Histomorphometrical and clinical comparison of submerged and nonsubmerged implants subjected to experimental peri-implantitis in dogs

Bridging the Gap with Nanoparticles: A Novel Approach

Two-piece implants unavoidably present a microgap between the implant and the abutment interface. Although numerous modalities have been attempted to overcome this situation, the implant abutment interface still remains a critical point for microbial colonization, which starts an inflammatory cascade of events eventually compromising the implants. Throughout our life, cells in all biological systems are unprotected to oxidative stress leading to the formation of Reactive oxygen species which is of concern when it comes to placing implants in patients who are periodontally compromised. This necessitates the development of alternative therapeutic modalities, which could counteract as well as prevent the microbial overload and ROS generation thereby improving the longevity of implants. To evaluate and assess the antibacterial, antioxidant and anti inflammatory effectiveness of quercetin-loaded titanium nanocomposites as coatings over healing abutments. Quercetin-loaded titanium nanocomposites were synthesized using green synthesis and confirmation was done using UV spectroscopy. Healing abutments were coated with the formulated nanocomposites, an intra-oral environment was simulated by thermocycling. Their antibacterial, antioxidant, anti-inflammatory, and cytotoxicity were assessed using standard tests. Healing abutments were coated with the formulated nanocomposites, an intra-oral environment was simulated by thermocycling. They showed potent antibacterial, antioxidant, and anti-inflammatory properties, which could prove beneficial in a variety of clinical scenarios in which there is a high risk for implant failure during early osseointegration.

Histomorphometrical and CBCT Evaluation of Tissue Loss Progression Induced by Consecutive, Alternate Ligatures in Experimental Peri-Implantitis in a Dog Model: A Pilot Study

Objectives: Soft and hard tissue breakdown was histologically and radiologically assessed around implants with alternate, consecutively placed ligatures on the same edentulous dog hemimandible. The influence of ligatured implants (LI) on adjacent non-ligatured implants (NLI, as a possible naturally induced peri-implantitis) was also evaluated. Material and Methods: Three months after tooth extraction, five dental implants were placed in the dog hemimandible. Two months after abutment placement, ligatures were placed subsequently two months apart on alternate implants, while both intermediate implants were left without ligatures. Ligatures were kept in place during the entire experiment, and no plaque control measures were taken. Eleven months post-implantation, the animal was sacrificed. Undecalcified ground sections were cut, stained with Masson Goldner and MOVAT Pentachrome and evaluated by light microscopy. Soft and hard tissue loss was assessed using histomorphometric and CBCT parameters. Results: All NLI presented deep false peri-implant pockets on the oral aspect and pronounced vertical bone resorption on the buccal aspect. After 2, 4 and 6 months, during the breakdown period, more than 30% of the bone was lost in LI in all directions, while, despite immediate vicinity, NLI displayed less destruction. Intense inflammation, typical for induced peri-implantitis, was present, with similar intensity in LI as NLI, but in different parts of the lesions. Morphometry confirmed intense soft tissue inflammation, more bone resorption and higher amounts of infiltrated connective tissue in LI when compared with NLI. Conclusion: Within the limits of the present pilot study, the adequacy of the experimental dog model based on ligature-induced peri-implantitis was able to be successfully challenged by non-ligature models of spontaneously occurring peri-implant inflammation, while meeting the requirements for experimental designs with a very small numbers of animals. The influence of implants with severe peri-implantitis on adjacent implants resulted in less than expected tissue loss in the latter accession numbers.

An In-Vivo Comparative Study of the Soft Tissue Response and Esthetics of the Titanium Implant with Titanium Collar by Flapless and Conventional Flap Technique

Background

These days, patients want quick results for tooth replacement and esthetic results. However, there is no direct correlation between the achievement of osseointegration and the outcome of successful treatment always. It is vital to sustaining peri-implant soft tissue health for extensive tenure success of the implant.

Aim

The purpose of this trial was to determine, estimate, and compare the soft tissue retort and esthetics of the titanium implants with titanium collar at periodic intervals by flapless and conventional flap technique before and after prosthesis placement.

Results

The difference in soft tissue indices namely, gingival index, plaque index, and the modified sulcular bleeding index was insignificant between the two implants placed by flapless and open flap technique 2. There was a significant difference amid the probing depths of the two implants after 3 months of prosthesis positioning where the implant placed by flapless technique showed lesser values as compared to the implant placed by the open flap technique 3. The esthetics of the soft tissues surrounding the titanium implant with titanium collar, when compared, presented a significant difference between the two techniques of implant placement.

Conclusion

In conclusion, in recent advancements in dentistry, the flapless technique is becoming prominent because of procedure of minimally invasive surgery in implantology. There are advantages of early re-epithelialization and less inflammation around the soft tissue of the implant in the flapless procedure, provided that the prospective for the establishment of a fully functioning along with aesthetically desirable peri-implant soft tissue collar. The flapless technique accomplishes high degrees of gratification by the patients by shortening the surgery time and minimum invasion to both bone and soft tissue.

A New Strategy Against Peri-Implantitis: Antibacterial Internal Coating

The bacterial biofilm formation in the oral cavity and the microbial activity around the implant tissue represent a potential factor on the interface between bone and implant fixture that could induce an inflammatory phenomenon and generate an increased risk for mucositis and peri-implantitis. The aim of the present clinical trial was to investigate the bacterial quality of a new antibacterial coating of the internal chamber of the implant in vivo at six months. The PIXIT implant (Edierre srl, Genova Italy) is prepared by coating the implant with an alcoholic solution containing polysiloxane oligomers and chlorhexidine gluconate at 1%. A total of 15 healthy patients (60 implants) with non-contributory past medical history (nine women and six men, all non-smokers, mean age of 53 years, ranging from 45-61 years) were scheduled to receive bilateral fixed prostheses or crown restorations supported by an implant fixture. No adverse effects and no implant failure were reported at four months. All experimental sites showed a good soft tissue healing at the experimental point times and no local evidence of inflammation was observed. Real-Time Polymerase Chain Reaction (PCR) analysis on coated and uncoated implants showed a decrease of the bacterial count in the internal part of the implant chamber. The mean of total bacteria loading (TBL) detected in each PCR reaction was lower in treated implants (81038 units/reaction) compared to untreated implants (90057 units/reaction) (p < 0.01). The polymeric chlorhexydine coating of the internal chamber of the implant showed the ability to control the bacterial loading at the level of the peri-implant tissue. Moreover, the investigation demonstrated that the coating is able to influence also the quality of the microbiota, in particular on the species involved in the pathogenesis of peri-implantitis that are involved with a higher risk of long-term failure of the dental implant restoration.

Ligature-induced peri-implantitis and periodontitis in mice

AIM

Peri-implantitis (PI), inflammation around dental implants, shares characteristics with periodontitis (PD). However, PI is more difficult to control and treat, and detailed pathophysiology is unclear. We aimed to compare PI and PD progression utilizing a murine model.

MATERIALS AND METHODS

Four-week-old male C57BL/6J mice had their left maxillary molars extracted. Implants were placed in healed extraction sockets and osseointegrated. Ligatures were tied around the implants and second molars. Controls did not receive ligatures. Mice were sacrificed 1 week, 1 and 3 months (n ≥ 5/group/time point) post-ligature placement. Bone loss analysis was performed. Histology was performed for: haematoxylin and eosin (H&E), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-8 (MMP-8), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), toluidine blue and calcein.

RESULTS

PI showed statistically greater bone loss compared to PD at 1 and 3 months. At 3 months, 20% of implants in PI exfoliated; no natural teeth exfoliated in PD. H&E revealed that alveolar bone surrounding implants in PI appeared less dense compared to PD. PI presented with increased osteoclasts, MMP-8 and NF-κB, compared to PD.

CONCLUSION

PI exhibited greater tissue and bone destruction compared to PD. Future studies will characterize the pathophysiological differences between the two conditions.

Susceptibility of different mouse strains to peri-implantitis

BACKGROUND AND OBJECTIVE

Peri-implantitis (PI) is an inflammatory condition that affects the tissues surrounding dental implants. Although the pathogenesis of PI is not fully understood, evidence suggests that the etiology is multifactorial and may include a genetic component. The aim of this study was to investigate the role of genetics in the development of peri-implantitis.

MATERIAL AND METHODS

Four-week-old C57BL/6J, C3H/HeJ and A/J male mice had their left maxillary molars extracted. Implants were placed in the healed extraction sockets. Upon osseointegration, ligatures were placed around the implant head for 1 or 4 weeks to induce PI. Micro-computed tomography scanning was used to measure volumetric bone loss. Histological analyses were also performed to evaluate collagen organization and the presence of neutrophils and osteoclasts.

RESULTS

Radiographically, comparing the ligature-treated mice, C57BL/6J displayed the greatest amount of bone loss, followed by C3H/HeJ and A/J mice at 1 and 4 weeks. Histologically, at 1 week, C57BL/6J mice presented with the highest numbers of neutrophils and osteoclasts. At 4 weeks, C57BL/6J mice presented with the most active bone remodeling compared with the other two strains.

CONCLUSION

There were significant differences in the severity of peri-implantitis among the different mouse strains, suggesting that the genetic framework can affect implant survival and success. Future work is needed to dissect the genetic contribution to the development of peri-implantitis.

Animal models for peri-implant mucositis and peri-implantitis

The treatment of infectious diseases affecting osseointegrated implants in function has become a demanding issue in implant dentistry. Since the early 1990s, preclinical data from animal studies have provided important insights into the etiology, pathogenesis and therapy of peri-implant diseases. Established lesions in animals have shown many features in common with those found in human biopsy material. The current review focuses on animal studies, employing different models to induce peri-implant mucositis and peri-implantitis.

Coated vs uncoated implants: bone defect configurations after progressive peri-implantitis in dogs

In this study, hydroxyapatite coated vs uncoated implants were used to evaluate the type and dimensions of bone defects after progressive peri-implantitis in dogs. Thirty-two dental implants with 4 different surfaces-machined (M), sandblasted acid-etched (SA), 1-μm thin sputter hydroxyapatite (HA)-coated (S), and plasma-sprayed HA-coated (P)-were inserted into the mandibles of 4 beagle dogs after extracting all mandibular premolars. Experimental peri-implantitis was induced after 3 months using ligature to allow for plaque accumulation. After 4 months, ligatures were removed and plaque accumulation continued for 5 months (progression period). The open flap surgery demonstrated 3 patterns of peri-implantitis bone defect: (1) Class I defect: represented as circumferential intra-alveolar bone loss; (2) Class II defect: circumferential intra-alveolar defect with supra-alveolar bone loss exposing the implant surface; and (3) Class III defect: represented as circumferential intra-alveolar defect with supra-alveolar bone loss and buccal dehiscence. Class I was the most frequent (62.5%) defect pattern around implant types M, SA, and S; while implant type-P showed a recurring majority of Class II (62.5%). Comparison among the 4 implant groups revealed a significant defect width (DW) in implant type-P relative to other types (P < 0.01). However, no statistically significant differences were noted for defect depth (DD) (P > 0.05). We concluded that the shape and size of peri-implantitis bone defects were influenced by the type and thickness of the HA coat together with the quantity of the available peri-implant bone. Plasma-sprayed HA-coated implants showed larger peri-implant defects than did thin sputter HA-coated implants.

Does implant staging choice affect crestal bone loss?

PURPOSE

The purpose of the present study was to compare the crestal bone loss around implants placed according to either a 1-stage or 2-stage implant installation procedure using a digital subtraction radiography technique.

MATERIALS AND METHODS

In the present randomized clinical trial, screw-shaped tapered implants were inserted in the posterior mandible of patients needing fixed partial dentures. In each edentulous area, according to the randomization table, 1 implant was inserted using a 1-stage procedure (group 1) and 1 was placed using a 2-stage approach (group 2). The implants were temporized with the relined denture after 2 weeks. All implants were functionally loaded with fixed partial dentures after 3 months. Crestal bone loss (primary outcome variable) was measured using a digital subtraction radiography technique. Standardized radiovisiographs were taken after implant insertion, after fixed partial denture installation (3 months after surgery), and after 6 and 12 months of functional loading. The data were analyzed using the Wilcoxon signed ranks test (α = 0.05).

RESULTS

Eleven patients (mean age 46.9 years, 3 women and 8 men) were included in the study. A total of 34 implants were inserted, 17 using a 1-stage protocol and 17 using a 2-stage protocol. Three months after implant placement, the 2-stage implants showed significantly more crestal bone loss (0.65 ± 0.71 mm) than the 1-stage implants (0.41 ± 0.53 mm; P = .02). However, after 6 and 12 months of functional loading, both groups showed comparable changes in bone level (P > .05).

CONCLUSIONS

No differences were found between 1-stage and 2-stage implant placement in crestal bone loss after 1 year of functional loading.

Rank Protein Immunolabeling during Bone-Implant Interface Healing Process

The purpose of this paper was to evaluate the expression of RANK protein during bone-healing process around machined surface implants. Twenty male Wistar rats, 90 days old, after having had a 2 mm diameter and 6 mm long implant inserted in their right tibias, were evaluated at 7, 14, 21, and 42 days after healing. After obtaining the histological samples, slides were subjected to RANK immunostaining reaction. Results were quantitatively evaluated. Results. Immunolabeling analysis showed expressions of RANK in osteoclast and osteoblast lineage cells. The statistical analysis showed an increase in the expression of RANK in osteoblasts at 7 postoperative days and a gradual decrease during the chronology of the healing process demonstrated by mild cellular activity in the final stage (P < .05). Conclusion. RANK immunolabeling was observed especially in osteoclast and osteoblast cells in primary bone during the initial periods of bone-healing/implant interface.

Soft tissue around three different implant types after 1.5 years of functional loading without oral hygiene. A preliminary study in baboons

The purpose of this study was to determine the peri-implant soft tissue dimension (PSD) and peri-implant bone level (BL) of dental implants with different designs and surface modifications after functional loading without oral hygiene. Three types of dental implants were placed in the posterior jaws of adult baboons, three of the same design per quadrant, and fitted with fixed partial dentures. After 1.5 years of functional loading and plaque accumulation, all implants showed severe peri-implant mucositis and comparatively high BL. A histomorphometric evaluation of the sulcus depth (SD), the dimension of the junctional epithelium (JE) and the connective tissue contact (CTC) resulted in no significant differences between the three implant designs, neither in the maxilla nor in the mandible (P>0.05). The sum of SD, JE and CTC forming the PSD was nearly the same in the maxilla (commercially pure titanium, CpTi: 3.5 mm 2.9/4.1 confidence interval (CI); titanium plasma sprayed (TPS): 3.5 mm 2.9/4.2 CI; sand blasted acid-etched (GBAE): 3.2 mm 2.7/3.9 CI) and in the mandible (CpTi: 3.2 mm 2.6/3.8 CI; TPS: 3.2 mm 2.6/3.8 CI; GBAE: 3.2 mm 2.7/3.9 CI; P>0.05). There was no difference in BL around the three implant designs (maxilla: CpTi: 0.9 mm 0.5/1.6 CI; TPS: 0.9 mm 0.5/1.5CI; GBAE: 0.9 mm 0.5/1.6 CI; mandible: CpTi: 0.8 mm 0.5/1.2 CI; TPS: 0.6 mm 0.4/0.9 CI; GBAE: 0.7 mm 0.5/1.1 CI; P>0.05). Overall, the data presented did not show any significant differences in peri-implant soft tissue conditions in baboons. Moreover, plaque accumulation and propagation of peri-implant mucositis after 1.5 years of functional loading was not influenced by implant design and surface modifications in baboons.