tapered Internal implant system (BioHorizons) (BH), NobelReplace Conical (Nobel Biocare) (NB), and Tapered Screw-Vent (Zimmer Biomet) (ZB) when in-office fabricated surgical guides were used. MATERIAL AND METHODS: A cone beam computed tomography (CBCT) data set of an unidentified patient missing a maxillary right central incisor and intraoral scans of the same patient were used as a model. A software program (3Shape Implant Studio) was used to plan the implant treatment with the 3 implant systems. Three implant surgical guides were fabricated by using a 3D printer (Form 2), and 30 casts were printed. A total of 10 implants for each system were placed in the dental casts by using the manufacturer's recommended guided surgery protocols. After implant placement, postoperative CBCT images were made. The CBCT cast and implant images were superimposed onto the treatment-planning image. The implant positions, mesiodistal, labiopalatal, and vertical, as well as implant angulations were measured in the labiolingual and mesiodistal planes. The displacements from the planning in each dimension were recorded. ANOVA with the Tukey adjusted post hoc pairwise comparisons were used to examine the accuracy and precision of the 3 implant systems (α=.05). RESULTS: The overall implant displacements were -0.02 ±0.13 mm mesially (M), 0.07 ±0.14 mm distally (D), 0.43 ±0.57 mm labially (L), and 1.26 ±0.80 mm palatally (P); 1.20 ±3.01 mm vertically in the mesiodistal dimension (VMD); 0.69 ±2.03 mm vertically in the labiopalatal dimension (VLP); 1.69 ±1.02 degrees in mesiodistal angulation (AMD); and 1.56 ±0.92 degrees in labiopalatal angulation (ALP). Statistically significant differences (ANOVA) were found in M (P=.026), P (P=.001), VMD (P=.009), AMD (P=.001), and ALP (P=.001). ZB showed the most displacements in the M and vertical dimensions and the least displacements in the P angulation (P<.05), suggesting statistically significant differences among the M, VMD, VLP, AMD, and ALP. NB had the most M variation. ZB had the least P deviation. NB had the fewest vertical dimension variations but the most angulation variations. CONCLUSIONS: Dimensional and angulation displacements of guided implant systems by in-office 3D-printed fabrication were within clinically acceptable limits: <0.1 mm in M-D, 0.5 to 1 mm in L-P, and 1 to 2 degrees in angulation. However, the vertical displacement can be as much as 2 to 3 mm. Different implant guided surgery systems have strengths and weaknesses as revealed in the dimensional and angulation implant displacements.

Exploring training dental implant placement using computer-guided implant navigation system for predoctoral students: A pilot study.

INTRODUCTION: Recent computer-guided dynamic navigation systems promise a novel training approach for implant surgery. This study aimed to examine learning progress in placement of dental implants among dental students using dynamic navigation on a simulation model. MATERIALS AND METHODS: Senior students with no implant placement experience were randomly assigned five implant placement attempts involving either three maxillary or four mandibular implants distributed in the anterior/posterior, and left/right segments. Implant placement was planned using a Navident Dynamic Guidance system. Surgical time was recorded. Horizontal, vertical and angulation discrepancies between the planned and placed implant positions were measured using superimposed CBCT scans. Data were analysed with repeated measures regression with Tukey's adjusted pairwise comparisons (α = 0.05). RESULTS: Fourteen students participated, with a mean age of 26.1 years and equal males and females. Mean time for implant placement was associated with attempt number (P < 0.001), implant site (P = 0.010) and marginally related to gender (P = 0.061). Students had a significant reduction in time from their first attempt to their second (10.6 vs 7.6 minutes; adjusted P < 0.001) then plateaued. Overall 3D angulation (P < 0.001) and 2D vertical apex deviation (P = 0.014) improved with each attempt, but changes in lateral 2D (P = 0.513) and overall 3D apex deviations (P = 0.784) were not statistically significant. Implant sites were associated with lateral 2D, 2D vertical and overall 3D apex deviation (P < 0.001). DISCUSSION: Males were marginally faster than females, had slightly lower overall 3D angulation, and reported higher proficiency with video games. Novice operators improved significantly in speed and angulation deviation within the first three attempts of placing implants using dynamic navigation. CONCLUSION: Computer-aided dynamic implant navigation systems can improve implant surgical training in novice population.

Differential Mucosal Gene Expression Patterns in Candida-Associated, Chronic Oral Denture Stomatitis.

PURPOSE: Denture stomatitis is a common condition manifested by inflammation of the oral mucous membrane beneath a denture. The objective of this study was to compare the transcriptome of human palatal mucosa with chronic oral stomatitis-associated Candida albicans infection to that of healthy oral mucosa. MATERIALS AND METHODS: Oral palatal biopsies were obtained from 17 healthy and 15 C. albicans-infected stomatitis subjects for whole transcriptome analyses. The presence of C. albicans was confirmed by cytology and cultivable methods. The clinical severity of the stomatitis was evaluated by the Newton Classification (Class II or III). For transcriptome analyses a false discovery rate (FDR) of <0.05 was used, and the effects of age, race, and gender were evaluated by principle component analysis (PCA). Specific differentially expressed genes identified by mRNA array data were confirmed by measurements of salivary protein expression using multiplex analyses. RESULTS: Microarray analysis of mRNA expression indicated that in C. albicans stomatitis there were 3034 genes-in-play that were differentially expressed and met the FDR < 0.05 criteria. Two hundred thirty five (235) genes were up-regulated >2-fold, and 71 genes were down-regulated >2-fold. Five of the 6 most significant gene ontology pathways involve inflammation and activation of the immune response with CD28 and CTLA signaling of T cells. There was strong up-regulation of TLR2, CD14, MYD88, IKKA, and NFKB as the dominant toll-like receptor-signaling pathway. The expression of several extracellularly expressed inflammatory protein genes was up-regulated in candidiasis, and 2 were confirmed as up-regulated within the saliva using protein multiplexing analyses. CONCLUSIONS: Neutrophil recruitment and activation, epithelial suppression, and T-cell activation appear as major pathways in chronic oral candidiasis. Tissue up-regulation of TLR2 pathways, as well as potential C. albicans binding proteins, was observed, whereas keratin and adhesion molecule synthesis were down-regulated. Several candidate biomarkers to potentially identify the presence of oral candidiasis were differentially expressed in tissues and saliva.

Trephination-based, guided surgical implant placement: A clinical study.

STATEMENT OF PROBLEM: Conventional guided implant surgery promises clinical success through implant placement accuracy; however, it requires multiple drills along with surgical sleeves and sleeve adapters for the horizontal and vertical control of osteotomy drills. This results in cumbersome surgery, problems with patients having limited mouth opening, and restriction to specific drill or implant manufacturers. A protocol for using trephination drills to simplify guided surgery and accommodate multiple implant systems is introduced. PURPOSE: The purpose of this clinical study was to evaluate the accuracy of implant placement using this novel guided trephine drill protocol with and without a surgical sleeve. MATERIAL AND METHODS: Intraoral scanning and preoperative cone beam computed tomography (CBCT) scans were used for implant treatment planning. Surgical guides were fabricated using stereolithography. Implant surgery was performed using the guided trephination protocol with and without a surgical sleeve. Postoperative CBCT scans were used to measure the implant placement deviations rather than the implant planning position. Surgical placement time and patient satisfaction were also documented. One-tailed t test and F-test (P=.01) were used to determine statistical significance. RESULTS: Thirty-five implants in 17 participants were included in this study. With a surgical sleeve, implant positional deviations were 0.51 ±0.13 mm vertically, 0.32 ±0.10 mm facially, 0.11 ±0.11 mm lingually, and 0.38 ±0.13 mm mesially. Without a surgical sleeve, implant positional deviations were 0.58 ±0.27 mm vertically, 0.3 ±0.14 mm facially, 0.39 ±0.16 mm lingually, and 0.41 ±0.12 mm mesially. No statistically significant difference was found between the 2 protocols (P>.01), except that the sleeve group had greater vertical control precision (F-test, P=.006), reduced placement time, and the time variation was reduced (t test, P=.003; F-test, P<.001). CONCLUSIONS: This trephination-based, guided implant surgery protocol produces accurate surgical guides that permit guided surgery in limited vertical access and with the same guided surgery protocol for multiple implant systems. Guided sleeves, although not always necessary, improve depth control and reduce surgical time in implant placement.

Do Implant Surgical Guides Allow an Adequate Zone of Keratinized Tissue for Flapless Surgery?

PURPOSE: A major advantage of guided implant surgery using 3-dimensionally printed guides is the ability to perform accurate flapless surgery. A drawback of a flapless technique is the inability to manipulate soft tissue to ensure sufficient gingiva around the implant. The purpose of this study was to determine how often flapless surgery using surgical guides results in less than 2 mm of keratinized tissue surrounding the implant. MATERIALS AND METHODS: This retrospective analysis included 27 maxillary and 27 mandibular implant sites that underwent treatment planning for implant-guided surgery using 3Shape Implant Studio (3Shape, Copenhagen, Denmark). Intraoral scan images were used to measure the width of the keratinized tissue on the buccal aspect of each implant site in both arches and the lingual aspect in the mandibular arch. Three examiners measured the amount of buccal and lingual keratinized tissue in millimeters at each implant site. Analysis of variance (P < .05) and correlation coefficients were used to determine statistically significant differences in keratinized tissue among sites. RESULTS: No statistically significant difference was found either between the widths of buccal keratinized tissue in the maxillary anterior (4.06 ± 1.42 mm) and posterior (4.93 ± 2.54 mm) areas (P = .293) or between the amounts of buccal and lingual keratinized tissue in the mandible (P = .995). The keratinized tissue width in the maxillary buccal area was significantly different (4.48 ± 2.04 mm) from that in the mandibular posterior buccal (1.98 ± 1.41 mm) and lingual (1.98 ± 1.23 mm) areas (P < .001). Over 77% of maxillary implant sites had greater than 3 mm of gingiva, and just over 20% had sufficient gingiva in the mandible. CONCLUSIONS: Adequate keratinized tissue was found in most of the planned maxillary implant sites, whereas most of the mandibular posterior implant sites had inadequate keratinized tissue. Therefore, elevation of a flap to preserve and reposition existing keratinized tissue around implants should be considered when planning to use tooth-borne surgical guides in the posterior mandible.

Computer-guided implant removal: A clinical report.

Occasionally, osseointegrated dental implants must be removed because of complications such as malpositioning or screw fracture. This is most often accomplished with a surgical handpiece and trephine. However, a flap is often required to access and visualize the implants. This paper presents a treatment in which computer planning and a 3-dimensional-printed, custom fabricated, surgical guide was used to assist in implant removal. This technique simplified the procedure, allowed conservative removal of peri-implant bone, and permitted subsequent immediate implant replacement.

In Vivo Tooth-Supported Implant Surgical Guides Fabricated With Desktop Stereolithographic Printers: Fully Guided Surgery Is More Accurate Than Partially Guided Surgery.

PURPOSE: Desktop stereolithographic printers combined with intraoral scanning and implant planning software promise precise and cost-effective guided implant surgery. The purpose of the present study was to determine the overall range of accuracy of tooth-supported guided implant surgery using desktop printed stereolithographic guides. MATERIALS AND METHODS: A cross-sectional study comparing fully and partially guided implant surgery was conducted. Preoperative cone beam computed tomography (CBCT) and intraoral scans were used to plan the implant sites. Surgical guides were then fabricated using a desktop stereolithographic 3-dimensional printer. Postoperative CBCT was used to evaluate the accuracy of placement. Deviations from the planned positions were used as the primary outcome variables. The planning software used, implant systems, and anterior/posterior positions were the secondary outcome variables. The differences between the planned and actual implant positions in the mesial, distal, buccal, and lingual dimensions and buccolingual angulations were determined, and the accuracy was compared statistically using the 1-tail F-test (P = .01), box plots, and 95% confidence intervals for the mean. RESULTS: Sixteen partially edentulous patients requiring placement of 31 implants were included in the present study. The implant deviations from the planned positions for mesial, distal, buccal, and lingual dimensions and buccolingual angulations with the fully guided protocol (n = 20) were 0.17 ± 0.78 mm, 0.44 ± 0.78 mm, 0.23 ± 1.08 mm, -0.22 ± 1.44 mm, and -0.32° ± 2.36°, respectively. The corresponding implant deviations for the partially guided protocol (n = 11) were 0.33 ± 1.38 mm, -0.03 ± 1.59 mm, 0.62 ± 1.15 mm, -0.27 ± 1.61 mm, and 0.59° ± 6.83°. The difference between the variances for fully and partially guided surgery for the distal and angulation dimensions was statistically significant (P = .006 and P < .001, respectively). No statistically significant difference was found between the software programs. Anterior implants had less variation in deviation than posterior implants. CONCLUSIONS: Fully guided implant surgery is more accurate than partially guided implant surgery. Implant positional deviation is influenced by implant location but not implant systems or software. If possible, clinicians should use guided surgery protocols that allow placement of implants through a surgical guide.

How Accurate Are Implant Surgical Guides Produced With Desktop Stereolithographic 3-Dimentional Printers?

PURPOSE: The use of tooth-supported static stereolithographic guides has greatly improved the ability to ideally place implants. This study was designed to determine the accuracy of in office-printed implant surgical guides. MATERIALS AND METHODS: Using 3shape Implant Studio, a treatment plan for implant placement for tooth 8 was developed using a digital intraoral scan from a Trios scanner and cone-beam computed tomography. Ten stereolithographic guides were printed using a Form2 3-dimensional printer. Pre- and post-implant insertion digital scans were used to determine distance and angulation differences in the mesiodistal and faciolingual positions of the implants compared with the planned position. RESULTS: The mean difference in mesiodistal direction at the alveolar crest between planned implants and placed implants was 0.28 mm (range, 0.05 to 0.62 mm) and the difference in the faciolingual direction was 0.49 mm (range, 0.08 to 0.72 mm). The mean mesiodistal angulation deviation was 0.84° (range, 0.08° to 4.48°) and the mean faciolingual angulation deviation was 3.37° (range, 1.12° to 6.43°). CONCLUSIONS: In-office fabricated stereolithographic implant surgical guides show similar accuracy to laboratory- or manufacturer-prepared guides. This technique provides a convenient and cost-effective means of assuring proper implant placement.

Dental and orofacial mesenchymal stem cells in craniofacial regeneration: The prosthodontist's point of view.

Of the available regenerative treatment options, craniofacial tissue regeneration using mesenchymal stem cells (MSCs) shows promise. The ability of stem cells to produce multiple specialized cell types along with their extensive distribution in many adult tissues have made them an attractive target for applications in tissue engineering. MSCs reside in a wide spectrum of postnatal tissue types and have been successfully isolated from orofacial tissues. These dental- or orofacial-derived MSCs possess self-renewal and multilineage differentiation capacities. The craniofacial system is composed of complex hard and soft tissues derived from sophisticated processes starting with embryonic development. Because of the complexity of the craniofacial tissues, the application of stem cells presents challenges in terms of the size, shape, and form of the engineered structures, the specialized final developed cells, and the modulation of timely blood supply while limiting inflammatory and immunological responses. The cell delivery vehicle has an important role in the in vivo performance of stem cells and could dictate the success of the regenerative therapy. Among the available hydrogel biomaterials for cell encapsulation, alginate-based hydrogels have shown promising results in biomedical applications. Alginate scaffolds encapsulating MSCs can provide a suitable microenvironment for cell viability and differentiation for tissue regeneration applications. This review aims to summarize current applications of dental-derived stem cell therapy and highlight the use of alginate-based hydrogels for applications in craniofacial tissue engineering.

Common Polymorphisms in IFI16 and AIM2 Genes Are Associated With Periodontal Disease.

BACKGROUND: The single nucleotide polymorphism (SNP) context of a previously identified periodontitis-associated locus is investigated, and its association with microbial, biologic, and periodontal disease clinical parameters is examined. METHODS: A 200-kb spanning region of 1q12 previously highlighted in a genome-wide association scan among 4,766 European American individuals (SNP rs1633266) was annotated. Two haplotype blocks were selected. Association of these polymorphisms with data on microbial plaque composition, gingival crevicular fluid (GCF)-interleukin (IL)-1ß levels, and clinical parameters of periodontal disease were examined. Descriptive analysis of IFI16 and AIM2 protein expression in gingival tissues from healthy individuals (n = 2) and individuals with chronic periodontitis (n = 2) was done via immunohistochemistry. RESULTS: The highlighted locus is a 100-kb region containing the interferon γ-inducible protein 16 (IFI16) and absent in melanoma 2 (AIM2) genes. Two haplotype blocks, rs6940 and rs1057028, were significantly associated with increased extent bleeding on probing and levels of microorganisms Porphyromonas gingivalis, Tannerella forsythia, and Campylobacter rectus (P ≤0.05). Haplotype block rs1057028 was also significantly associated with pathogens Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, increased GCF-IL-1ß levels, and extent of probing depth ≥4 mm (P ≤0.05). Prevalence of severe periodontitis (biofilm-gingival interface P3 classification) was positively associated with haplotype block rs1057028. Similar trends were observed for haplotype block rs1057028. IFI16 and AIM2 protein expression was observed in multiple cell types of gingival tissues, including inflammatory cells. CONCLUSION: This study found IFI16 and AIM2 SNPs associated with higher levels of periodontal microorganisms and an increased percentage of periodontal disease clinical parameters, suggesting the need for functional studies and additional fine-mapping of variants in the 1q12-locus.

In-office fabrication of dental implant surgical guides using desktop stereolithographic printing and implant treatment planning software: A clinical report.

Guided surgery is accepted as the most accurate way to place an implant and predictably relate the implant to its definitive prosthesis, although few clinicians use it. However, recent developments in high-quality desktop 3-dimensional stereolithographic printers have led to the in-office fabrication of stereolithographic surgical guides at reduced cost. This clinical report demonstrates a protocol for using a cost-effective, in-office rapid prototyping technique to fabricate a surgical guide for dental implant placement.