OBJECTIVE: The aim of this study was to evaluate the accuracy of 3-dimensional (3D)-printed surgical guides for fully guided immediate implants from different manufacturers.
METHODS: Eighteen 3D printed fully guided surgical guides (split into 3 groups [n = 6] according to their manufacturer: Company, Desktop, or Lab), were used to place 72 implants (n = 24) in identical maxillary models. After placement, the mean global, angular, mesiodistal, buccopalatal, and vertical deviation at the platform and apex of the placed implants, relative to their preoperatively planned positions, was calculated.
RESULTS: Significant differences in global apex deviation, angular deviation, mesiodistal apex deviation, and vertical platform and apex deviation were found between the Lab and Desktop groups (p ≤ 0.007). Significant differences in mesiodistal platform and apex deviation and buccopalatal apex deviation were also found between the Company and Desktop groups (p ≤ 0.005). Finally, significant differences in buccopalatal apex deviation, and vertical platform and apex deviation were found between the Company and Lab groups (p ≤ 0.003). Mean differences between guide groups across all parameters never exceeded 0.5 mm or 1°.
CONCLUSIONS: The choice of 3D printer has a significant effect on the accuracy of fully guided immediate implants. However, the clinical relevance of these differences may be considered limited.

UNASSIGNED: The aim of this study was to investigate the influence of abutment material, alveolar bone density, and occlusal forces on stress distribution around maxillary anterior implants.
UNASSIGNED: An in-vitro study was conducted. The maxillary anterior implant was modeled using a three-dimensional finite element model in D2 and D3 bones with three different abutment materials: titanium, zirconia, and poly-ether-ether ketone (PEEK). Von Mises stress was evaluated after the application of vertical and oblique loads of 100 N, 175 N, and 250 N. Statistical analysis was done by Friedman-Wilcoxon signed-rank test, Mann-Whitney U test, and Kruskal-Wallis test. The probability value <0.05 is considered a significant level.
UNASSIGNED: Stress distribution around D3 bone was higher than D2 bone in all the abutment materials with greater values seen in oblique load than vertical load with insignificant difference (P > 0.05). Statistically insignificant stress values were seen greater in PEEK than titanium or zirconia abutment (P > 0.05). A statistically significant difference was observed between 100 N and 175 N of load (P < 0.05).
UNASSIGNED: PEEK, zirconia, and titanium as abutment material in the anterior region showed similar properties. The stress on the bone was proportionately increased during the vertical and oblique loads suggesting the influence of mechanical load in crestal bone loss rather than the type of abutment material.

Purpose - Compare the morphometric results of immediate implants (Type 1C) with a cylindrical (conventional) or triangular neck, in the anterior region of the maxilla, during 6 months of osseointegration. Materials and Methods - Prospective randomized clinical trial with a sample of 20 individuals randomly assigned to each group (10 triangular neck implants and 10 cylindrical neck implants). Consecutively direct measurements were performed: before (T-1) and after tooth extraction (T0), after implant placement (T1), after 1 month of the submerged implant healing (T2), when placing the healing abutment (T3), after placing the definitive crown (T3), and after 6 months of osseointegration (T4). Results - A significant difference between T1 and T3 in the buccal cortical thickness was identified (0.49Å}0.86mm). Although there was a significant increase in the buccal cortical thickness in both implants, this increase was greater for the triangular neck implants (cylindrical shape: 0.08Å}0.59 vs. triangular neck 0.90Å}0.91mm). It was also observed that implants placed below the buccal bone crest (í-1mm) promote less vertical buccal bone loss than implants placed Ñ-1mm at crest level (-0.65Å}0.52mm vs. -1.42Å}0.86mm). This observation needs to be further investigated in additional studies. Conclusions - The triangular neck implants present an increase in the cortical buccal thickness compared to the cylindrical implants. However, this increase does not fully compensate the remodulation after tooth loss.

Implant-supported rehabilitation in high-risk patients poses significant challenges for the dental team. The presence of comorbidities and increased infection risk can, for example, lead to a higher risk of implant loss. For the therapy to be completed with as few complications as possible, special anamnesis, detailed diagnostics, and a risk analysis based on those findings are indispensable. The aim of all considerations is to keep the risk of infection for the patient with a disease history to a minimum and to strive for an appropriate functional and esthetic therapeutic success. Particularly in the esthetic zone, in addition to the general health risks of the surgical procedure, esthetic aspects are increasingly taken into account in planning. The present article describes the implant-prosthetic replacement of a single anterior tooth in a dialysis patient. Several aspects (regular dialysis, missing buccal lamella, high smile line, functional risk) increased the risk of complications in this case.

OBJECTIVE: To compare immediate implant placement (IIP) with early implant placement (EIP) for single tooth replacement in the aesthetic area in terms of aesthetic, clinical, and patient-reported outcomes.
METHODS: Two independent reviewers conducted an electronic literature search in PubMed, Web of Science, Embase, and Cochrane databases as well as a manual search to identify eligible clinical studies up to February 2023. Randomized Controlled Trials (RCTs) comparing IIP with EIP were included for a qualitative and quantitative analysis. The primary outcome was vertical midfacial soft tissue change. Secondary outcomes were horizontal midfacial soft tissue change, vertical papillary change, pink esthetic score (PES), implant survival, buccal bone thickness, marginal bone level change, patient discomfort, chair time, and patient satisfaction.
RESULTS: Out of 1185 records, 6 RCTs were selected, reporting on 222 patients who received 222 single implants (IIP: 112 implants in 112 patients; EIP: 110 implants in 110 patients) in the anterior maxilla or mandible. Patients had a mean age ranging from 35.6 to 52.6 years and were followed between 8 and 24 months. Two RCTs showed some concerns, and four showed a high risk of bias. Four studies could be included in a meta-analysis on the primary outcome and three only considered cases with an intact buccal bone wall. Meta-analysis failed to demonstrate a significant difference in terms of vertical midfacial soft tissue change between IIP and EIP (mean difference: 0.31 mm, 95% CI [-0.23; 0.86], p = .260; I2 = 83%, p < .001). No significant differences were found for PES (standardized mean difference: 0.92, 95% CI [-0.23; 2.07], p = .120; I2 = 89%, p < .001), implant survival (RR: 0.98, 95% CI [0.93, 1.03], p = .480; I2 = 0%, p = .980), and marginal bone level change (mean difference: 0.03 mm, 95% CI [-0.12, 0.17], p = .700; I2 = 0%, p = .470). Insufficient data were available for meta-analyses of other secondary outcomes.
CONCLUSIONS: In low-risk patients with an intact buccal bone wall, there seems to be no difference between IIP and EIP in terms of aesthetic and clinical outcomes. The strength of this conclusion is rated as low since studies showed an unclear or high risk of bias. In addition, state-of-the-art therapy was only delivered in a minority of studies. Future RCTs should also provide data on patient-reported outcomes since these have been underreported.

OBJECTIVE: To compare connective tissue graft (CTG) with collagen matrix (CMX) in terms of increase in buccal soft tissue profile (BSP) when applied at single implant sites.
METHODS: Patients with a single tooth gap in the anterior maxilla and horizontal mucosa defect were enrolled in a multi-centre randomized controlled trial. All were fully healed sites with a bucco-palatal bone dimension of at least 6 mm, and received an immediately restored single implant using a full digital workflow. Patients were randomly allocated to the control (CTG) or test group (CMX: Geistlich Fibro-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) to increase buccal soft tissue thickness. Primary endpoints were increase in BSP at T1 (immediately postop), T2 (3 months), T3 (1 year) and T4 (3 years) based on superimposed digital surface models. Secondary endpoints included patient-reported, clinical and aesthetic outcomes.
RESULTS: Thirty patients were included per group (control group: 15 males, 15 females, mean age 50.1 years; test group: 14 males, 16 females, mean age 48.2 years) and 50 could be re-examined at T4. The changes in BSP over time were significantly different between the groups (p < .001). At T4, the estimated mean increase in BSP amounted to 0.83 mm (95% confidence interval [CI]: 0.58-1.08) in the control group and 0.48 mm (95% CI: 0.22-0.73) in the test group. The estimated mean difference of 0.35 mm (95% CI: 0.06-0.65) in favour of the control group was significant (p = .021). No significant differences between the groups could be observed in terms of patients\' aesthetic satisfaction (p = .563), probing depth (p = .286), plaque (p = .676), bleeding on probing (p = .732), midfacial recession (p = .667), Pink Esthetic Score (p = .366) and Mucosal Scarring Index (p = .438). However, CMX resulted in significantly more marginal bone loss (-0.43 mm; 95% CI: -0.77 to -0.09; p = .015) than CTG.
CONCLUSIONS: CTG was more effective in increasing buccal soft tissue profile and resulted in less marginal bone loss than CMX. Therefore, CTG remains the gold standard to increase soft tissue thickness at implant sites.
BACKGROUND: This study was registered in ClinicalTrials.gov (NCT04210596).

OBJECTIVE: To assess the impact of the timing of implant placement following alveolar ridge preservation (ARP) on the need for soft-tissue augmentation (STA) and to identify the risk factors for horizontal and vertical soft-tissue loss.
METHODS: Patients with a single failing tooth in the anterior maxilla (15-25) were treated at six centres. Following tooth extraction, they were randomly allocated to the test group (immediate implant placement, IIP) or control group (delayed implant placement, DIP). ARP was performed in both groups and implants were immediately restored with an implant-supported provisional crown. Six months after tooth extraction and ARP, a panel of five blinded clinicians assessed the need for STA on the basis of anonymized clinical pictures and a digital surface model. Lack of buccal soft-tissue convexity and/or mid-facial recession qualified for STA. Pre-operative and 6-month digital surface models were superimposed to assess horizontal and vertical soft-tissue changes.
RESULTS: Thirty patients were included per group (test: 20 females, 10 males, mean age 53.1; control: 15 females, 15 males, mean age 59.8). The panel deemed STA as necessary in 24.1% and 35.7% of the cases following IIP and DIP, respectively. The difference was not statistically significant (odds ratio [OR] = 1.77; 95% confidence interval [CI] [0.54-5.84]; p = .343). Loss of buccal soft-tissue profile was higher following DIP (estimated mean ratio = 1.66; 95% CI [1.10-2.52]; p = .018), as was mid-facial recession (mean difference [MD] = 0.47 mm; 95% CI [0.12-0.83]; p = .011). Besides DIP, regression analysis identified soft-tissue thickness (-0.57; 95% CI [-1.14 to -0.01]; p = .045) and buccal bone dehiscence (0.17; 95% CI [0.01-0.34]; p = .045) as additional risk factors for mid-facial recession. Surgeons found IIP significantly more difficult than DIP (visual analogue scale MD = -34.57; 95% CI [-48.79 to -20.36]; p < .001).
CONCLUSIONS: This multi-centre randomized controlled trial failed to demonstrate a significant difference in the need for STA between IIP and DIP when judged by a panel of blinded clinicians. Based on objective soft-tissue changes, patients with thin buccal soft tissues, with a buccal bone dehiscence and treated with a delayed approach appeared particularly prone to soft-tissue loss.

OBJECTIVE: This in vitro study aimed to assess the positional accuracy during the sequence of static computer-assisted implant surgery (sCAIS) according to the anatomical characteristics of the alveolar ridge.
METHODS: Maxillary bone models with six single tooth gaps including clinical scenarios of healed alveolar ridge (HR), single-rooted (SRS), and three-rooted socket (TRS) morphologies were used in this study. Positional deviations during implant placement procedures were evaluated after the pilot osteotomy (PD), final osteotomy (FD), and implant placement with respect to the pre-planned implant position by using a software package. ANOVA and post hoc analyses were performed.
RESULTS: A total of 90 implants were included in this study. Higher mean angular, crestal, and apical deviations were found after the PD and FD (3.5 ± 2.4°, 0.7 ± 0.3 mm, and 1.4 ± 0.8 mm versus 3.6 ±2.2°, 0.6 ± 0.3 mm, and 1.2 ± 0.6 mm) compared to IP (2.8 ± 1.6°, 0.7 ± 0.3 mm, and 1.2 ± 0.5 mm, p ≤ 0.004). Implants placed in TRS demonstrated higher mean angular, crestal, and apical deviations (4.0 ± 1.7°, 0.8 ± 0.3 mm, and 1.6 ± 0.5 mm) compared to implants placed in SRS (2.5 ± 1.2°, 0.7 ± 0.3 mm, and 1.1 ± 0.4 mm) or HR (2.0 ± 0.9°, 0.5 ± 0.3 mm, and 0.8 ± 0.4 mm, p < 0.001).
CONCLUSIONS: Positional deviations during sCAIS procedures are initiated with the first implant osteotomy and persist throughout the drilling sequence. However, deviations slightly decreased after implant placement. The alveolar ridge morphology is strongly associated with positional deviations. Higher deviations were observed in three-rooted and single-rooted sockets simulating an immediate approach compared to healed sites simulating a delayed protocol.

OBJECTIVE: To compare and report on the performance of implant-supported fixed dental prostheses (iFDPs) fabricated using additive (AM) or subtractive (SM) manufacturing.
METHODS: An electronic search was conducted (Medline, Embase, Cochrane Central, Epistemonikos, clinical trials registries) with a focused PICO question: In partially edentulous patients with missing single (or multiple) teeth undergoing dental implant therapy (P), do AM iFDPs (I) compared to SM iFDPs (C) result in improved clinical performance (O)? Included were studies comparing AM to SM iFDPs (randomized clinical trials, prospective/retrospective clinical studies, case series, in vitro studies).
RESULTS: Of 2\'184 citations, no clinical study met the inclusion criteria, whereas six in vitro studies proved to be eligible. Due to the lack of clinical studies and considerable heterogeneity across the studies, no meta-analysis could be performed. AM iFDPs were made of zirconia and polymers. For SM iFDPs, zirconia, lithium disilicate, resin-modified ceramics and different types of polymer-based materials were used. Performance was evaluated by assessing marginal and internal discrepancies and mechanical properties (fracture loads, bending moments). Three of the included studies examined the marginal and internal discrepancies of interim or definitive iFDPs, while four examined mechanical properties. Based on marginal and internal discrepancies as well as the mechanical properties of AM and SM iFDPs, the studies revealed inconclusive results.
CONCLUSIONS: Despite the development of AM and the comprehensive search, there is very limited data available on the performance of AM iFDPs and their comparison to SM techniques. Therefore, the clinical performance of iFDPs by AM remains to be elucidated.

OBJECTIVE: This study aimed to histologically evaluate the healing at 8 weeks after coronally advanced flap (CAF) with either a superficial (SCTG) or deep palatal connective tissue graft (DCTG), or a collagen matrix (CM) to cover recession defects at teeth and implants.
METHODS: One mandibular side of 6 miniature pigs received each 3 titanium implants 12 weeks after extraction. Eight weeks later, recession defects were created around implants and contralateral premolars and 4 weeks later randomly subjected to CAF + SCTG, CAF + DCTG, or CAF + CM. After 8 weeks, block biopsies were histologically analyzed.
RESULTS: For the primary outcome, i.e., keratinization of the epithelium, all teeth and implants exhibited a keratinized epithelium with no histological differences among them also not in terms of statistically significant differences in length (SCTG 0.86 ± 0.92 mm, DCTG 1.13 ± 0.62 mm, and Cm, 1.44 ± 0.76 mm). Pocket formation was histologically seen at all teeth, around most implants with SCTG and DCTG, however not in the CM implant group. The connective tissue grafts showed hardly signs of degradation, whereas the CM was partly degraded and integrated in connective tissue. The mean gain in gingival height was similar in all experimental groups (SCTG 3.89 ± 0.80 mm, DCTG 4.01 ± 1.40 mm, CM 4.21 ± 0.64 mm). Statistically significant differences were found in the height of the junctional epithelium between the control teeth and the connective tissue groups (p = 0.009 and 0.044).
CONCLUSIONS: In this animal model, the use of either a superficial or deep connective tissue graft or a collagen membrane did not seem to have any impact on the epithelial keratinization around both teeth and implants. All procedures (CAF + SCTG/DCTG/CM) resulted in a long JE that was even longer at implants.
CONCLUSIONS: Deep/superficial palatal connective tissue graft yielded similar keratinization around teeth/implants. Given the absence of pocket formation and inflammatory processes at implants when using a CM, CAF + CM might bear potential clinical benefits.