Ryan S. B. Lee

Titanium dental implants require both reliable osseointegration and peri‐implant soft tissue seal formation to ensure long‐term success. While osseointegration has been widely studied, strategies to optimize soft tissue healing remain underexplored. In this study, we developed titania nanopore (TNP) implant surfaces functionalized with human primary gingival fibroblasts‐derived microvesicles (hGFs‐MVs) to investigate early peri‐implant soft and hard tissue healing in vivo. hGFs‐MVs were enriched, characterized, and loaded onto TNP implants at 10 ⁹ particles per implant (2 mm × 3 mm) via passive adsorptive loading. Rat first molars were extracted, and implants were placed into healed sockets after 4 weeks. Animals were assigned to TNP or hGFs‐MVs/TNP groups (n = 5–6) and assessed at 1 and 4 weeks by micro‐CT and histology. Cryo‐electron microscopy confirmed the double‐membrane structure of hGFs‐MVs, and in vitro release studies showed peak vesicle release at day 3. Histology revealed early osteoid formation at week 1 and mature mineralized bone by week 4. hGFs‐MVs/TNP implants exhibited significantly higher percentage of bone‐to‐implant contact (BIC%) at 4 weeks. Importantly, the hGFs‐MVs/TNP group showed markedly enhanced soft tissue attachment and mature collagen fibers. These ‘proof‐of‐concept’ findings suggest that hGFs‐MVs‐loaded TNP implants enhance both in vivo osseointegration and soft tissue integration, providing a clinically relevant, cell‐free strategy for improving peri‐implant healing.

Aim: To evaluate the effect of deproteinised bovine bone mineral with collagen (DBBM‐C) grafting on periodontal healing at the distal aspect of the second molar (D2M) during adjacent third molar extraction.Material and Methods: Forty‐two sites in 28 patients were randomly allocated into two groups. The test group (18 sites) received DBBM‐C grafting during extraction, whereas the control group (24 sites) received extraction alone. The patients were reviewed 6 months postoperatively, and the D2M and extraction sites were evaluated by both linear and volumetric cone beam computed tomography measurements.Results: Nine patients dropped out (14 sites) and two patients were excluded (4 sites), leaving a total of 17 patients (24 sites) who were reviewed after 6 months. Both groups showed significant healing when examining the linear measurements (except at the disto‐lingual aspect of the second molar) and the defined volumes of interest. There were, however, no significant differences between the groups in the linear or volumetric outcome analyses.Conclusions: Within the limitations of the study, the use of DBBM‐C during third molar extraction did not improve periodontal healing at the D2M. This trial was registered in April 2020 in the Australian New Zealand Clinical Trials Registry under code ACTRN12620000497909 (https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12620000497909).

Aim: To evaluate the clinical, microbial and cytokine changes following the use of oral azithromycin as an adjunct to non‐surgical subgingival instrumentation (NSI) in stage III/IV, grade C periodontitis through a triple‐blind, parallel‐armed, randomised controlled trial. Material and Methods: A total of 52 patients with stage III/IV grade C periodontitis were randomly allocated to two groups receiving NSI with or without adjunctive azithromycin. The primary outcome was changes in the periodontal inflamed surface area (PISA) values over 12 months, and the secondary outcomes included changes in pocket depth (PD), clinical attachment loss (CAL), percentage of sites with PD of 1–3, 4–5, ≥ 5 and ≥ 6 mm, subgingival periodontal pathogens, cytokine levels and patient‐reported outcomes. Results: At 3 and 12 months, there were no statistically significant differences in the reduction in PISA or other clinical parameters between the groups. At 3 months, the levels of several periodontal pathogens were significantly reduced in the azithromycin group. No significant differences were observed in the levels of periodontal pathogens at 12 months except for Prevotella intermedia. No significant differences were observed for the studied cytokines at 3 and 12 months. Conclusion: The results of this study do not support the use of systemic azithromycin in stage III/IV, grade C periodontitis. Trial Registration: The trial was registered prospectively in the Australia New Zealand Clinical Trial Registry, ACTRN12619000560190. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374699

Objectives: To investigate the effects of alveolar ridge preservation (ARP) on ridge height, sinus pneumatization and the potential need for lateral sinus augmentation following extraction in the posterior maxilla.Materials and Methods: This randomized controlled pilot study included 28 patients requiring extraction in the posterior maxilla with bone height between 6 and 8 mm. The sites were randomly allocated to either unassisted socket healing (Control), ARP with deproteinized bovine bone mineral (DBBM) (Test 1), or collagen‐stabilized DBBM (Test 2) groups. Pre‐ and post‐operative CTs at 4 months were taken to determine changes in ridge heights, sinus volume, and the need for sinus floor elevation (SFE) procedures for cases where the residual mid‐ridge height was < 5 mm. Site‐level analyses for changes in vertical ridge dimensions and sinus volume pre‐ and post‐extraction/ARP were conducted using paired t‐tests. Differences in mean changes in vertical ridge dimensions and sinus volume between the groups were determined using one‐way ANOVA.Results: Significantly greater mean mid‐ridge height reduction occurred in the control group (−2.7 ± 0.9 mm) compared to Test 1 (0.9 ± 3.7 mm) and Test 2 (1.0 ± 2.8 mm) groups (p < .05). No significant changes in mean mid‐ridge height were found in either test groups. Volumetric analysis showed a significantly greater increase in sinus volume in the control group (0.7 ± 0.7 cm³) compared to Test 1 (n = 3, −0.7 ± 0.8 cm³) group (p = .03). 89% of patients in the control group would require lateral window SFE compared to Test 1 (42.8%) and Test 2 (40%) groups.Conclusion: ARP was effective in attenuating height changes in the middle of the ridge and may reduce sinus pneumatization following extraction in the posterior maxilla. This could potentially decrease the need for more invasive sinus augmentation procedures.

Periodontitis is a chronic inflammatory disease caused by dysbiotic biofilms and destructive host immune responses. Extracellular vesicles (EVs) are circulating nanoparticles released by microbes and host cells involved in cell‐to‐cell communication, found in body biofluids, such as saliva and gingival crevicular fluid (GCF). EVs are mainly involved in cell‐to‐cell communication, and may hold promise for diagnostic and therapeutic purposes. Periodontal research has examined the potential involvement of bacterial‐ and host‐cell‐derived EVs in disease pathogenesis, diagnosis, and therapy, but data remains scarce on immune cell‐ or microbial‐derived EVs. In this narrative review, we first provide an overview of the role of microbial and host‐derived EVs on disease pathogenesis. Recent studies reveal that Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans ‐derived outer membrane vesicles (OMVs) can activate inflammatory cytokine release in host cells, while M1 macrophage EVs may contribute to bone loss. Additionally, we summarised current in vitro and pre‐clinical research on the utilisation of immune cell and microbial‐derived EVs as potential therapeutic tools in the context of periodontal treatment. Studies indicate that EVs from M2 macrophages and dendritic cells promote bone regeneration in animal models. While bacterial EVs remain underexplored for periodontal therapy, preliminary research suggests that P. gingivalis OMVs hold promise as vaccine candidates. Finally, we acknowledge the current limitations present in the field of translating immune cell derived EVs and microbial derived EVs in periodontology. It is concluded that microbial and host immune cell‐derived EVs have a role in periodontitis pathogenesis and hence may be useful for studying disease pathophysiology, and as diagnostic and treatment monitoring biomarkers.

Osseointegration is defined as the direct deposition of bone onto biomaterial devices, most commonly composed from titanium, for the purpose of anchoring dental prostheses. The use of autologous platelet concentrates (APC) has the potential to enhance this process by modifying the interface between the host and the surface of the titanium implant. The rationale is to modify the implant surface and implant–bone interface via “biomimicry,” a process whereby the deposition of the host's own proteins and extracellular matrix enhances the biocompatibility of the implant and hence accelerates the osteogenic healing process. This review of the available evidence reporting on the effect of APC on osseointegration explores in vitro laboratory studies of the interaction of APC with different implant surfaces, as well as the in vivo and clinical effects of APC on osseointegration in animal and human studies. The inherent variability associated with using autologous products, namely the unique composition of each individual's blood plasma, as well as the great variety in APC protocols, combination of biomaterials, and clinical/therapeutic application, makes it is difficult to make any firm conclusions about the in vivo and clinical effects of APC on osseointegration. The available evidence suggests that the clinical benefits of adding PRP and the liquid form of L‐PRF (liquid fibrinogen) to any implant surface appear to be limited. The application of L‐PRF membranes in the osteotomy site, however, may produce positive clinical effects at the early stage of healing (up to 6 weeks), by promoting early implant stability and reducing marginal bone loss, although no positive longer term effects were observed. Careful interpretation and cautious conclusions should be drawn from these findings as there were various limitations in methodology. Future studies should focus on better understanding of the influence of APCs on the biomaterial surface and designing controlled preclinical and clinical studies using standardized APC preparation and application protocols.

Background: The aim of this study was to investigate an in vitro dynamic bioreactor model by evaluating the antimicrobial effect of clinically relevant amoxicillin doses on polymicrobial microcosm biofilms derived from subgingival plaque.Methods: Biofilms from pooled subgingival plaque were grown for 108 hours in control and experimental dynamic biofilm reactors. Amoxicillin was subsequently infused into the experimental reactor to simulate the pharmacokinetic profile of a standard 500 mg thrice‐daily dosing regimen over 5 days and biofilms were assessed by live/dead staining, scanning electron microscopy, and quantitative polymerase chain reaction.Results: Following establishment of the oral microcosm biofilms, confocal imaging analysis showed a significant increase in dead bacteria at 8 hours (p = 0.0095), 48 hours (p = 0.0070), 96 hours (p = 0.0140), and 120 hours (p < 0.0001) in the amoxicillin‐treated biofilms compared to the control biofilms. Nevertheless, viable bacteria remained in the center of the biofilm at all timepoints. Significant reductions/elimination in Campylobacter rectus, Tannerella forsythia, Aggregatibacter actinomycetemcomitans, and Peptostreptococcus anaerobius was observed among the amoxicillin‐treated biofilms at the 96 and 120 hour timepoints.Conclusion: A novel in vitro dynamic model of oral microcosm biofilms was effective in modeling the antimicrobial effect of a pharmacokinetically simulated clinically relevant dose of amoxicillin.

Oral biofilms are three‐dimensional (3D) complex entities initiating dental diseases and have been evaluated extensively in the scientific literature using several biofilm models and assessment techniques. The list of biofilm models and assessment techniques may overwhelm a novice biofilm researcher. This narrative review aims to summarize the existing literature on biofilm models and assessment techniques, providing additional information on selecting an appropriate model and corresponding assessment techniques, which may be useful as a guide to the beginner biofilm investigator and as a refresher to experienced researchers. The review addresses previously established 2D models, outlining their advantages and limitations based on the growth environment, availability of nutrients, and the number of bacterial species, while also exploring novel 3D biofilm models. The growth of biofilms on clinically relevant 3D models, particularly melt electrowritten fibrous scaffolds, is discussed with a specific focus that has not been previously reported. Relevant studies on validated oral microcosm models that have recently gaining prominence are summarized. The review analyses the advantages and limitations of biofilm assessment methods, including colony forming unit culture, crystal violet, 2,3‐bis‐(2‐methoxy‐4‐nitro‐5‐sulfophenyl)‐2H‐tetrazolium‐5‐carboxanilide inner salt assays, confocal microscopy, fluorescence in situ hybridization, scanning electron microscopy, quantitative polymerase chain reaction, and next‐generation sequencing. The use of more complex models with advanced assessment methodologies, subject to the availability of equipment/facilities, may help in developing clinically relevant biofilms and answering appropriate research questions.

Soft tissue integration (STI) at the transmucosal level around dental implants is crucial for the long-term success of dental implants. Surface modification of titanium dental implants could be an effective way to enhance peri-implant STI. The present study aimed to investigate the effect of bioinspired lithium (Li)-doped Ti surface on the behaviour of human gingival fibroblasts (HGFs) and oral biofilm in vitro. HGFs were cultured on various Ti surfaces—Li-doped Ti (Li_Ti), NaOH_Ti and micro-rough Ti (Control_Ti)—and were evaluated for viability, adhesion, extracellular matrix protein expression and cytokine secretion. Furthermore, single species bacteria (Staphylococcus aureus) and multi-species oral biofilms from saliva were cultured on each surface and assessed for viability and metabolic activity. The results show that both Li_Ti and NaOH_Ti significantly increased the proliferation of HGFs compared to the control. Fibroblast growth factor-2 (FGF-2) mRNA levels were significantly increased on Li_Ti and NaOH_Ti at day 7. Moreover, Li_Ti upregulated COL-I and fibronectin gene expression compared to the NaOH_Ti. A significant decrease in bacterial metabolic activity was detected for both the Li_Ti and NaOH_Ti surfaces. Together, these results suggest that bioinspired Li-doped Ti promotes HGF bioactivity while suppressing bacterial adhesion and growth. This is of clinical importance regarding STI improvement during the maintenance phase of the dental implant treatment.

Objectives: As biomaterial‐induced modulation of mediators of the immune response may be a potential therapeutic approach to enhance wound healing events, the aim of this study was to delineate the effects of titanium surface modification on macrophage phenotype and function.Material and methods: Rodent bone marrow‐derived macrophages were polarized into M1 and M2 phenotypes and cultured on micro‐rough (SLA) and hydrophilic modified SLA (modSLA) titanium discs. Macrophage phenotype and cytokine secretion were subsequently assessed by immunostaining and ELISA, respectively. Osteoblast gene expression in response to culture in the M1 and M2 macrophage conditioned media was also evaluated over 7 days by RT‐PCR.Results: M1 macrophage culture on the modSLA surface promoted an M2‐like phenotype as demonstrated by marked CD163 protein expression, Arg1 gene expression and the secretion of cytokines that significantly upregulated in osteoblasts the expression of genes associated with the TGF‐ß/BMP signalling pathway and osteogenesis. In comparison, M2 macrophage culture on SLA surface promoted an inflammatory phenotype and cytokine profile that was not conducive for osteogenic gene expression.Conclusions: Macrophages are able to alter or switch their phenotype according to the signals received from the biomaterial surface. A hydrophilic micro‐rough titanium surface topography elicits a macrophage phenotype associated with reduced inflammation and enhanced pro‐osteogenic signalling.