The International Journal of Oral & Maxillofacial Implants, 05/2020

Purpose: To evaluate the influence on healing of the bony window elevated inward in the sinus cavity as a cortical bone graft. Materials and Methods: Eighteen rabbits were included in the experiment. At the test sites (bony window), the antrostomy was prepared and the remaining bony window was elevated together with the sinus mucosa. At the control sites, the bony window was gently detached before the sinus mucosa elevation and discarded. The space obtained was grafted with deproteinized bovine bone mineral (DBBM). A collagen membrane was positioned on the antrostomy at both sides. The rabbits were euthanized after 2, 4, and 8 weeks in groups of six each. Histologic analyses in different regions of the elevated space were carried out, and a Wilcoxon test was used to estimate differences. Microcomputed tomography (microCT) analyses were also performed. Results: After 2 weeks of healing, higher proportions of new bone were found in the test group compared with the control group due to the higher amount of bone formed in the region subjacent to the sinus mucosa. In this region, higher amounts of new bone were also found in the test group after 4 (P = .028) and 8 weeks of healing (P = .345). After 8 weeks of healing, the percentage of new bone was higher at the control sites compared with the test sites, with the proportions being 25.4% ± 3.2% and 21.3% ± 6.1%, respectively. In this period of evaluation, the bony window contributed with 20.1% ± 5.3% of vital bone in the test group. A fraction of 60.4% ± 10.8% of its surface was surrounded by new bone. In the microCT analysis, after 8 weeks of healing, fractions of 22.3% ± 1.6% and 22.2% ± 0.7% of bone were found in the test and control groups, respectively. Conclusion: The presence of the bony window positively influenced the healing in the elevated space, especially in the submucosa region. The bony window was vital and incorporated into newly formed bone. Keywords: animal study, bone healing, collagen membrane, morphometry, sinus floor elevation, xenograft

Purpose: The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments. Materials and Methods: Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments. Results: The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment. Conclusion: Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species. Keywords: abutments, biofilms, dental implant, microbiology, prosthetic, surfaces, titanium, zirconia

Purpose: Citation-based metrics, such as the H-classics method, have been used as an indicator to assess academic performance in the scientific community. However, information addressing issues regarding self-citation, citation halflife, and subject area of origin in implant dentistry is lacking. The purpose of this study was to investigate the citation characteristics of H-classics articles in implant dentistry throughout different time periods. Materials and Methods: H-classics implant dentistry articles were searched and selected by applying the H-classics method from the Scopus database. Bibliometric analysis was conducted to evaluate the citation characteristics, including institutional and journal self-citation, citation half-life, and subject area of origin of identified H-classics articles. Results: The International Journal of Oral & Maxillofacial Implants and Clinical Oral Implants Research are the leading journals contributing the majority of citations to the retrieved H-classics articles. Articles published in the United States cited the most H-classics articles. Journal self-citation was 12.41% on average, while institutional self-citation was approximately 7.81%. Citation half-life decreased significantly across time periods, with an average decreasing ratio of 43.95%. Research on Scope III, bioengineering interventions, had the most prominent distribution citation frequency in the subject area "Others." Conclusion: This study provides insightful views regarding citation characteristics of H-classics articles in implant dentistry (eg, interdisciplinary publications on bioengineering interventions) during the investigation periods, which may foster the translation of preclinical research into clinical applications in the future. Keywords: bibliometrics, citation analysis, citation half-life, H-classics, implant dentistry, self-citation

Purpose: This study evaluated the bone-forming potential of the demineralized human dentin matrix by performing histologic and morphometric analyses. The immunolabeling of osteopontin, a determinant protein for bone repair, was also evaluated. Materials and Methods: Wistar rats were selected and submitted to the extraction of the right and left second molars. Tooth sockets were separated into two groups: the control group (right), which was filled with the blood clot, and the experimental group (left), which was filled with demineralized human dentin matrix. Animals were sacrificed at 5, 10, and 21 days. Histologic and histoquantitative analyses (analyses of variance [ANOVA] and Tukey's test) were performed, as well as immunostaining for osteopontin as an osteogenesis indicator. Results: After 5 days, demineralized human dentin matrix was incorporated by new trabeculae. After 10 days, connective tissue organization and new trabeculae were observed in the experimental group, and intense staining for osteopontin close to demineralized human dentin matrix was observed in the experimental group. After 21 days, the experimental group was showing mature trabeculae. A statistical difference was observed (P .05). There was a higher number of trabeculae in the experimental groups in all periods of analysis. The presence of osteopontin was observed more intensely at 10 days close to demineralized human dentin matrix. Conclusion: This study indicates that demineralized human dentin matrix implanted in tooth sockets induces the acceleration of osteogenesis. Keywords: bone repair, demineralized human dentin matrix, tooth sockets, osteopontin

Purpose: Compaction of particulated grafts is done manually; thus, the effect of compression force on bone regeneration remains unclear. The aim of this study was to evaluate the impact of two different compression forces on the consolidation of particulated bovine hydroxyapatite. Materials and Methods: Two titanium cylinders were fixed on the calvarium of eight New Zealand rabbits. Both defects were filled with particulated bovine hydroxyapatite subjected to a compression force of 0.7 kg/cm² or 1.6 kg/cm² before being covered with a resorbable collagen membrane. A handheld device that uses a spring to control the compression force applied by the plugger was used. At 6 weeks, histomorphometry of the area immediately adjacent to the calvaria bone and to the collagen membrane was performed. Results: It was shown that next to the calvaria, the bone volume per tissue volume (BV/TV) was 29.0% ± 8.8% and 27.6% ± 8.2% at low and high compression force, respectively; the bone-to-biomaterial contact (BBC) was 58.2% ± 25.0% and 69.3% ± 22.9%, respectively (P > .05). In the corresponding area next to the collagen membrane, BV/TV was 4.9% ± 5.1% and 5.7% ± 4.7%, and the BBC was 18.3% ± 20.8% and 20.1% ± 15.9%, respectively (P > .05). In addition, the number and area of blood vessels were not significantly affected by compression force. Conclusion: Both compression forces applied resulted in similar consolidation of bovine hydroxyapatite expressed by new bone formation and vascularization based on a rabbit calvaria augmentation model. Keywords: bone regeneration, compaction, compression force, particulated bone graft

Purpose: The purpose of this retrospective computed tomography study was to evaluate bone availability for dental implant placement, frequency of bone augmentation procedures, frequency of anatomical structures that compromise implant placement, and frequency of implant dimensions, and to determine which edentulous sites would benefit from the use of a sloped implant versus a traditional flat design. Materials and Methods: Recorded parameters included the width of the ridge, the buccal and lingual/palatal alveolar bone height in reference to different anatomical landmarks, determination of implant placement, selection of an implant with a flat or sloped top, and need for a secondary bone augmentation procedure. Results: One thousand three hundred seventy edentulous sites were evaluated in 216 patients. Implants could be placed in 60.6% of the total sites, where the coronal portion would be sloped in 59% of sites and conventionally flat in 41%; 39.4% of sites were not adequate for implant placement, where 56.5% needed additional guided bone regeneration procedures and 43.5% required sinus augmentation procedures. The inferior alveolar canal was the most frequent anatomical structure limiting size and/or placement. Conclusion: The study indicates that implants can be placed in slightly over half of edentulous sites without a secondary grafting procedure. The possibility of dental implant placement varied according to the volume and morphology of alveolar bone and related anatomical structures. This decreased from anterior to posterior in both arches. The sloped implant design was beneficial. In addition, the sloped implant design resulted in the placement of a longer implant. Keywords: bone regeneration, clinical research, CT imaging, diagnosis, epidemiology

Purpose: This study aimed to evaluate the effect of different surgical guide manufacturing techniques on the accuracy of the surgical guides produced prior to implant placement. Materials and Methods: Three type of guides were compared: milled guides using a commercial milling unit (C-Mill), printed guides using a commercial 3D printer (C-Print), and printed guides using a benchtop printer (B-Print). All the guides were fabricated on a single maxillary model for anterior implant and posterior implant placement. Ten guides were produced for each group. Four accuracy variables were measured: (1) internal accuracy, (2) vertical fit, (3) guide seating distortion, and (4) drilling access horizontal and vertical deviations. All the variables were virtually measured by 3D rendering software. The Kruskal-Wallis and the Mann-Whitney U tests were conducted to evaluate the significance of the differences among the guide groups. Results: The C-Mill guides were significantly more accurate than the other guide groups for all the accuracy variables (P .05). The C-Print group tended to show greater accuracy than the B-Print group, except for guide seating distortion and horizontal deviation of drilling access. However, a significant difference between the C-Print and B-Print groups was observed only for the vertical deviation of the posterior drilling access (P .05). The location of the implant seemed to have minimal influence on the drilling access accuracy, except for the vertical deviations of C-Mill and C-Print guides, where the anterior site was associated with significantly (P .05) greater errors than the posterior site. Conclusion: Producing guides by milling was more accurate and less vulnerable to seating distortion in comparison to printing. Despite the overall similarity between the two printers, the commercial printer tended to produce guides with greater accuracy than the benchtop printer. Keywords: 3D printing, additive manufacturing, distortion, drilling, milling

Purpose: This study investigated the effects of bisphosphonates, namely, alendronate and zoledronate, on the osteogenic activity of osteoprogenitor cells cultured on titanium surfaces at therapeutic doses in order to assess if altered osteoblastogenesis could compromise osseointegration and contribute to etiopathogenesis of painful disorders such as bisphosphonates-related osteonecrosis of the jaw (BRONJ) following implant placement. Materials and Methods: MC3T3-E1 Subclone 4 cells were utilized in this study. Therapeutic doses of alendronate and zoledronate were calculated based on reported peak plasma concentrations. The viability, proliferation, adhesion, and mineralization potential of cells was assessed using a LIVE/DEAD stain, alamarBlue assay, immunofluorescence microscopy, and Alizarin Red S staining, respectively. Results: Therapeutic doses of zoledronate negatively affected cell viability, whereas therapeutic doses of alendronate significantly enhanced cell differentiation and the amount of bone formation compared with the control. Conclusion: The findings of this study may provide some insight into the pathogenesis of BRONJ development following implant placement in patients treated with zoledronate and may have promising implications toward improved wound healing and osseointegration in patients treated with alendronate. Keywords: alendronate, bisphosphonates, dental implants, osseointegration, osteoblasts, zoledronate

Purpose: The aim of this study was to compare the effect of different surface treatments applied to short titanium and zirconia abutments on the bond strength of single-unit zirconia crowns. Materials and Methods: Sixty titanium abutments were shortened to 3 mm in length, fixed to analogs, and embedded in acrylic blocks. Three-dimensional views of abutments were obtained by scanning; then, zirconia abutments and copings were produced. The samples, which included titanium (n = 60) and zirconia (n = 60) abutments, were divided into five different groups (n = 12), and surface treatments were carried out; 1.5-W and 3-W Er,Cr:YSGG laser treatment, AL₂O₃ sandblasting, and tribochemical silica coating were applied to the groups, and the control group had no surface treatment. Copings were cemented to the samples with self-adhesive resin cement. The samples were then subjected to the pull-out test, and the results were processed via statistical analysis. Results: There was a significant difference between the titanium and zirconia groups (P .001). The mean bond strength values of the titanium samples were higher than those of the zirconia samples. The tribochemical silica coating gave a higher bond strength than the other treatments when applied to titanium abutments. For the zirconia abutments, the 1.5-W laser treatment, 3-W laser treatment, tribochemical silica coating, and Al₂O₃ sandblasting groups differed significantly from the control group; however, they were not significantly different from each other. Conclusion: The bond strength of zirconia crowns to short titanium and zirconia abutments increases with surface treatments. Furthermore, the surface treatments were more effective in increasing the bond strength for the titanium abutments than for the zirconia abutments. Keywords: dental, implant, retention, short abutment, titanium, zirconia

Purpose: To assess the effects of drilling protocol and bone density on the primary stability of implants with different macrogeometries currently used in clinical practice. Materials and Methods: This in vitro study compared the designs of two implants: Biomimetic Coral, a parallel-walled design with a slightly expanded platform and a symmetric progressive thread; and tapered Biomimetic Ocean, a reverse coronal design with an asymmetric progressive thread. The drilling alternatives were grouped according to the standard sequence for each type, plus an extra drill for hard bone, using laminated blocks with different densities. The insertion torques and implant stability quotient (ISQ) values were obtained with a surgical motor and resonance frequency analysis (RFA), respectively. Results: A total of 120 implants (n = 60 Ocean, n = 60 Coral) were inserted and analyzed without registering any deviation from the protocol. The Coral implants presented significantly higher insertion torque values (P .001), consistent with optimal osseointegration, for the standard drill, the dense bone drill, and the screw tap. Insertion torque was not affected by the drilling sequence (P = .124), and the effect of interaction between the implant design and drilling sequence was not significant (P = .940). Statistically significant differences were observed in insertion torque values due to the type of implant but not due to the bone density. The ISQ values were significantly higher (P .001) for the Coral design. In both the Ocean and Coral implants, ISQ was affected by the drilling sequence (P .001), as the ISQ values were higher in the standard sequence with screw tap drilling than in the standard sequence with a dense bone drill. A positive correlation was found between the insertion torque and ISQ values. Conclusion: The macrogeometry of the implant and the drilling sequence have a significant effect on both primary stability values (ISQ and insertion torque). The values for the Coral implant were statistically higher but still within the range required to achieve proper osseointegration. These results support the drilling sequence recommended by the manufacturer for this type of implant, using larger-diameter drills and screw taps in sites with harder or cortical bone. Keywords: dental implants, drilling sequence, implant stability quotient, insertion torque, macrogeometry, screw tap

Purpose: The aim of this study was to evaluate the clinical, esthetic, and patient-reported outcomes of one-piece zirconia implants placed in incisal areas using digital surgical templates after 1 year of follow-up. Materials and Methods: Patients who had lost an anterior tooth received a 3.3-mm-diameter zirconia implant placed by computer-guided surgery. Implant survival and soft tissue conditions were assessed periodically 1 week, 3 months, 6 months, and 1 year after loading. Standardized radiographs were taken at definitive prosthesis insertion and 1 year postloading to evaluate peri-implant bone loss. Additionally, the esthetic outcomes and patient-reported outcomes were also investigated. Results: Twenty zirconia implants were placed in 20 patients with no implants lost, resulting in 100% survival rates. A minor change in the mean marginal bone level (0.14 ± 0.87 mm) was found between definitive prosthetic loading and 12 months later. Periimplant soft tissue remained stable throughout the observation period. The mean Pink Esthetic Score and White Esthetic Score were 12.05 and 8.60, respectively, while the mean Gingival Papilla Index scores were 1.55 at the mesial papilla and 1.65 at the distal papilla at the 1-year follow-up. The mean visual analog scale scores for patient perception of the overall process, speech, mastication, and esthetics were 93.3 ± 7.8, 95.1 ± 5.3, 93.6 ± 7.6, and 94.5 ± 6.2 mm, respectively. Conclusion: For the 1-year results, 3.3-mm-diameter one-piece ceramic implants placed by computer-guided surgery showed favorable clinical performances with no failure when used for single-tooth replacement in anterior regions. Keywords: esthetic, guided surgery, survival, zirconia implants

Purpose: The aim of this retrospective clinical case series report was to evaluate the outcomes of patients who underwent zygomatic implant surgery with a recent technical modification of the extrasinus surgical protocol. Materials and Methods: The implant system presented in this study had a novel designed unthreaded body with a 12.5-mm sharp threaded apical end for obtaining maximum retention to the zygomatic bone. A total of 92 patients with severely atrophic maxillae were included in this study. All the patients were treated with a modification of the extrasinus protocol for insertion of 261 zygomatic implants. The mean follow-up of the patients was 34.5 ± 17.1 (SD) months (range: 6 to 72 months). The implant survival rate was the primary outcome. The intraoperative and postoperative complications were evaluated as additional criteria for success. Results: The cumulative implant survival rate was 97.99%. Definitive or provisional prostheses were delivered on the same day of surgery, which resulted in an improvement in the quality of life of the patients. Five implants failed in four patients. No sinusitis or mucositis was seen in any of the patients. Eleven postoperative complications occurred in seven patients. Conclusion: The novel zygomatic surgery protocol introduced in this study can be an effective alternative to augmentation procedures and conventional implants, especially in cases of extremely atrophic posterior maxillae. Keywords: atrophic maxilla, bone atrophy, dental implants, oral rehabilitation, zygomatic implants

Purpose: This investigation aimed to evaluate clinical, prosthetic, and patient-based outcomes of a milled bar with polyether ether ketone (PEEK) and metal housings for inclined implants supporting mandibular overdentures. Materials and Methods: Eighteen edentulous participants received four implants in the interforaminal area of the mandible (two vertically and two distally inclined), and implants were connected with milled bars. Overdentures were attached to the bars with PEEK female housing (test group). The control group consisted of participants who received milled bar overdentures with conventional metal housings but were case matched to the test group and served as a historical cohort. Clinical parameters (Plaque Index, Gingival Index, pocket depth, and bone loss) were measured at baseline, 6 months, and 12 months. Patient satisfaction (using visual analog scale) and prosthetic complications were recorded after 12 months. Results: The control group showed a significantly higher plaque score and marginal bone resorption compared with the test group. The test group showed higher satisfaction with retention, stability, speech, and esthetics compared with the control group (P .048). The test group showed a significantly lower incidence of female housing wear (P = .017), plastic clip wear (P .001), and plastic clip fracture/renewal (P = .049) than the control group. No difference between groups was noted for other clinical, prosthetic, and patient-based outcomes. Conclusion: PEEK housing of a milled bar may be a successful alternative to conventional metal housing for inclined implants supporting mandibular overdentures, as it is associated with favorable clinical, prosthetic, and patient-based outcomes after 1 year. Keywords: computer-guided surgery, flapless procedure, inclined implants, overdenture, prostheses, randomized controlled clinical trial

Purpose: The SAC Assessment Tool is a clinical decision support system based on the foundations of the SAC Classification System in Implant Dentistry developed by the International Team for Implantology in 2009. It objectively classifies a patient's rehabilitation with dental implants as straightforward, advanced, or complex, from both a surgical and restorative perspective. The aim of this research was to test the agreement between observers with different qualification levels and clinical experience when using this clinical decision support system as a method that mitigates risk. Materials and Methods: A total of 30 patients were randomly selected from clinical records, and diagnostic casts, intraoral and extraoral images, and panoramic radiographs were obtained. All data were analyzed with and without the SAC Assessment Tool by a dentist with advanced training and clinical experience in implant dentistry (control dentist) and compared with three colleagues (dentists 1, 2, and 3) with fewer qualifications and less clinical experience. All data were analyzed using statistical agreement tests (Fless kappa), interclass correlation, and agreement rate. The level of significance (α) was set at .05. Results: All patients included in this research presented 104 edentulous areas, which were subjected to surgical evaluation for possible placement of dental implants. Concerning the degree of risk evaluation for dental implant treatment, the results of this study found that the agreement rate of the control dentist without SAC and control dentist with SAC was excellent (81.7%); the agreement rate of the control dentist and dentists 1, 2, and 3 with the use of SAC was satisfactory (67.3% to 76.0%); the variable that presented a lower agreement rate (34.6%) was the comparison between dentists 1, 2, and 3 without use of the SAC Assessment Tool. Conclusion: The SAC classification seems to be a useful tool to assist dentists with less experience in implant dentistry with defining the complexity of the treatment and hence with patient selection. It helps in the collection and homogenization of important clinical data to assess the risk of implant-based rehabilitations, thus contributing to an increase in the agreement rate. Keywords: clinical decision support system, dental education, dental graduate, dental implants, educational

Purpose: To describe the prevalence of alveolar bone atrophy in edentulous arches of elderly individuals in relation to insertion of dental implants and the eventual need for bone grafting procedures. Materials and Methods: Computed tomography scan files of 228 edentulous arches of elderly patients (ages 65 to 100 years) were evaluated in relation to implant placement. Six measurements per arch were taken on cross-sectional reconstructions. Bone atrophy categories were described, in relation to implant placement, for the anterior and posterior sections of the arches. Six bone sections per arch were evaluated and allocated to the predetermined categories. Prevalence of each type of atrophy was calculated. Results: In the maxilla, only 5.0% of the patients showed a bone anatomy capable of receiving implants without any augmentation both in the posterior and anterior regions; 64.4% showed the need for major reconstruction in both areas. In the mandible, 17.3% of the patients did not require any augmentation in both regions; 9.4% were in need of major reconstruction in both areas. The anterior part of the arches could eventually be treated without any bone augmentation in 10.9% of the maxillae and 72.4% of the mandibles, while minor augmentation was needed in 16.8% of maxillae and 15.8% of mandibles. Conclusion: Most edentulous elderly patients show some degree of alveolar bone atrophy. It is often feasible to insert implants in the anterior mandible to support a restoration. In most maxillary cases, alveolar atrophy calls for augmentation procedures in both the anterior and posterior areas. In elderly individuals, the anterior maxilla often shows bone deficiency interfering with simple implant placement procedures, thus also limiting the use of tilted implants. Keywords: bone atrophy, dental implants, edentulous arches, elderly population

Purpose: To clinically and histomorphometrically compare a biphasic calcium phosphate (BCP) and deproteinized bovine bone mineral (DBBM) for sinus floor elevation. Materials and Methods: Sinus floor elevation procedures (lateral window) were performed randomly applying either BCP (test) or DBBM (control). At 6 months, bone biopsy specimens were harvested and dental implants were placed. The proportions of new bone, residual grafting material, and nonmineralized soft tissue were calculated. Four months after implant placement, the prosthetic reconstructions were inserted and the implant survival was assessed. Results: Fifty-one patients were treated; 25 were randomly allocated to the BCP group and 26 to the DBBM group. After 6 months in 50 patients, bone biopsy specimens could be harvested, and a total of 121 implants could be placed subsequently. The histomorphometric analysis revealed a comparable percentage of new bone in both groups (BCP 35.9%, DBBM 35.4%; P > .05). The remaining grafting material was significantly lower with BCP (25.3%) compared with DBBM (45.9%; P .001). Nonmineralized tissue was significantly higher for the BCP group (38.1%) compared with the DBBM group (18.2%; P .001). The implant survival rate at loading was assessed at the level of the patients (96.0% for BCP and 88.8% for DBBM; P > .05) and at the level of the implants (96.9% for BCP and 94.7% for DBBM; P > .05). Conclusion: Grafting with DBBM or BCP showed similar percentages of new bone 6 months after sinus floor elevation. Implant survival presented no significant difference until loading. Keywords: biphasic calcium phosphate, bone grafting, bone substitute, deproteinized bovine bone, histomorphometry, maxillary sinus, randomized controlled trial, sinus floor elevation

Purpose: The hydrophilic implant surface (INICELL) is a chemical alteration of a sandblasted and thermally acid-etched surface that should lead to long-term osseointegration. This study investigated 3-year results after early loading of implants with a hydrophilic, moderately rough surface in occlusal contact. Materials and Methods: This prospective case series study was conducted in subjects with partially edentulous mandibles. Implants were placed on day 21 and loaded with a provisional reconstruction after at least 21 days of healing (baseline, day 0) if their implant stability quotient (ISQ) was ≥ 70 (mean of three measurements) and were replaced by definitive porcelain-fused-to-metal prostheses at the 6-month follow-up visit. Follow-up examinations were planned 1, 3, 6, 12, and 36 months after baseline. Results: A total of 20 implants were placed in 15 patients (mean age: 51 years, range: 32 to 67 years). After 36 months, all implants were osseointegrated, and no suppuration was recorded. Small changes of bone level were observed between 3 months and 36 months. At 36 months, the median values of the 20 implants were 0.25 (range: 0 to 0.5, SD: 0.17), 0.25 (range: 0 to 1, SD: 0.27), and 4 (range: 2 to 7.25, SD: 1.17) for the mean modified Plaque Index (mPI), mean modified Sulcus Bleeding Index (mSBI), and mean probing pocket depth, respectively. The pairwise analysis between 3 and 36 months showed an improvement in the mean mPI (P = .0126) and mean mSBI (P = .0059). After 36 months, all patients (n = 15) were fully satisfied with a mean of 9.43 (range: 8 to 10, SD: 0.678) at the visual analog scale. Conclusion: Early functional loading of implants with a hydrophilic, moderately rough outer surface in occlusal contact 21 days after healing appears to be a safe and feasible treatment option when placed in the posterior mandible of partially edentulous patients. Keywords: delayed placement, dental implants, early loading, hydrophilic implant surface

Purpose: This 3-year study aimed to evaluate hard and soft tissue modification around a two-piece implant characterized by a transmucosal hyperbolic neck in healthy consecutive patients with a need for single-tooth replacement. Materials and Methods: Two-piece implants (n = 66) were placed with a flapless technique in 56 patients (27 men; 29 women; mean age 55 ± 9 years): 16 immediately after root extraction (immediate group), 20 after 8 to 12 weeks (early group), and 30 after 10 or more months (delayed group). The transmucosal hyperbolic neck was exposed 1 to 1.5 mm above gingival level. Customized abutments were positioned 3 months later with the implant-abutment connection located approximately 1 to 1.5 mm above soft tissue level. Provisional cemented resin crowns were designed with the finishing line at the hyperbolic neck and then positioned to avoid excessive compression of soft tissue, to guide gingival contours. Twenty days later, a definitive metal-ceramic crown was cemented. In all patients, the gingival biotype (thin or thick) was also evaluated. The primary outcomes were as follows: 36-month implant survival rate, peri-implant marginal bone level (MBL, in mm) changes observed in single-blind on radiographs at 1, 3, 6, 12, 24, and 36 months (T₁, T₃, T₆, T₁₂, T₂₄, and T₃₆), and pink esthetic score (PES) at T₆, T₁₂, and T₃₆ to analyze soft tissue adaptation after loading and crown application. The secondary outcomes were as follows: plaque score and bleeding on probing (BOP). Linear regression models and multilevel mixed logistic regression were used to detect any statistical difference of MBL according to operative parameters. Kruskal-Wallis one-way analysis of variance (ANOVA) on ranks was performed to assess statistical differences of PES at T₆, T₁₂, and T₃₆. Results: The survival rate was 100%. The dropout rate was 1.79%. No infections, mucositis, or peri-implantitis were reported. Implants placed in thick-biotype tissues showed a statistically different lower bone loss at 36 months with respect to the thin biotype (P .05). At 36 months, the early group showed lower bone loss compared with the delayed group (P .05). Multilevel mixed logistic regression revealed that gingival biotype was the parameter that was most related to MBL variations (P = .025). The PES value (mean ± SD) at T₆ was 10.76 ± 1.19 (median: 11; range: 8 to 13; IQR: 10 to 12). The values statistically increased at T₁₂ and T₃₆, where the mean values were 11.76 ± 1.10 (median: 12; range: 9 to 13; IQR: 11 to 12) and 11.83 ± 1.03 (median: 12; range: 9 to 14; IQR: 11 to 13). Conclusion: MBL and soft tissue clinical parameters measured around two-piece hyperbolic-neck implants were stable during the 3-year follow-up and free from complications. The exposure of the hyperbolic neck for 1.0 to 1.5 mm allowed a flapless one-stage surgery, which supported fast adaptation of the soft tissues, evidenced by high PES values and low percentages of BOP. The results from the study imply a new simple approach in the clinical management of gingival and bone tissue. Keywords: flapless procedure, hyperbolic neck, prospective cohort study, single implant, transmucosal placement

Purpose: This study examined a new 3D volumetric analysis method for the assessment of baseline-to-12-month changes of the soft tissue volume at early and immediately placed tapered implants after loading with ceramic single crowns. Materials and Methods: Eligible patients with one incisor, canine, or premolar to be extracted were included. The patients were divided randomly into early-placement or immediate-placement groups. Tapered implants (BLT, Institut Straumann) were placed after the extractions. In the early-placement group, the implants were placed 8 weeks after extraction. In the immediate-placement group, the implants were placed immediately after the extraction. All implants healed transmucosally, and the final crowns were inserted after healing (baseline). Impressions were made at screening, baseline, and 12 months after crown insertion (Permadyne, 3M). The casts were scanned (Imetric 4D) and aligned, and a superimposed area of interest (AOI) (labial/buccal aspects) was defined to assess the volumetric changes (GOM Inspect). Specific software (3Matic, Materialise NV) was used for volumetric analysis. The vertical mucosal recession was measured at each time point. Repeated-measures one-way analysis of variance and the Tukey method were used for statistical analysis (SPSS 22, IBM). Results: Twenty tapered implants (16 regular and four narrow) were placed in 20 patients (12 men and 8 women) in the early-placement (EP; n = 10) and immediate-placement (IP; n = 10) groups, respectively. Threedimensional volumetric analysis revealed soft tissue volume loss in both groups of 10.0 ± 16.5 mm3 (EP) and 24.3 ± 21.3 mm3 (IP) between baseline and 12 months (P = .6). The analysis also revealed local differences in the changes, displaying both localized gain and loss in both groups. Conclusion: With this novel 3D analysis method, true volumetric soft tissue differences, ie, both localized gain and loss, were specified between the treatment groups. Keywords: dental implants, early placement, immediate placement, soft tissue changes, volumetric analysis

Resorbable membranes are well described and employed for horizontal guided bone regeneration (GBR). However, the currently available literature does not provide information on the bone volumetric changes during the healing that follows GBR procedures and dental implant placement. Therefore, the aim of this pilot study was to initially analyze the volumetric bone changes after treating pristine edentulous mandibular defects with lateral GBR using freeze-dried bone allograft (FDBA) and collagen resorbable membrane. Six patients were selected for the analysis. Clinical changes in bone volume before and after GBR were measured. In addition, digital volumetric analysis of the augmented ridges was performed preoperatively, as well as 4 and 6 months after the GBR procedure. At the time of dental implant placement, bone cores were collected during the osteotomy for histologic analysis. Data on volume changes showed a mean of 297.5 ± 134 mm3 augmented bone volume at 4 months with 5% ± 3.78% resorption from 4 to ≥ 6 months. Histologic bone core analysis showed 44.9% ± 5.1% mineralization in the area of augmentation. Within the limitations of this pilot study, resorbable membranes exhibited reliability for GBR in intercalated mandibular defects, providing sufficient bone volume gain at ≥ 6 months for implant stabilization and limited resorption during graft healing. Keywords: 3D, bone graft, dental implants, guided bone regeneration, histomorphometry, volumetric

Guided dental implant surgery can optimize implant placement positioning, increase predictability, and decrease surgical invasiveness through flapless techniques. Static surgical guides have been used to accomplish this task, though limitations of patient opening and lack of coolant contact with the surgical site have been clinically significant weaknesses. Technologic advances have allowed robotically guided implant placement using haptic guidance. The absence of a static stereolithographic guide over the surgical area allows for optimal access and adequate cooling during osteotomies. The aim of this case series was to present the workflows of both static and robotic guidance in the same patient and measure deviations from the presurgical planning software to determine the practicability and accuracy of robotic guidance. Based on this case series, it can be concluded that using robotically assisted implant surgery can yield deviation results that are comparable to static CAD/CAM stereolithographic surgical guides. Robotic surgery can be performed predictably with minimal deviation in both simple and complex clinical situations. Further testing and analysis are needed to confirm this case study's results in a larger cohort of patients. Keywords: accuracy, dental implant, guided, robotic, static