The International Journal of Oral & Maxillofacial Implants, 04/2024

Purpose: To assess histologic and imaging outcomes related to new bone formation around implants, inserted simultaneously with sinus augmentation, and compare different types of grafts. Materials and Methods: This systematic review (SR) was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane Handbook for Systematic Reviews of Interventions. LILACS/BVS, MEDLINE/PubMed, Cochrane Library, and Embase databases, including gray literature and manual investigations, were searched to identify clinical trials reporting specific requirements. The present study needed human histologic and imaging data of bone formation around implants inserted into the maxillary sinus simultaneously with elevation and augmentation procedures. Study selection, risk of bias (Rob 2.0 or ROBINS-I), quality of evidence (GRADE), and data collection were performed by two independent reviewers. Results: Of the 1,101 potentially eligible articles, 44 were retrieved, 12 were assessed for eligibility, and 5 were included (4 randomized and 1 controlled clinical trial). As a result, 130 grafted sinuses with 179 placed implants in 103 patients were analyzed. The patients were aged between 24 and 79 years and followed up between 6 and 15 months. The heterogeneity between studies did not allow the data to be combined for meta-analysis. All graft materials proved to be viable options for the intervention. The use of biphasic calcium phosphate was related to higher bone-to-implant contact. Conclusions: All of the assessed grafts are viable options for the addressed intervention. The use of some material is justified to maintain the sinus volume and allow bone formation in the apical implant site under the sinus membrane. Longer chair time and donor site morbidity should be considered when choosing autogenous bone. Synthetic biphasic materials can be selected for this intervention due to superior bone-to-implant contact compared to deproteinized bovine bone.  Schlagwörter: maxillary sinus augmentation, simultaneous implant, graft materials, bone neoformation, systematic review

Purpose: To evaluate four decontamination strategies utilizing enzymatic agents available in most clinical settings to determine (1) the amount of biomaterial that can be removed in a group of previously used healing abutments (uHAs) and (2) the degree to which the decontaminated HAs are capable of inducing an inflammatory response in vitro compared to new HAs. Materials and Methods: In total, 50 HAs were collected following 2 to 4 weeks of intraoral use and distributed randomly into five test groups (groups A–E; n = 10 per group). Group A used enzymatic cleaner foam and an autoclave. Group B used an ultrasonic bath with enzymatic cleaner and an autoclave. Group C used a prophy jet, enzymatic cleaner foam, and an autoclave. Group D used a prophy jet, an ultrasonic bath with enzymatic cleaner, and an autoclave. Lastly, group E used a prophy jet and an autoclave. The control group consisted of 10 new and sterile HAs. Residual protein concentration was determined by a Micro BCA protein assay (Thermo Fisher Scientific), while HAs from each group were stained with Phloxine B and macroscopically examined for the presence of debris. To examine the inflammatory potential, human primary macrophages were exposed to HAs, and supernatant levels of nine cytokine and chemokine profiles were analyzed using a multiplex bead assay. Results: All test groups showed differences in the degree of visual decontamination compared to controls. Groups D and E displayed the most effective surface debris removal and reduced protein concentration, while group A was the least effective. However, compared to controls, all test groups showed high levels of inflammatory cytokine secretion via multiplex assay for up to 5 days. Conclusions: Our study found that decontamination of uHAs utilizing enzymatic cleaners failed to reestablish inert HA surfaces and prevent an inflammatory immune response in vitro. Clinicians should not reuse HAs even after attempts to decontaminate and sterilize HA surfaces.

Purpose: To complete a reanalysis study of two similarly designed prospective controlled studies exploring prognostic factors associated with the surgical outcomes of reconstructive treatment of peri-implantitis. Materials and Methods: Individual patient data of both studies were gathered. The initial study employed a submerged healing approach via primary wound closure with implant suprastructure removal and complete coverage of grafted sites. The second study employed a nonsubmerged healing protocol in which healing abutments were kept in place and the implants were not fully submerged. Both studies measured all prognostic factors at similar time points throughout 1 year and included clinical defect fill (DF) and radiographic defect fill (RDF), reduction of pocket depth (PDR), and bleeding on probing (BoP). Multilevel regression was used for statistical assessment of outcomes relative to the impact of site, local, surgical, and patient-related variables. Results: Overall, 59 implants (30 submerged and 29 nonsubmerged) were treated. Statistically significant higher DF (on average 0.9 mm higher), RDF (1.7 mm), and PDR (1.3 mm) were observed when a submerged reconstructive approach was performed, whereas BoP reduction was similar. After controlling for treatment (submerged/ nonsubmerged), there were no other significant associations with patient-related (age, sex, smoking, prior periodontitis etc), or implant-related (previous prosthesis type, arch, keratinized tissue width [KTW], etc) factors. Conclusions: Within the study’s limitations, we conclude that a submerged reconstructive approach for surgical management of peri-implantitis leads to significantly enhanced clinical and radiographic outcomes when compared to a nonsubmerged approach. 

Purpose: To assess the healing process of the extraction socket and the dimensional changes that occur after alveolar ridge preservation utilizing a polylactide-co-glycolide scaffold (PLGA). Materials and Methods: The present study involved the extraction of 28 teeth from 14 patients. The total number of sockets was 28, which were divided into two groups consisting of 14 test sockets and 14 control sockets. The study group (SG) was subjected to socket preservation with a PLGA scaffold while the control group (CG) was left for spontaneous healing. The dimensions were measured before and after operation at 1, 3, and 5 mm below the alveolar crest horizontally and the height of buccolingual bone vertically. Results: According to the histologic analyses, the PLGA scaffold was resorbed within 4 months. CBCT imaging revealed a decrease in the horizontal crest dimension at three distinct coronoapical levels in SG, measuring 2.05 ± 1.05 mm at –1 mm, 1.51 ± 0.89 mm at –3mm, and 0.92 ± 0.7 mm at–5mm.CG showed readings of 1.22 ± 1 at–1mm, 0.92 ± 0.67at–3mm, and 0.73 ± 0.69 at –5 mm. In comparison to CG, SG showed a significant reduction in horizontal losses at –1 mm. Vertical crest dimensions decreased by 1.64 ± 1.11 mm for the buccal bone height and by 1.56 ± 1.08 mm for lingual bone height in SG; in CG, the buccal and lingual bone height had mean values of 2.08 ± 1.44 mm and 1.73 ± 1.27 mm, respectively. There was no statistically significant difference observed in the vertical losses between the groups. Conclusions: Following a period of 4 months, the PLGA scaffold was completely resorbed. Based on CBCT measurements, horizontal resorption was lower than CG at –1 mm coronally. 

Purpose: To evaluate the efficacy of using a customized xenograft shell with a 1:1 mixture of particulate xenograft and autogenous bone for the reconstruction of horizontally deficient anterior maxillary alveolar ridges. Materials and Methods: CBCT images of the atrophic maxilla of eight patients were acquired and generated into 3D models. The data were transferred to a 3D printer for fabrication. During the surgery, xenograft blocks were manually sliced and customized on the 3D-printed models into bone shells. Then they were fixed to the atrophic site, and the gap was augmented with a 1:1 mixture of particulate xenograft and autogenous bone. Results: Clinical assessment showed no adverse effects; however, one patient exhibited wound dehiscence. The mean difference between the preoperative and 6-month postoperative CBCTs showed a net average bone gain of 4.06 mm at 2 mm from the crest and 4.34 mm at 5 mm from the crest, which was statistically significant. On the other hand, a statistically significant graft resorption of 1.41 mm at 2 mm from the crest and 2.19 mm at 5 mm from the crest was found when the mean difference between the immediate and 6-month postoperative CBCTs was calculated. Conclusions: Within the limitations of the study, the use of xenograft shells as a barrier for maxillary alveolar ridge reconstruction is a predictable technique; however, further investigations regarding the required time for graft consolidation are required. 

Purpose: To assess the survival of double-crown-retained implant-and-tooth-supported removable partial dentures (DCR-ITSRPDs), evaluate abutment survival, and identify first aftercare measures. Materials and Methods: The influence of various factors on the survival of the DCR-ITSRPDs and the abutments were observed in this retrospective and clinical follow-up study using the Kaplan-Meier estimate. In addition, the first-required aftercare measure for each prosthesis was evaluated. Results: In total, 47 DCR-ITSRPDs were investigated (mean observation: 4.3 ± 3.8 years; max: 14.3 years), 3 of which (6.4%) had to be replaced. The survival probability for DCR-ITSRPDs was 100% at 5 years and 75% at 10 years. A total of 297 abutments (120 natural teeth and 177 dental implants) were observed, 22 of which (7.4%; 6 teeth and 16 implants) failed. The survival probability for teeth was 90.2% at the 5- and 10-year mark; for dental implants, it was 90.4% at 5 years and 76.3% at 10 years. Conclusions: DCR-ITSRPDs are a successful and durable treatment option for patients with substantially reduced residual dentitions. Both prostheses and abutments show good survival times after 5 and 10 years in function. The patient-associated factors tested showed no influence on the survival of DCR-ITSRPDs and abutments. Peri-implant infection was the decisive factor for abutment loss; therefore, regular dental prophylaxis and examinations are of major importance.  Schlagwörter: removable dental prosthesis, double crown, dental implants, tooth-implant supported, survival

Purpose: To investigate how well an implant stability quotient (ISQ) represents resonance frequency. Materials and Methods: Benchtop experiments on standardized samples that replicated a mandibular premolar site were conducted to correlate an ISQ value and a resonance frequency to synthetic bone density and an incremental insertion torque; then, a frequency spectrum analysis was performed to check the validity of the resonance frequency analysis (RFA). Brånemark Mk III implants (4 × 11.5 mm; Nobel Biocare) were placed in Sawbones test models of five different densities (40, 30, 40/20, 20, and 15 PCF). An incremental insertion torque was recorded during implant placement. To perform stability measurements, the test models were partially clamped in a vise (unclamped volume: 10 × 20 × 34 mm). A MulTipeg (Integration Diagnostics) was attached to the implants, and a Penguin (Integration Diagnostics) RFA measured ISQ. Simultaneously, the MulTipeg motion was monitored via a laser Doppler vibrometer and processed by a spectrum analyzer to obtain the resonance frequency. Tightness of the clamp was adjusted to vary the resonance frequency. A statistical analysis produced a linear correlation coefficient (R) among the measured ISQ, resonance frequency, and incremental insertion torque. Results: The resonance frequency had high correlation to the incremental insertion torque (R = 0.978), confirming the validity of using RFA for this study. Measured ISQ data were scattered and had low correlation to the resonance frequency (R = 0.214) and the incremental insertion torque (R = 0.386). The spectrum analysis revealed the simultaneous presence of multiple resonance frequencies. Conclusions: For the designed benchtop tests, resonance frequency does indicate implant stability in view of Sawbones density and incremental insertion torque. However, ISQ measurements do not correlate to the resonance frequency and may not reflect the stability when multiple resonance frequencies are present simultaneously. Schlagwörter: dental implants, stability, Implant Stability Quotient (ISQ), resonance frequency analysis.

Purpose: To compare the effect of taper, length, angle, and number of vertical axial walls on the retentive strength of a cemented crown on a partially customized hybrid abutment in the esthetic zone. Materials and Methods: A total of 35 metal copings were used and divided into two groups. One group had 30 copings cemented to their corresponding 8-degree tapered abutment with lengths from 3 to 8 mm, increasing in 1-mm increments (5 copings per length). The other group had the remaining 5 copings and consisted of a standardized metal coping that matched a hexagonal abutment with 3-mm vertical axial walls and the sequential removal of 1, 2, and 3 contiguous vertical axial walls. Dislodgment tests were performed for all copings in both groups. Maximum retentive forces were measured in retentive strength (kgF), with a conversion factor of 9.807 N = 1 kgF. Results: At each tapered abutment length, the retentive strength increased proportionally and was significantly different, ranging from 31.67 ± 4.10 kgF to 67.68 ± 11.22 kgF (F [5,24] = 20.46, P < .001). An unmodified hexagonal abutment demonstrated the highest retentive strength (70.15 ± 12.97 kgF). The sequential removal of 1, 2, and 3 contiguous vertical axial walls of the hexagonal abutment resulted in retentive strength values of 59.89 ± 10.06 kgF, 57.01 ± 9.62 kgF, and 55.99 ± 9.35 kgF, respectively, with no significant difference (P > .05) in strength. Conclusions: A partially customized abutment with vertical axial walls on one side and a profile reduction on the opposite side can provide comparable retention to cemented copings at one-third the length and at one-sixth the surface area of an 8-mm abutment with an 8-degree taper. 

Purpose: To investigate the effects of sinus membrane stabilization (via suturing) and dental implant placement on the endo-sinus bone formation in lateral sinus elevations performed without grafting. Materials and Methods: Maxillary sinus elevation surgery using the lateral approach was performed bilaterally on 30 New Zealand white rabbits. The maxillary sinus areas were divided into control and test groups. In the control group, a titanium screw was placed after sinus membrane elevation; in the test group, the sinus membrane was sutured to the lateral walls, and a titanium screw was placed in the center of the alveolar crest. The subjects were sacrificed at 4 and 8 weeks. Then samples were collected, and a microcomputed tomography (micro-CT) analysis was performed. In addition, the volume of newly formed bone, percentage of osseointegration, sinus volume, residual bone height, and implant protrusion length were measured using micro-CT analysis. Results: The sinus volume, volume of newly formed bone, and percentage of osseointegration in the test group were significantly higher than in the control group at 4 weeks (P = .01, P = .04, P = .02, respectively). While the volume of newly formed bone was 17.1 ± 3.08 mm³ in the control group, it was 26.9 ± 14.26 mm³ in the test group at 4 weeks. The volume of newly formed bone significantly decreased from 26.9 ± 14.26 mm³ to 17 ± 3.66 mm³ at 8 weeks (P = .02). No significant difference in residual bone height was found at 4 and 8 weeks (P = .07). No significant difference in implant protrusion length was found between the control and test groups (P = .18). Protrusion length and new bone formation in the sinus showed a negative relationship (P = .01). Conclusions: Suturing the sinus membrane to the lateral sinus wall is an effective approach for increasing osseointegration, bone volume, and sinus volume in the short term. A slow-absorbing suture material can be used to maintain sinus and bone volumes in the long term.

Purpose: To evaluate the dimensional accuracy of implant impressions obtained using five different tray types and two techniques. Materials and Methods: A partially dentate maxillary Kennedy Class II model was created as a reference model through 3D printing. Then, implant analogs 4.3 mm in diameter were placed at the first premolar, first molar, and second molar sites. Five types of trays were used to create impressions: (1) metal stock trays, (2) plastic stock trays, (3) custom trays fabricated using liquid crystal display (LCD), (4) custom trays fabricated using fused deposition modeling (FDM), and (5) custom trays fabricated using urethane dimethacrylate (UDMA) resin. Open and closed tray techniques were also compared. In total, 150 impressions were obtained. The reference model and impressions were scanned using a laboratory scanner. Additionally, the positional and angular deviations of implants with different tray types and techniques were evaluated using the superimposition method. Results: There was no statistically significant difference (P > .05) between the impression accuracy with the different tray types and impression techniques. The angular deviations with plastic and UDMA trays were greater than those with metal, FDM, and LCD trays. Angular deviation at the second molar was greater when using closed plastic trays compared to open plastic trays. The highest and lowest positional deviations were observed at the first molar implant with an open plastic tray impression (mean ± SD of 62.46 ± 28.54 mm) and a closed LCD tray impression (36.59 ± 29.93 mm). The greatest angular deviation was observed with an open FDM tray impression at the first premolar implant (0.067 ± 0.024 degree), and the lowest angular deviation was observed with a closed metal stock tray impression at the second molar implant (0.039 ± 0.025 degree). Statistical differences were detected using the Mann-Whitney U test for paired groups and the Kruskal-Wallis test for groups with more than three comparisons (P > .05). Conclusions: Plastic and metal stock trays or conventional and 3D-printed custom trays can be used to obtain implant impressions for maxillary partially edentulous arches with similar dimensional accuracy. The five tray types and two techniques may be safely used to obtain impressions of partially edentulous maxillary arches with three implants. Schlagwörter: Keywords: implant, deviation, accuracy, 3D, impression

Purpose: To examine the behavior and function of human gingival fibroblasts growing on healing abutments with or without laser-textured topography. Materials and Methods: Human primary gingival connective tissue fibroblasts were cultured on healing abutments with machined or laser-textured (Laser-Lok, BioHorizons) surfaces. Cellular and molecular responses were evaluated by a variety of tests, including cell density assay (WST-1), fluorescence microscopy, real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and detachment tests. Results: The machined surface showed monodirectional traces and scratches from milling, whereas the laser-textured surface showed a distinct morphology consisting of monodirectional mesoscale channels (15-μm pitch) and woven oblique microridges formed within the channels. There were no differences in initial fibroblast attachment, subsequent fibroblast proliferation, or collagen production between the machined and laser-textured surfaces. Fibroblasts growing on a laser-textured surface were found to spread in one direction along the mesochannels, while cells growing on machined surfaces tended to spread randomly. Fibroblasts on laser-textured surfaces were 1.8 times more resistant to detachment than those on machined surfaces. An adhesive glycoprotein (fibronectin) and transmembrane adhesion linker gene (integrin β-1) were upregulated on laser-textured surfaces. Conclusions: The increased fibroblast retention, uniform growth, and increased transcription of cell adhesion proteins compellingly explain the enhanced tissue-level response to laser-created and hybrid-textured titanium surfaces. These results provide a cellular and molecular rationale for the tissue reaction to this unique surface; in addition, they support its extended use, from implants and healing abutments to diverse prosthetic components where enhanced soft tissue responses would be desirable.  Schlagwörter: Laser-Lok, microchannels, abutments, implant, soft tissue attachment, laser-textured

Purpose: To evaluate the clinical and radiographic results of simultaneous implant placement using transcrestal sinus floor elevation (TSFE) with and without enamel matrix derivative (EMD) application. Materials and Methods: Twenty-four patients were randomly assigned into two groups: The EMD+TSFE group (n = 13 patients, 20 implants) received TSFE with EMD application, and the TSFE group (n = 11 patients, 20 implants) received TSFE without EMD application. The patients were recalled at 3 (T3) and 12 (T12) months postsurgery. The residual bone height (RBH), implant protrusion length (IPL), peri-implant sinus bone level (SBL), endo-sinus bone gain (ESBG), and implant stability (ISQ) were measured. Multivariate regressions were performed for the groups. Results: At T3, the ESBG was 3.72 ± 0.85 mm in the EMD+TSFE group and 3.10 ± 0.05 mm in the TSFE group, and there were statistically significant differences (P < .05). However, there were no statistically significant differences in ESBG at T12 between the groups (P > .05). ISQ values did not show a statistical difference between the groups at T1 and T3, but at T3 in the TSFE+EMD group, there was a statistical increase in the intragroup evaluation compared to the TSFE group. Conclusions: The use of EMD in TSFE procedures is effective in new bone formation at the apical part of the implant during the early healing period, but in the long term, no significant difference was shown between cases in which EMD was or was not used in terms of new bone formation and primary and secondary stabilization.  Schlagwörter: maxillary sinus, regeneration, dental implant, resonance frequency analysis

Purpose: To quantify the clinical accuracy of a robotically assisted implant guidance system in partially edentulous patients without the use of postoperative CBCT. Materials and Methods: A total of 10 implants (7 patients) were placed in partially edentulous patients utilizing a robotically assisted implant guidance system. Following the implant placement, an intraoral scan was performed to register the implant position after attaching a scan body. The virtual plan and the postoperative intraoral scan with the scan bodies were exported as STL files and superimposed, and discrepancies were analyzed using Geomagic Control X software. Positional deviations were measured between the midpoint of the platform and apex of the planned and achieved implant positions. Results: Seven of the 10 implants in this study were defined as fully robotically guided, while 3 were partially robotically guided. For the fully robotic dynamically guided group, the mean deviation at the midpoint of the restorative platform of the implant, the apex of the implant, the top of the scan body, and the mean angular deviation were 1.31 ± 0.46 mm, 1.58 ± 0.61 mm, 1.11 ± 0.57 mm, and 2.34 ± 1.71 degrees, respectively. For the partially robotic dynamically guided cases, these values were 1.31 ± 0.49 mm, 1.45 ± 0.3 mm, 1.74 ± 0.47 mm, and 3.75 ± 2.53 degrees, respectively. Eight of the 10 implants (irrespective of full or partial guidance) showed a buccal displacement. Conclusions: Robotic surgery offers a level of accuracy similar to fully guided implant placement, without the need for a physical template, and allows for changes in the surgical plan at any time. The analytical method described in this study is an effective and radiation-free quality-control tool that can be used in implant dentistry as well as in other areas of dental research. 

Purpose: To answer the following question: “Do recombinant, purified, and concentrated growth factors enhance the regenerative potential of particulate bone graft substitutes in maxillary sinus floor augmentation (MSA)?” Materials and Methods: Human studies comparing histomorphometric data on new bone formation, residual graft material, and fibrous tissue ratio (outcomes of interest) following MSA procedures employing particulate bone grafts/substitutes in combination or not with growth factors were retrieved from PubMed/MEDLINE, Web of Science, Cochrane, and Scopus online databases and complemented with a hand search. Controlled studies published in English up to December 2022 and reporting on histomorphometric data expressed as volume percentage of the outcomes of interest were considered. Risk of bias was assessed, and a meta-analysis was performed to investigate the effects of supplementary growth factors on new bone formation, remaining graft particles, and fibrous tissue ratio. Results: Data were included from 613 samples in 477 patients reported in 22 publications. Meta-analysis showed that platelet-rich plasma or platelet-rich fibrin resulted in 49% more new bone formation than in control group areas (P = .004), and those areas supplemented with growth factors presented 57% less residual graft particles after healing (P < .0001). A significant (P = .03) 1.85-fold increase in connective tissue formation was noted in areas treated with recombinant human bone morphogenetic proteins (rhBMPs) after healing. Conclusions: Selective supplementary growth factors may enhance new bone formation and accelerate particulate graft turnover, while rhBMP may significantly increase connective tissue formation in MSA procedures in humans. 

Purpose: To investigate whether genetic variations in cytokine genes involved in the pathogenesis of peri-implantitis are associated with the occurrence of peri-implantitis, an issue that remains controversial and may vary according to the population evaluated. Materials and Methods: A cross-sectional analytical study was carried out on 102 Caucasian Portuguese individuals who were divided into two groups: (1) 43 individuals with peri-implantitis and (2) 59 individuals with good peri-implant health. Samples from the buccal mucosa were obtained, and genetic analysis was performed using the real-time polymerase chain reaction (PCR) technique for IL-1A and IL-1B and PCR for IL-1RN. Results: The IL-1A-889 C/T polymorphism presented with a higher prevalence of the less common allele (T allele) in patients with peri-implantitis (27.9%) than in healthy patients (16.9%), but without statistical significance (P = .060). For the IL-1B+3954 C/T and IL-1RN (variable number of tandem repeats [VNTR]) polymorphisms, analysis revealed that the allele and genotype frequencies did not differ significantly between groups. There was a significant association between a history of periodontitis and peri-implantitis (P = .020). Conclusions: The evaluated genetic polymorphisms had no influence on the occurrence of peri-implantitis in the study population. Further research into genetic variations in different populations is needed to elucidate the role of genetic factors in the onset and progression of peri-implant disease.  Schlagwörter: dental implants, peri-implantitis, interleukin-1 receptor antagonist protein, interleukin-1, genetic polymorphisms.

Purpose: To investigate the screw loosening and fracture resistance of different hybrid abutment crown restorations after thermomechanical aging. Materials and Methods: Restorations were produced from zirconia, lithium disilicate, and hybrid ceramics with a CAD/CAM system (n = 10). Restorations and titanium bases (Ti-bases) were cemented, and the abutment screws were torqued to 30 Ncm. They were retorqued after 10 minutes, and then the removal torque values (RTVs) were measured. After 250,000 and 500,000 cycles of thermomechanical aging were completed, the RTVs were measured again, and removal torque loss (RTL) ratios were calculated. The specimens were subjected to a fracture resistance test after 750,000 cycles of thermomechanical aging, and the load at failure was recorded as the fracture resistance (N). The results were statistically analyzed (α = .05). Results: Aging was effective on the RTVs and RTL ratios (P < .001). The highest RTV was observed before aging; however, the RTVs significantly decreased and RTL ratios significantly increased after aging (P < .05). The fracture resistance values significantly differed among the ceramic materials. All lithium disilicate and hybrid ceramic specimens showed restoration fracture and most of the zirconia specimens showed Ti-base–related failure. Conclusions: Hybrid abutment crowns made of zirconia, lithium disilicate, and hybrid ceramics can withstand the average occlusal forces in the molar region; however, the ceramic type may affect the failure type. Retightening of the abutment screws after 10 minutes following the first tightening and annually may be beneficial to prevent the adverse effects of screw loosening on the integrity of the implant-abutment connection.

Purpose: To measure the surface temperature distribution after using a CO₂ laser to heat titanium dental implants via different power settings, application intervals, and irradiation times. Materials and Methods: A total of 10 tissue-level titanium implants (Screw-Line Promote Plus, Camlog; 4.3 × 11 mm) were placed (EpoFix, Struers) and irradiated with a CO₂ laser (Denta 2, Lutronic) with a wavelength of 10.6 μm at power levels of 4 watts (Group 1), 6 watts (Group 2), 8 watts (Group 3), and 10 watts (Group 4). A continuous beam mode (setting I) and noncontinuous beam modes with 5-second (setting II) and 10-second (setting III) pause intervals were used. For each setting, a total irradiation time of 50 seconds was used and repeated 10 times. The temperature was measured using external thermocouple (Testo) in contact with the implant surface at the implant shoulder, middle, and apex. A linear regression model was used to analyze the data (P = .05). Results: Setting I demonstrated the most rapid increase in implant surface temperature in all three test sites as well as the greatest total temperature at 50 seconds of irradiation time. The greater the pause interval (settings II and III) during the 50 seconds of irradiation, the lower the rate of temperature increase as well as the total temperature in all three test sites and with all power levels. The average temperature difference between the apex and shoulder site was significant for setting III for all groups, but not for any groups in settings I and II. Conclusions: Heating the internal aspect of an implant with a CO₂ laser produces different temperature distribution profiles depending on the laser power level and the application interval. Laser-beam irradiation leads to a temperature gradient, which is greatest at the implant apex and smallest at the implant shoulder. 

Purpose: To evaluate the correspondence between output from a new artificial intelligence tool (AIT) and clinician evaluation regarding the immediate loading suitability of dental implants based on insertion torque curves recorded during implant placement in an in vitro test. The secondary aim was to analyze peak insertion torque (PIT) and variable torque work (VTW) values of the implants. Materials and Methods: The study was performed with four different densities of artificial bone blocks of solid rigid polyurethane without a cortical layer. Five types of implants with different macrogeometries were used. A total of 140 implants (7 implants of each type in the four polyurethane blocks) were inserted. Immediately after implant placement, the insertion torque curves were classified by the operator as suitable (S) or nonsuitable (NS) for immediate loading. The same curves were then analyzed by the new AIT, which classified them as belonging to the “YES” or “NO” class. For each implant, PIT and VTW values were also recorded. Results: The correspondence between clinician and AIT evaluation was 99.3%, with only one false negative reported by the algorithm analysis. The AIT was found to have a sensitivity of 98.95%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.8%. Mean PIT of the whole sample was 34.19 ± 19.43 Ncm, while mean VTW was 2,266.89 ± 1,993.73 Ncm. Statistically significant differences were found between implant systems in the whole sample and according to density of the polyurethane block. Conclusions: The AIT showed a high level of accuracy in the prediction of immediate loading suitability of dental implants based on the provided insertion torque curves. All the implants used in the in vitro test achieved good levels of primary stability, except when inserted in the least-dense polyurethane block. Clinical studies conducted with larger samples and more clinicians are necessary to confirm these results. 

Purpose: To assess the complications, satisfaction, and quality of life of patients rehabilitated with delayed and immediate loading of single crowns. Materials and Methods: An electronic search was conducted in PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, and Embase databases up to February 2023. Only prospective studies and randomized and nonrandomized clinical trials comparing immediate and delayed loading were included. For the quantitative analysis, dichotomous and consistent variables were evaluated with a 95% confidence interval. Results: A total of 20 studies were evaluated. No statistically significant difference was observed between protocols: satisfaction (I²: 0%; P = .42), quality of life (I²: 0 %; P = .05), biologic complications (I²: 9%; P = .17), mechanical complications (I²: 58%; P = .84), and survival rate (I²: 0%; P = .38). The subgroup analysis showed significant differences only for marginal bone loss (MBL) when immediate implants were placed in the mandible (I²: 15%; P = .01) and posterior zone (I²: 0%; P = .001). Conclusions: Complications and patient-centered outcomes for immediate single-implant crowns were comparable to delayed loading. Scientific evidence showed no significant difference between loading protocols for survival rates. Note that several factors could interfere with the complication events, implant failures, and MBL. The subgroup analysis showed that only immediate implants placed in the posterior mandible had a higher and statistically significant mean MBL. Schlagwörter: immediate dental implant loading, implant-supported dental prosthesis, patient satisfaction, quality of life, survival rate