Different protocols and procedures for sinus lift and implant placement are available, generally involving the use of grafts to increase the tissue volume and/or prevent the Schneiderian membrane from collapsing. Among xenografts, deproteinised bovine bone graft (DBBP) is frequently used in sinus lift procedures. Leaving an ungrafted space following membrane elevation has proven to have a bony regenerative potential as well. This study aimed to compare the clinical and histological features of sinus lift surgery performed with or without biomaterials.
Patients with severe maxillary posterior atrophy (residual bone height 2–6 mm and residual crest thickness ≥4 mm), and in need of sinus lift surgery to allow the placement of three implants were enrolled and randomly divided into two groups. They underwent sinus lifts with DBBP (control) or with a graftless technique (test) and immediate placement of two implants (a mesial and distal one). After 6 months, a bone sample was retrieved from the area between the previously inserted fixtures, and a third, central implant was placed. The collected bone samples were analyzed morphologically and histomorphometrically. The patients were provided with prosthetic restorations after 6 months and followed up for 5–12 years.
Ten patients were enrolled in the test and nine in the control group. The 6-month follow-up showed in the control group an average augmentation of 10.31 mm (±2.12), while in the test group it was 8.5 mm (±1.41) and a success rate of 96.3% in the control and 86.7% in the test group (p > 0.05). The histological analysis evidenced the presence of new bone tissue surrounded by immature osteoid matrix in the test group, and a variable number of DBBP particles surrounded by an immature woven bone matrix in the control group.
The results of the present trial indicate that, with residual bone height of 2–6 mm and residual crest thickness ≥4 mm, sinus lift surgery with or without biomaterials followed by implant restoration, produces similar clinical and histological outcomes.
To assess navigation accuracy for complete-arch implant placement with immediate loading of digitally prefabricated provisional.
Consecutive edentulous and terminal dentition patients requiring at least one complete-arch FDP were treated between December 2020 and January 2022. Accuracy was evaluated by superimposing pre-operative and post-operative cone beam computed tomography (CBCT), recording linear (mm) and angular (degrees) deviations. T-tests were performed to investigate the potential effect of the registration algorithm (fiducial-based vs. fiducial-free), type of references for the fiducial-free algorithm (teeth vs. bone screws), site characteristic (healed vs. post-extractive), implant angulation (axial vs. tilted), type of arch (maxilla vs. mandible) on the accuracy with p-value <0.05.
Twenty-five patients, 36 complete-arches, and 161 implants were placed. The overall mean angular deviation was 2.19° (SD 1.26°). The global platform and apex mean deviations were 1.17 mm (SD 0.57 mm), and 1.30 mm (SD 0.62 mm). Meaningful global platform (p = 0.0009) and apical (p = 0.0109) deviations were experienced only between healed and post-extraction sites. None of the analyzed variables significantly influenced angular deviation. Minor single-axis deviations were reported for the type of jaw (y-axis at implant platform and apex), registration algorithm (y-axis platform and z-axis deviations), and type of references for the fiducial-free algorithm. No statistically significant differences were found in relation to implant angulation.
Within the study limitations navigation was reliable for complete-arch implant placement with immediate loading digitally pre-fabricated FDP. AI-driven surface anatomy identification and calibration protocol made fiducial-free registration as accurate as fiducial-based, teeth and bone screws equal as references. Implant site characteristics were the only statistically significant variable with healed sites reporting higher accuracy compared to post-extractive. Live-tracked navigation surgery enhanced operator performance and accuracy regardless of implant angulation and type of jaw. A mean safety room of about 1 mm and 2° should be considered.
The aim of this work is to present a new protocol for implant surgical planning which involves the combined use of artificial intelligence (AI) and mixed reality (MR).
This protocol involves the acquisition of three-dimensional (3D) patient data through intraoral scanning (IOS) and cone beam computed tomography (CBCT). These data are loaded into AI software which automatically segments and aligns the patient's 3D models. These 3D models are loaded into MR software and used for planning implant surgery through holography. The files are then exported and used to design surgical guides via open-source software, which are 3D printed and used to prepare the implant sites through static computer-assisted implant surgery (s-CAIS). The case is finalized prosthetically through a fully digital protocol. The accuracy of implant positioning is verified by comparing the planned position with the actual position of the implants after surgery.
As a proof of principle, the present protocol seems to be to be reliable and efficient when used for planning simple cases of s-CAIS in partially edentulous patients. The clinician can plan the implants in an authentic 3D environment without using any radiology-guided surgery software. The precision of implant placement seems clinically acceptable, with minor deviations.
The present study suggests that AI and MR technologies can be successfully used in s-CAIS for an authentic 3D planning. Further clinical studies are needed to validate this protocol.
The stability of soft tissue volume around dental implants is an important factor for the final esthetic outcome. The main objective of this study was to compare volume stable collagen matrix (VCMX) versus connective tissue graft (CTG) in the augmentation of soft tissue profiles in single implant sites with a class I Siebert ridge defect.
Twenty patients (14 females and 6 males) were enrolled in the present study. After implant placement and augmentation of the buccal defect by VCMX or CTG, post-operative evaluation of the volumetric changes at the augmented implant site was carried out at 3, 6, and 9 months as primary outcome, clinical and radiographic soft tissue thickness were carried out at baseline and 9-month intervals, visual analog scale (VAS) and oral health impact profile-14 (OHIP14) were recorded 2 weeks after the surgery.
A statistically significant difference in soft tissue volume was found between baseline and 3, 6, and 9 months postoperatively in both groups with the highest value at 9 months (136.33 ± 86.80) (mm3) in VCMX and (186.38 ± 57.52) (mm3) in CTG. Soft tissue thickness was significantly increased in both groups at 9 months in comparison to baseline. However, there was a significantly higher increase in soft tissue thickness at 9 months in CTG (3.87 ± 0.91) than in VCMX (2.94 ± 0.31). Regarding the radiographic soft tissue thickness, there was a statistically significant increase in both groups at 9 months in comparison to baseline. However, there was a statistically higher increase in the radiographic soft tissue thickness at 9 months in CTG (3.08 ± 0.97) than in VCMX (2.37 ± 0.29). VAS showed a statistically lower value in VCMX (0.4 ± 0.7) than CTG (2.8 ± 1.48). The OHIP recorded lower values in the VCMX group than the CTG group with no statistical significance. In addition, there was no difference in the PES between the two groups.
The present study showed that CTG and VCMX were both effective in soft tissue augmentation around implants in the esthetic zone. However, CTG proved more efficient in increasing peri-implant soft tissue volume and mucosal thickness around single implants at a 9-month follow-up period. VCMX was associated with less pain or discomfort and reduced patient morbidity, as reflected by the significantly reduced VAS value in the VCMX group.
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.
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.
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°.
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.
To investigate the effect of mid-buccal peri-implant keratinized mucosa width (KMW) ≥2 mm or peri-implant KMW >0 mm and <2 mm on the long-term outcomes of peri-implantitis reconstructive treatment.
Twenty-nine patients (40 implants; mean follow-up: 9.2 ± 1.4 years) with at least one implant affected by peri-implantitis and surgically treated through a reconstructive procedure followed by a submerged healing were included. Patients were categorized according to their initial KMW: Group 1 (KMW ≥2 mm) and Group 2 (KMW >0 mm and <2 mm). Peri-implant clinical and radiographic parameters and a dedicated composite outcome were assessed at different follow-up visits during supportive peri-implant therapy for up to 10 years. Regression analyses were utilized to identify possible risk/predictive indicators for probing pocket depth (PPD) change and treatment success at the latest follow-up.
The mean PPD did not exhibit any statistical difference from the baseline to the latest follow-up between the groups at both patient and implant levels. Long-term treatment success was 46.6% (Group 1) and 42.6% (Group 2) at patient level, it was 42.8% (Group 1) and 33.3% (Group 2), respectively, at implant level (p > 0.05). Group 1 demonstrated significantly higher vertical defect depth reduction than Group 2 (p = 0.018). Presence of buccal bony wall and mean PPD at the baseline were found to be associated with mean PPD change, while KMW at 6 months following surgery was identified as the only significant indicator for treatment success (p < 0.05).
Implants with KMW ≥2 mm did not present significantly better long-term clinical outcomes following reconstructive therapy than those exhibiting KMW >0 mm and <2 mm. However, KMW values at the end of healing phase following a submerged approach had a significant impact on long-term treatment success.
To compare the osteoblastic activity and osteogenic potential of autogenous particle harvesting during implant surgery using low-speed drilling without irrigation and high-speed drilling with irrigation.
Thirty patients with bilateral missing teeth of 3.6 and 4.6 were randomized into two groups (Group 1: low-speed drilling without irrigation and Group 2: high-speed drilling with irrigation) and 60 single dental implants were placed. The temperature at the tip of each drill was recorded and the harvested bone was weighed; particle size and Ca and P levels were also analyzed. After osteoblast culture, cell viability, cell cycle assay, cell migration, vascular endothelial growth factor (VEGF) concentration, and mineralized nodule formation were assessed.
Although the temperature of the drills was slightly higher in Group 1, no statistically significant differences were observed (p ≤ 0.05); however, the amount of harvested bone was higher (p < 0.001) and the size of the particles was higher (p = 0.019). In relation to osteoblastic activity and osteogenic potential, higher cell proliferation, higher number of cells in G2/M and S phases, higher cell migration capacity, higher VEGF concentration, and higher amount of mineralized nodule formation were observed in Group 1.
Low-speed drilling without irrigation does not result in a significant increase in bone temperature compared to conventional drilling. However, a greater amount of bone is obtained; in addition, osteoblastic activity and osteogenic potential are higher with this technique, but further clinical studies are necessary.
To investigate whether a progressive marginal bone loss (PMBL) occurring beyond the initial bone remodeling (IBR) is linked with bleeding on probing.
A total of 70 partially edentulous patients exhibiting 112 two-piece bone-level implants were included in this retrospective study. Panoramic radiographs were obtained after implant insertion (T0), after delivery of a final prosthetic restoration (T1) and subsequently during the 1-(T2), 5-(T3), 10-(T4), and 15-years (T5) follow-up visits. At each time point, radiographic marginal bone levels were assessed from the implant shoulder to the first bone-to-implant contact at mesial and distal aspects. The IBR was defined as a bone loss occurring up to prosthesis delivery, that is, from T0 to T1. The PMBL was defined as bone loss occurring after T1. At T2, T3, T4, and T5, the presence or absence of bleeding on probing (BOP) was recorded at four sites. A median regression with mixed models was performed to assess the difference of PMBL in PMBL + BOP+ and PBML + BOP− groups.
Over the mean implant functioning time of 4.44 ± 4.91 years, 38 (34%) implants showed no PBML, whereas 74 (66%) implants featured PMBL. Of these, 35 (47%) and 39 (53%) implants were assigned to the PMBL + BOP− and PMBL + BOP+ groups, respectively. The mean PMBL after 1, 5, 10, and 15 years were comparable between implants featuring PMBL with or without BOP. At 1 year, BOP intensity significantly correlated PMBL, with each increase in one BOP-positive site being associated with increase in PMBL by 0.55 mm (p = 0.038), whereas this association was not found at 5, 10, and 15 years. The IBR values in the no PBML, PMBL + BOP+, and PBML + BOP− groups were −0.24 ± 0.31, −0.41 ± 0.59, and −0.24 ± 0.33 mm, respectively, with no significant differences found among the groups.
Progressive bone loss at implant sites is not always linked with bleeding on probing.
To evaluate the histomorphometric and computerized microtomographic (Micro-CT) analysis of the regenerated bone tissue from maxillary sinus augmentation surgery, with and without using the collagen membrane on the external osteotomy window.
Twelve patients were selected for this prospective, controlled, and randomized study. The patients were submitted to bilateral maxillary sinus surgery in a split-mouth design. On the test side, the maxillary sinus augmentation procedure included using Geistlich Bio-Oss® and a Geistlich Bio-Gide® collagen membrane covering the lateral osteotomy window. On the control side, only Geistlich Bio-Oss® was used without the presence of the membrane. After 6 months, the surgeries for implant installation were performed. In this surgical phase, specimens of the regenerated tissue were collected for histological and Micro-CT analysis.
In the histomorphometric evaluation, the mean (±SD) percentages of newly formed bone were 43.9% (±11.5) and 40.8% (±8.9) in the test and control groups, respectively. The corresponding values of the Micro-CT analysis were 36.6% (±3.4) and 37.2% (±4.7) in the test and control groups, respectively. There was no statistically significant difference between the test and control groups in the two methods. In addition, there was no statistically significant difference between the mean percentage of biomaterial remaining between the test and control groups. However, the mean percentage of newly formed bone was significantly higher and the mean percentage of remaining biomaterial was significantly lower in the histomorphometric analysis compared to the values obtained through microtomography.
The additional use of collagen membranes in maxillary sinus surgery does not offer advantages in newly formed bone.
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