Quality of reporting of experimental research in implant dentistry. Critical aspects in design, outcome assessment and model validation

Are periodontitis and psoriasis associated? A pre-clinical murine model

AIM

To investigate the bidirectional influence between periodontitis and psoriasis, using the respective experimental models of ligature- and imiquimod-induced diseases on murine models.

MATERIALS AND METHODS

Thirty-two C57/BL6J mice were randomly allocated to four experimental groups: control (P- Pso-), ligature-induced periodontitis (P+ Pso-), imiquimod-induced psoriasis (P- Pso+) and periodontitis and psoriasis (P+ Pso+). Samples (maxilla, dorsal skin and blood) were harvested immediately after death. Measures of periodontitis (distance between the cemento-enamel junction and alveolar bone crest [CEJ-ABC] and the number of osteoclasts) and psoriasis (epidermal thickness and infiltrate cell [/0.03mm2]) severity as well as systemic inflammation (IL-6, IL-17A, TNF-α) were collected.

RESULTS

The P+ Pso+ group exhibited the most severe experimental periodontitis and psoriasis, with the highest values of CEJ-ABC, number of osteoclasts, epidermal thickness and infiltrate cells in the dorsal skin, as well as the highest blood cytokine concentration. The P+ Pso- group presented with higher cell infiltrate (/0.03mm2) compared to the control group (p <.05), while the P- Pso+ group showed substantially higher alveolar bone loss (CEJ-ABC) than the control group (p <.05).

CONCLUSIONS

Experimental periodontitis may initiate and maintain psoriasiform skin inflammation and, vice versa, experimental psoriasis may contribute to the onset of periodontitis. In a combined model of the diseases, we propose a bidirectional association between periodontitis and psoriasis via systemic inflammation.

Efficacy of bone ring grafts for the reconstruction of alveolar ridge deficiencies: a systematic review. Part II: animal trials

Background

Bone ring (BR) grafts have been introduced to reconstruct alveolar ridge defects with simultaneous implant placement, but their clinical effectiveness remains undetermined. The aim of the current systematic review was to critically appraise evidence from animal studies regarding the effectiveness of BR grafts in alveolar ridge reconstruction and their variations under different surgical protocols.

Methods

Electronic retrieval of six databases (MEDLINE, Embase, Cochrane Library, ScienceDirect, Web of Science, and Scopus) and citation search until 11 October 2023, for animal studies on bone augmentation employing BR grafts. The outcome variables were total bone area (BA), bone volume (BV), bone-implant contact (BIC), and histology. The protocol was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and prospectively registered with PROSPERO (CRD42023453949).

Results

Ten studies were included in the qualitative analysis according to the screening criteria. Two studies demonstrated favorable bone remodeling and osseointegration of the BR with both the implant and pristine bone. A comparative study between autogenous BRs and allogenic BRs reported a higher percentage of BA and BIC at 4 months of healing, but conflicting data were observed at 8 months. Another study indicated a significant advantage of autogenous BRs over bovine and biphasic ceramic BRs in terms of BA and BIC after 5 weeks. Three studies found that using collagen membranes did not significantly affect BA, BV, or BIC when used simultaneously with autogenous BRs during implant placement. Two studies evaluated one-stage and two-stage implant placement in conjunction with BR grafts, revealing similar levels of BA, BV, and BIC except for differences in total treatment time. Furthermore, one study found that the use of mucogingival junction incision and split-thickness flap significantly reduced the incidence of wound dehiscence compared with conventional incision and flap.

Conclusions

Vertical bone augmentation surgery utilizing BR grafts with one-stage implant placement yielded histological and histomorphometric outcomes comparable to those achieved with two-stage implant placement or the additional application of collagen membrane.

Bone formation in large/moderate gap after immediate implantation in response to different treatments: a pre-clinical study in the canine posterior mandible

OBJECTIVES

This study aims to investigate different treatments on new bone formation around immediate implants in the canine posterior mandible with varying sized mesial-distal gap.

MATERIALS AND METHODS

The 4th premolar and the 1st molar of six Labrador dogs were extracted from the mandible, and 4 dental implants were placed 1 mm below the level of the buccal bone crest. Moderate/large mesial-distal gaps between the implants and the sockets were treated with one of four methods and divided into the following groups: (1) the blank group, (2) the collagen membrane (CM) group, (3) the deproteinized bovine bone mineral (DBBM) group, and (4) the DBBM + CM group. Sequential fluorescent labeling was performed at 4, 8, and 10 weeks after the operation. After 12 weeks, the dogs were euthanized, and specimens were collected for micro-CT scanning and histological analysis.

RESULTS

The survival rate of immediate implant was 100%. Micro-CT showed significant differences in bone mineral density (BMD) and bone volume fraction (BVF) among groups (P = 0.040, P = 0.009); other indicators were not significantly different among groups. Histological analysis showed the proportion of new bone formation and bone-to-implant contact were not significantly different among groups. No significant difference in bone reduction height around dental implant among four groups and varied mesial-distal gap size.

CONCLUSION

Owing to the restricted sample size, this pilot study lacks conclusive findings. Within the limitation, this study demonstrated that although DBBM significantly increase BMD and BVF, the use of DBBM/CM didn't significantly improve bone formation and healing in extraction sockets around the implants in both moderate and large mesial-distal gap.

CLINICAL RELEVANCE

The use of deproteinized bovine bone in conjunction with collagen is a common practice in immediate implantation procedures in the posterior mandible. However, there is a lack of conclusive evidence regarding the timing and circumstances under which they should be employed.

Hard and soft tissue healing around teeth prepared with the biologically oriented preparation technique and restored with provisional crowns: An in vivo experimental investigation

AIM

To evaluate the hard and soft tissues healing around teeth prepared with the biologically oriented preparation technique (BOPT) versus the chamfer technique versus non-prepared teeth.

MATERIALS AND METHODS

Thirty-two teeth in eight beagle dogs were randomly prepared with the BOPT (test = 16) or chamfer (control = 16) techniques and covered with polymethylmethacrylate crowns as provisional restorations. Sixteen negative controls (non-prepared teeth) were also used for comparison. Histological description and histomorphometrical measurements of the periodontal tissues were collected at 4 and 12 weeks in 7 out of 8 dogs, including the soft tissue height and thickness, and the horizontal and vertical bone dimensions.

RESULTS

When compared with negative controls, test and control preparation techniques exhibited a more apical location of the free gingival margin with respect to the cement-enamel junction (∆ = 1.1 mm for both groups at 4 weeks (p < .05), 0.99 mm for the test group (p = .043) and 0.20 mm for control group (p = 1.000) at 12 weeks). There were no significant differences between test and control groups with respect to vertical and horizontal histometric measurements.

CONCLUSIONS

The BOPT and chamfer tooth preparation protocols induced similar qualitative and quantitative changes in the healing of the supra-crestal soft tissue complex, when compared with non-prepared teeth. Despite the limited amount of power, it appeared that differences between the tested preparation techniques were not statistically significant.

A Synthetic Bio-Absorbable Membrane in Guided Bone Regeneration in Dehiscence-Type Defects: An Experimental In Vivo Investigation in Dogs

This study aimed to determine the performance and characteristics of a synthetic barrier membrane of polylactic acid and acetyl butyl citrate (PLAB) for the lateral bone augmentation of peri-implant dehiscence defects (mean height × depth = 3 mm × 1 mm). In eight dogs, three treatment groups were randomly allocated at each chronic peri-implant dehiscence-type defect: (i) a deproteinized bovine bone mineral covered by a synthetic barrier membrane (test group), (ii) a deproteinized bovine bone mineral covered by a natural collagen membrane (positive control), and (iii) a synthetic barrier membrane (negative control). After 4 and 12 weeks of submerged healing, dissected tissue blocks were processed for calcified and decalcified histological analysis. Histometric measurements for tissue and bone width were performed, and bone-to-implant contact and alkaline phosphatase expression where measured. After 4 and 12 weeks of healing, no statistical differences between the groups were observed for the histometric measurements. The expression of alkaline phosphatase was higher in the positive control group after 4 weeks followed by the positive and negative controls (5.25 ± 4.09, 4.46 ± 3.03, and 4.35 ± 2.28%, p > 0.05) and 12 weeks followed by the negative and positive controls (4.3 ± 2.14, 3.21 ± 1.53, and 2.39 ± 1.03%, p > 0.05). Concerning the bone-to-implant contact, after 4 weeks, the test group obtained the highest results (39.54 ± 48.7) vs. (31.24 ± 42.6) and (20.23 ± 36.1), respectively, while after 12 weeks, the positive control group obtained the highest Bone to imaplant contact (BIC) results, followed by the test and negative controls, (35.91 ± 24.9) vs. (18.41 ± 20.5) and (24.3 ± 32.1), respectively; no statistically significant differences were obtained. Within the limitations of the study, new bone formation can be achieved in guided bone regeneration procedures simultaneously with implant placement either with the use of a PLAB membrane or a native collagen membrane, although these differences were not statistically significant.

Restoring the electrical microenvironment using ferroelectric nanocomposite membranes to enhance alveolar ridge regeneration in a mini-pig preclinical model

The maintenance and incremental growth of the alveolar bone at the tooth extraction site, to achieve the required height and width for implant restoration, remains a major clinical challenge. Here, the concept of restoring the electrical microenvironment to improve the effects of alveolar ridge preservation (ARP) was investigated in a mini-pig preclinical model. The endogeneous electrical microenvironment of the dental alveolar socket was recapitulated by fabricating a biomimetic ferroelectric BaTiO₃/poly(vinylidene fluoridetrifluoroethylene) (BTO/P(VDF-TrFE)) non-resorbable nanocomposite membrane polarized by corona poling. The polarized nanocomposite membrane exhibited excellent electrical stability. After implantation with bone grafts and covering with the charged membrane in tooth extraction sites for three months, both the vertical and horizontal dimension resorption of the alveolar ridge were significantly prevented, as assessed by cone beam computed tomography (CBCT) analyses. Micro-CT analysis showed that the charged membrane induced significant enhancement of newly regenerated bone at the tooth extraction sites. Histological analysis further confirmed that the restoration of the electrical microenvironment significantly promoted buccal alveolar bone regeneration and maturation. In addition, the charged membranes can maintain their structural integrity during the entire implantation period and exhibit positive long-term systemic safety, as assessed by preclinical sub-chronic systemic toxicity. These findings thus provide an innovative strategy for restoring the electrical microenvironment to enhance ARP following dentition defect and edentulism, which could further advance prosthodontics implant technology.

Neuroinflammation related to the blood-brain barrier and sphingosine-1-phosphate in a pre-clinical model of periodontal diseases and depression in rats

AIM

To explore the potential mechanisms of neuroinflammation (microglia, blood-brain barrier [BBB] permeability, and the sphingosine-1-phosphate [S1P] pathways) resulting from the association between periodontitis and depression in rats.

MATERIALS AND METHODS

This pre-clinical in vivo experimental study used Wistar rats, in which experimental periodontitis (P) was induced by using oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum. Then, a chronic mild stress (CMS) model was implemented to induce a depressive-like behaviour, resulting in four groups: P with CMS (P+CMS+), P without CMS (P+CMS-), CMS without P (P-CMS+), and control (P-CMS-). After harvesting brain samples, protein/mRNA expression analyses and fluorescence immunohistochemistry were performed in the frontal cortex (FC). Results were analysed by ANOVA.

RESULTS

CMS exposure increased the number of microglia (an indicator of neuroinflammation) in the FC. In the combined model (P+CMS+), there was a decrease in the expression of tight junction proteins (zonula occludens-1 [ZO-1], occludin) and an increase in intercellular and vascular cell adhesion molecules (ICAM-1, VCAM-1) and matrix metalloproteinase 9 (MMP9), suggesting a more severe disruption of the BBB. The enzymes and receptors of S1P were also differentially regulated.

CONCLUSIONS

Microglia, BBB permeability, and S1P pathways could be relevant mechanisms explaining the association between periodontitis and depression.

Preventing Peri-implantitis: The Quest for a Next Generation of Titanium Dental Implants

Titanium and its alloys are frequently the biomaterial of choice for dental implant applications. Although titanium dental implants have been utilized for decades, there are yet unresolved issues pertaining to implant failure. Dental implant failure can arise either through wear and fatigue of the implant itself or peri-implant disease and subsequent host inflammation. In the present report, we provide a comprehensive review of titanium and its alloys in the context of dental implant material, and how surface properties influence the rate of bacterial colonization and peri-implant disease. Details are provided on the various periodontal pathogens implicated in peri-implantitis, their adhesive behavior, and how this relationship is governed by the implant surface properties. Issues of osteointegration and immunomodulation are also discussed in relation to titanium dental implants. Some impediments in the commercial translation for a novel titanium-based dental implant from "bench to bedside" are discussed. Numerous in vitro studies on novel materials, processing techniques, and methodologies performed on dental implants have been highlighted. The present report review that comprehensively compares the in vitro, in vivo, and clinical studies of titanium and its alloys for dental implants.

Evaluation of regeneration after the application of 2 types of deproteinized bovine bone mineral to alveolar bone defects in adult dogs

Purpose

The aim of this study was to evaluate the preclinical results of 2 types of commercially available deproteinized bovine bone mineral (DBBM) when applied to alveolar bone defects in dogs.

Methods

This study was conducted using 6 beagles. Alveolar defects in the mandible were formed and filled with 2 DBBMs produced by a similar procedure. Defects were randomly assigned to be filled using DBBM 1 or 2. All defects were covered with a collagen membrane and had a healing period of 12 weeks. After the dogs were sacrificed, histological, histomorphometric, and linear/volumetric analyses were performed.

Results

Both DBBM groups showed similar histological findings, demonstrating that bone remodeling had occurred and new bone had formed. The residual bone particles were surrounded by newly formed vital bone. In the histomorphometric analysis, the ratio of the area of vital bone and residual bone substitute in DBBM 2 (38.18% and 3.47%, respectively) was higher than that of DBBM 1 (33.74% and 3.41%, respectively), although the difference was not statistically significant. There were also no statistically significant differences between both groups in linear and volumetric analyses using micro-computed tomography scans and digitized images of dental casts.

Conclusions

In the present study, DBBM 1and 2, which were produced by similar processes, showed similar results in histological, histomorphometric, and volumetric analyses. Further studies are needed to identify more specific differences between the 2 DBBMs.

Correlation of Fracture Resistance of Dental Implants and Bite Force in Dogs described in the literature: An In Vitro Study

Dental implants are not routinely used for rehabilitation in veterinary dentistry. For some veterinarians, further studies are necessary to be considered for clinical use in animals. The objective of the present in vitro study was to evaluate static fatigue of dental implants and to correlate that with the bite strength of dogs described in the literature. Sixty implants and abutments were used with the smallest diameter of each brand of implant utilized in the study. Three groups (n  =  20) were created on the basis of the implant diameter, all with external hex connector: 3.30 mm (group 1), 4.0 mm (group 2) and 5.0 mm (group 3). All groups were subjected to quasi-static loading at 30° to the implant's long axis in a universal machine (model AME-5 kN). The mean fracture strength for group 1 was 964 ± 187 N, for group 2 was 1618 ± 149 N and for group 3 was 2595 ± 161 N. Significant differences between the groups with respect to resistance after the load applications were observed (P < .05). The diameter of implants affects the resistance to external forces during the application of non-axial strength (off-axis loading) and must be considered during the planning of rehabilitation to avoid problems.

Effects of hyaluronic acid and deproteinized bovine bone mineral with 10% collagen for ridge preservation in compromised extraction sockets

BACKGROUND

The aim of this study was to evaluate the efficacy of deproteinized bovine bone mineral with 10% collagen (DBBM-C) soaked with hyaluronic acid (HA) for ridge preservation in compromised extraction sockets.

METHODS

Bilateral third, fourth premolars and first molar were hemisected, distal roots were extracted, and then combined endodontic periodontal lesion was induced in the remaining mesial roots. After 4 months, the mesial roots were extracted and the following four treatments were randomly performed: Absorbable collagen sponge (ACS), ACS soaked with HA (ACS+HA), ridge preservation with DBBM-C covered with a collagen membrane (RP), ridge preservation with DBBM-C mixed with HA and covered with a collagen membrane (RP+HA). Animals were sacrificed at 1 and 3 months following treatment. Ridge dimensional changes and bone formation were examined using microcomputed tomography, histology, and histomorphometry.

RESULTS

At 1 month, ridge width was significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups, while the highest proportion of mineralized bone was observed in ACS+HA group. At 3 months, ridge width remained significantly higher in the RP and RP+HA groups than in the ACS and ACS+HA groups. ACS+HA and RP+HA treatments featured the highest proportion of mineralized bone and bone volume density compared with the other groups. No statistical difference was observed between ACS+HA and RP+HA treatments.

CONCLUSIONS

Ridge preservation with the mixture DBBM-C/HA prevented dimensional shrinkage and improved bone formation in compromised extraction sockets at 1 and 3 months.

Pre-Clinical Models in Implant Dentistry: Past, Present, Future

Biomedical research seeks to generate experimental results for translation to clinical settings. In order to improve the transition from bench to bedside, researchers must draw justifiable conclusions based on data from an appropriate model. Animal testing, as a prerequisite to human clinical exposure, is performed in a range of species, from laboratory mice to larger animals (such as dogs or non-human primates). Minipigs appear to be the animal of choice for studying bone surgery around intraoral dental implants. Dog models, well-known in the field of dental implant research, tend now to be used for studies conducted under compromised oral conditions (biofilm). Regarding small animal models, research studies mostly use rodents, with interest in rabbit models declining. Mouse models remain a reference for genetic studies. On the other hand, over the last decade, scientific advances and government guidelines have led to the replacement, reduction, and refinement of the use of all animal models in dental implant research. In new development strategies, some in vivo experiments are being progressively replaced by in vitro or biomaterial approaches. In this review, we summarize the key information on the animal models currently available for dental implant research and highlight (i) the pros and cons of each type, (ii) new levels of decisional procedures regarding study objectives, and (iii) the outlook for animal research, discussing possible non-animal options.

Hard and soft tissue healing around implants with a modified implant neck configuration: An experimental in vivo preclinical investigation

Objectives

Evaluate the dimensions and morphology of peri‐implant tissues around a modified dental implant designed with tissue level connection and a convergent transmucosal neck, when compared with a conventional bone level implant connected to a cylindrical machined titanium abutment.

Material and methods

Eight experimental animals were used for this in vivo investigation, in whom 16 test and 16 control implants were placed following a random allocation sequence. The following histological outcomes at 4 and 12 weeks were evaluated: morphology of peri‐implant tissues, the soft tissue height and thickness, the horizontal and vertical bone remodeling, and the bone to implant contact (BIC).

Results

In both early (4 weeks) and late (12 weeks) healing times, there were no statistically significant differences between test and control implants, with respect to the overall height and thickness of the peri‐implant hard and soft tissues. There was a tendency toward a more coronal free gingival margin (I‐FGM) at the buccal aspect of test when compared to control implants (at 4 weeks, difference of 0.97 mm (p = .572) and 0.30 mm (p = 1.000) at 12 weeks). Similarly, there was a tendency toward a more coronal position of the first bone to implant contact (I‐B) at the buccal aspect of test as compared to control implants (1.08 mm (p = 0.174) at 4 weeks and 0.83 mm (p = 0.724) at 12 weeks).

Conclusions

Hard and soft tissue healing occurred at both implant types with no statistically significant differences. Test implants tended to present a more coronal gingival margin (FGM) and first bone to implant contact (B).

Cell-Based Therapy for Tooth Replantation Following Avulsion: A Systematic Review

The management of avulsed teeth undergoing delayed replantation remains a clinical challenge as there are currently no effective interventions that can improve periodontal healing and prevent replacement root resorption. While several preclinical studies have reported varied success using cell-based tissue engineering to improve periodontal healing, a consensus is required before further clinical translation. Therefore, this systematic review seeks to evaluate the efficacy of cell-based therapy in promoting periodontal healing following delayed replantation in animal models. MEDLINE (PubMed) and Embase were searched on September 27, 2020. Ten studies involving rodent and dog models met the inclusion criteria. Cell sources included gingiva, periodontal ligament (PDL), bone marrow, and adipose tissues. Generally, cell-based therapy had increased the proportion of root surfaces displaying periodontal healing and concomitantly reduced the proportion presenting with replacement root resorption and ankylosis. The best outcomes were observed following treatment with PDL-derived cells of various potency. Future preclinical studies will benefit from adopting measures to minimize bias during the conduct of animal experiments and the standardization of the outcome measures reporting. This will facilitate future reviews with possible pooling of results in the form of meta-analyses, allowing a consensus to be obtained from the literature. In addition, further research will be required to shed light on the implications of using allogeneic cells as well as the optimization of cell delivery protocols. The findings of this systematic review demonstrated the therapeutic potential of certain cell-based therapies in promoting periodontal healing following delayed replantation, thus highlighting their prospective clinical benefits and translational value.

Immunohistochemical characteristics of lateral bone augmentation using different biomaterials around chronic peri-implant dehiscence defects: An experimental in vivo study

AIM

To investigate the immunohistochemical characteristics of a highly porous synthetic bone substitute and a cross-linked collagen membrane for guided bone regeneration.

METHODS

Three experimental groups were randomly allocated at chronic peri-implant dehiscence defect in 8 beagle dogs: (i) biphasic calcium phosphate covered by a cross-linked collagen membrane (test group), (ii) deproteinized bovine bone mineral covered by a natural collagen membrane (positive control) and (iii) no treatment (negative control). After 8 and 16 weeks of submerged healing, dissected tissue blocks were processed for immunohistochemical analysis. Seven antibodies were used to detect the remaining osteogenic and angiogenic potential, and quantitative immunohistochemical analysis was done by software.

RESULTS

The antigen reactivity of alkaline phosphatase was significantly higher in the test group compared to the positive and negative controls, and it maintained till 16 weeks. The intensity of osteocalcin was significantly higher in the positive control at 8 weeks than the other groups, but significantly decreased at 16 weeks and no difference was found between the groups. A significant large number of TRAP-positive cells were observed in the test group mainly around the remaining particles at 16 weeks. The angiogenic potential was comparable between the groups showing no difference in the expression of transglutaminase II and vascular endothelial growth factor.

CONCLUSION

Guided bone regeneration combining a highly porous biphasic calcium phosphate synthetic biomaterial with a crosslinked collagen membrane, resulted in extended osteogenic potential when compared to the combination of deproteinized bovine bone mineral and a native collagen membrane.

Periodontal diseases and depression: A pre-clinical in vivo study

AIM

To analyse, through a pre-clinical in vivo model, the possible mechanisms linking depression and periodontitis at behavioural, microbiological and molecular levels.

MATERIALS AND METHODS

Periodontitis (P) was induced in Wistar:Han rats (oral gavages with Porphyromonas gingivalis and Fusobacterium nucleatum) during 12 weeks, followed by a 3-week period of Chronic Mild Stress (CMS) induction. Four groups (n = 12 rats/group) were obtained: periodontitis and CMS (P+CMS+); periodontitis without CMS; CMS without periodontitis; and control. Periodontal clinical variables, alveolar bone levels (ABL), depressive-like behaviour, microbial counts and expression of inflammatory mediators in plasma and brain frontal cortex (FC), were measured. ANOVA tests were applied.

RESULTS

The highest values for ABL occurred in the P+CMS+ group, which also presented the highest expression of pro-inflammatory mediators (TNF-α, IL-1β and NF-kB) in frontal cortex, related to the lipoprotein APOA1-mediated transport of bacterial lipopolysaccharide to the brain and the detection of F. nucleatum in the brain parenchyma. A dysregulation of the hypothalamic-pituitary-adrenal stress axis, reflected by the increase in plasma corticosterone and glucocorticoid receptor levels in FC, was also found in this group.

CONCLUSIONS

Neuroinflammation induced by F. nucleatum (through a leaky mouth) might act as the linking mechanism between periodontal diseases and depression.

Hard tissue volumetric and soft tissue contour linear changes at implants with different surface characteristics after experimentally induced peri-implantitis: an experimental in vivo investigation

OBJECTIVE

To evaluate the hard tissue volumetric and soft tissue contour linear changes in implants with two different implant surface characteristics after a ligature-induced peri-implantitis.

MATERIAL AND METHODS

In eight beagle dogs, implants with the same size and diameter but distinct surface characteristics were placed in the healed mandibular sites. Test implants had an external monolayer of multi-phosphonate molecules (B+), while control implants were identical but without the phosphonate-rich surface. Once the implants were osseointegrated, oral hygiene was interrupted and peri-implantitis was induced by placing subgingival ligatures. After 16 weeks, the ligatures were removed and peri-implantitis progressed spontaneously. Bone to implant contact (BIC) and bone loss (BL) were assessed three-dimensionally with Micro-Ct (μCT). Dental casts were optically scanned and the obtained digitalized standard tessellation language (STL) images were used to assess the soft tissue vertical and horizontal contour linear changes.

RESULTS

Reduction of the three-dimensional BIC percentage during the induction and progression phases of the experimental peri-implantitis was similar for both the experimental and control implants, without statistically significant differences between them. Soft tissue analysis revealed for both implant groups an increase in horizontal dimension after the induction of peri-implantitis, followed by a decrease after the spontaneous progression period. In the vertical dimension, a soft tissue dehiscence was observed in both groups, being more pronounced at the buccal aspect.

CONCLUSIONS

The added phosphonate-rich surface did not provide a more resistant environment against experimental peri-implantitis, when assessed by the changes in bone volume and soft tissue contours.

CLINICAL RELEVANCE

Ligature-induced peri-implantitis is a validated model to study the tissue changes occurring during peri-implantitis. It was hypothesized that a stronger osseointegration mediated by the chemical bond of a phosphonate-rich implant surface would develop an environment more resistant to the inflammatory changes occurring after experimental peri-implantitis. These results, however, indicate that the hard and soft tissue destructive changes occurring at both the induction and progression phases of experimental peri-implantitis were not influenced by the quality of osseointegration.

Hard and soft tissue changes after guided bone regeneration using two different barrier membranes: an experimental in vivo investigation

OBJECTIVE

To assess the contour and volumetric changes of hard and soft tissues after guided bone regeneration (GBR) using two types of barrier membranes together with a xenogeneic bone substitute in dehiscence-type defects around dental implants.

MATERIAL AND METHODS

In 8 Beagle dogs, after tooth extraction, two-wall chronified bone defects were developed. Then, implants were placed with a buccal dehiscence defect that was treated with GBR using randomly: (i) deproteinized bovine bone mineral (DBBM) covered by a synthetic polylactic membrane (test group), (ii) DBBM plus a porcine natural collagen membrane (positive control) and (iii) defect only covered by the synthetic membrane (negative control group). Outcomes were evaluated at 4 and 12 weeks. Micro-CT was used to evaluate the hard tissue volumetric changes and STL files from digitized cast models were used to measure the soft tissues contour linear changes.

RESULTS

Test and positive control groups were superior in terms of volume gain and contour changes when compared with the negative control. Soft tissue changes showed at 4 weeks statistically significant superiority for test and positive control groups compared with negative control. After 12 weeks, the results were superior for test and positive control groups but not statistically significant, although, with a lesser magnitude, the negative control group exhibited gains in both, soft and hard tissues.

CONCLUSIONS

Both types of membranes (collagen and synthetic) attained similar outcomes, in terms of hard tissue volume gain and soft tissue contours when used in combination with DBBM CLINICAL RELEVANCE: Synthetic membranes were a valid alternative to the "gold standard" natural collagen membrane for treating dehiscence-type defects around dental implants when used with a xenogeneic bone substitute scaffold.

Volume stability of the augmented sinus using a collagenated bovine bone mineral grafted in case of a perforated Schneiderian membrane: An experimental study in rabbits

OBJECTIVES

To determine the volume stability of a sinus augmented with a collagenated bovine bone mineral (CBBM) in case of an intact or perforated Schneiderian membrane (SM).

MATERIALS AND METHODS

A bilateral sinus augmentation procedure was performed in eight rabbits. The SM was intentionally perforated in one side (SMP group), while it remained intact in contra-lateral side (control group) and the same amount of CBBM was then grafted. At 12 weeks, the animals were euthanized for radiographic and histomorphometric analyses.

RESULTS

The augmented volume did not differ significantly between the two groups: 262.2 ± 32.1 mm³ in SMP group and 261.9 ± 48.5 mm³ in the control group (p = .959). There was no significant difference in the total augmented area: 24.7 ± 5.2 mm² in SMP group and 23.2 ± 2.9 mm² in the control group (p = .773). The areas of newly formed bone also did not differ significantly between the two groups, but was significantly lower at the centre of the augmented region than in the region of the surgical window in both groups (p < .05).

CONCLUSION

A perforation of the SM in a rabbit model does neither impact the augmented volume nor new bone formation following grafting of the sinus with a CBBM.

Alveolar crest contour changes after guided bone regeneration using different biomaterials: an experimental in vivo investigation

OBJECTIVE

To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects around implants.

MATERIAL AND METHODS

Chronic alveolar ridge defects were created bilaterally in the mandible of eight Beagle dogs. Once implants were placed, three treatment groups were randomly allocated to each peri-implant dehiscence defect: (i) test group received a bone substitute composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) covered by a cross-linked collagen membrane, (ii) positive control group with placement of deproteinized bovine bone mineral (DBBM) plus a porcine natural collagen membrane, and (iii) a negative control with no treatment. Two healing periods (8 and 16 weeks) were evaluated. Dental casts were optically scanned, the obtained files were uploaded into an image analysis software and superimposed to evaluate the linear changes.

RESULTS

In both healing periods, the gains in linear contours were higher in the test group and at the intermediate level (3 mm below the gingival margin). While at 8 weeks, no significant differences were found between the groups; at 16 weeks, the test and positive control groups demonstrated significant gains in contour compared with negative control.

CONCLUSIONS

GBR using different biomaterials significantly increased the buccal contours of the alveolar crest when used at dehiscence defects around dental implants.

CLINICAL RELEVANCE

Particulate highly porous synthetic bone substitute and a cross-linked collagen membrane demonstrated similar outcomes in terms of contour augmentation when compared to bovine xenograft (DBBM) and a collagen membrane.

Osseodensification -- A systematic review and qualitative analysis of published literature

The recently introduced technique of osseodensification for dental implant involves the use of special drills (Densah) run in a counter-clockwise direction at the osteotomy site. It is claimed that this causes expansion of the osteotomy site, and increases density of the bone in immediate vicinity of the osteotomy. We reviewed published papers on the primary stability attained using this drilling technique. As a secondary finding, the bone to implant contact (BIC) and the bone area fraction occupancy (BAF) was also compared between the conventional drilling protocol and the osseodensification protocol, among these articles. A Systematic search was performed in PubMed-Medline, Embase and Google Scholar for clinical/animal studies up to November 2018. A total of 12 articles, from a database of 132 articles, consisting of 8 animal histologic studies, 2 human based clinical studies, 1 case series and 1 case report were assessed. 10/12 articles measured the insertion torque values, 7/12 articles measured the BIC and 6/12 articles estimated the BAF between the two techniques. Quality assessment of 8 studies performed using ARRIVE guidelines showed that 6/8 studies had a high score. An average increase in the insertion torque, BIC and BAF was noted in the osseodensification group as compared to the conventional drilling group. Since most of these studies are non-clinical, it can be inferred that osseodensification is an efficient way to enhance primary stability of implants in low density bone in an animal model. However, extrapolation to long term clinical success cannot be ascertained until further evidence becomes available.

The reporting quality of acupuncture for neurogenesis in experimental ischemic stroke study

Background

There is increasing evidence demonstrating the highly inadequate reporting of preclinical research in multiple scientific publications. The purpose of this study is to systematically investigate the reporting quality of acupuncture for neurogenesis in animal models of acute ischemic stroke.

Methods

We searched eight databases, including PubMed, EMBASE, CINAHL, AMED, Chinese National Knowledge Infrastructure, VIP information database, Wanfang data Information Site, and Chinese Biomedical Literature Database. The methodological quality of included studies was assessed by using the CAMARADES 10-item checklist. The STRICTA statement was modified to gear to animal acupuncture research. The reporting quality was assessed according to the ARRIVE guidelines and the modified STRICTA statement. Data were analyzed with descriptive statistics.

Results

Ultimately, 44 studies containing 2,411 subjects were identified. The overall compliance with the CAMARADES 10-item checklist has a mean of 4.3. The reporting quality indicated that the overall compliance with ARRIVE guidelines has a mean of 59.9% and with the modified STRICTA statement a mean of 71.8%. The findings suggest that the reporting quality of acupuncture for preclinical stroke was generally poor.

Conclusions

Full compliance with ARRIVE guidelines and/or modified STRICTA statement in designing, conducting and reporting preclinical acupuncture research is urgently needed in the future.

Biomodification of compromised extraction sockets using hyaluronic acid and rhBMP-2: An experimental study in dogs

BACKGROUND

This experimental study aims to evaluate the effect of hyaluronic acid on healing of infected extraction sockets compared with recombinant human bone morphogenetic protein-2 (rhBMP-2).

METHODS

Both third and fourth mandibular premolars of six beagle dogs were hemisected, and the distal roots were extracted at baseline. Subsequently, combined endodontic-periodontic lesions were induced at the remaining mesial roots. After 4 months, the mesial roots on both sides of the mandible were removed. Four sockets per dog were randomly allocated to four groups: Group 1, Control; Group 2, only absorbable collagen sponge (ACS: carrier); Group 3, 1% hyaluronic acid (HA) gel + ACS; and Group 4, rhBMP-2 + ACS. After 3 months of healing, the dogs were euthanized for microcomputed tomography and histologic analysis.

RESULTS

After the lesion induction period (4 months), communication between the periodontal lesion and endodontic periapical lesion was observed at all remaining mesial roots. Alveolar bone overgrowth was observed in groups 3 and 4, but bone volume density was not significantly different among all groups. At the crestal portion, mineralization, and osteocalcin expression were higher in groups 3 and 4 than in groups 1 and 2.

CONCLUSION

Treatment with HA can promote bone formation and improve the wound healing rate comparable to rhBMP-2 in infected extraction sockets.

Endo-sinus bone formation after transalveolar sinus floor elevation without grafting with simultaneous implant placement: Histological and histomorphometric assessment in a dog model

AIM

To evaluate endo-sinus new bone formation and implant osseointegration after transalveolar sinus floor elevation (TSFE) and simultaneous implant placement without any grafting materials and to investigate the influence of implant surface modification on bone healing process under this circumstance.

MATERIALS AND METHODS

Transalveolar sinus floor elevation and simultaneous implant placement were conducted bilaterally on 12 Labrador dogs. No grafting materials were used during surgery. Implants with two different surfaces (SLA and SLActive) were placed in a split-mouth design. The animals were sacrificed 4, 8 and 24 weeks after surgery for histological and histomorphometric assessments. Bone-to-implant contact (BIC%), alveolar bone height (ABH) and the percentages of mineralized bone (MB%) in the area of interest were analysed. The probing depth (PD) and bleeding on probing (BOP) were also assessed to describe peri-implant health conditions.

RESULTS

Sprouts of new bone in direct contact with implant surface were seen in the elevated area at every time point. Newly formed woven bone under sinus membrane was visible. SLActive implants exhibited favourable results compared with SLA implants regarding ABH at 4 weeks and BIC% at 4 and 8 weeks. Sites with BOP positive could be observed in both groups at any time point. No newly formed bone can be found on the implant apex with either SLA or SLActive surfaces at any time point.

CONCLUSIONS

Spontaneous new bone formation from the parent bone walls could be observed after TFE without any grafting materials. No clear evidence of bone formation from the Schneiderian membrane could be found. Even though there were trends for quicker bone response of SLActive implants, this study failed to show the absolute advantage of SLActive in achieving endo-sinus bone formation.

Anti-resorptive effect of pamidronate on extraction socket wall in dogs

AIM

The aim of this experimental in vivo investigation was to assess the anti-resorptive effect of low concentration pamidronate on the buccal plate in fresh extraction sockets.

MATERIALS AND METHODS

The distal roots of the third premolars were extracted bilaterally in six dogs. A collagen matrix loaded with either pamidronate (test group) or saline (control group) was positioned on the outer surface of buccal bone immediately after tooth extraction and subsequently covered with a coronally advanced flap. Histological and histomorphometric outcomes were evaluated 12 weeks later.

RESULTS

The mean vertical distance between the buccal and lingual bone crest differed significantly between the test and control groups (0.52 ± 0.43 and 2.21 ± 1.15 mm, respectively; p = .037). The width of the buccal bone 1 mm below the crest was significantly wider in the test group than the control group (4.68 ± 0.68 vs. 3.44 ± 0.60 mm, p < .001).

CONCLUSIONS

Local application of pamidronate onto a collagen matrix may reduce the dimensional changes of the buccal bone plate both vertically and horizontally.

Contour changes after guided bone regeneration of large non-contained mandibular buccal bone defects using deproteinized bovine bone mineral and a porcine-derived collagen membrane: an experimental in vivo investigation

OBJECTIVE

The objective of this study was to evaluate soft tissue contour changes after three different regenerative therapies in chronic ridge defects.

MATERIAL AND METHODS

Buccal bone defects were created in the mandible of nine beagle dogs. Augmentation procedures were performed 3 months later using a bone replacement graft (BRG), resorbable collagen membrane (MBG), or a combination of both procedures (CBG). Silicone impressions were taken before tooth extraction (T1), before the augmentation procedure (T2), and 3 months after the regenerative surgeries (T3). Casts were optically scanned and stereolithography files were superimposed to analyze the horizontal changes in ridge contours.

RESULTS

After defect creation, most part of the horizontal changes occurred 4 and 6 mm below the gingival margin. In the mesial defect (D1) at T3, the mean horizontal gain in MBG amounted to 0.47 ± 0.34 mm, 0.79 ± 0.67 mm in the BRG, and 0.87 ± 0.69 mm for the CBG. In the middle defect (D2), the mean changes for the MBG were 0.11 ± 0.31, 1.01 ± 0.91 for the BRG, and 0.98 ± 0.49 for the CBG. The mean changes in the distal defect (D3) amounted to 0.24 ± 0.72 for the MBG, 1.04 ± 0.92 for the BRG, and 0.86 ± 0.56 for the CBG. The differences reached significance in all defects for the comparison MBG-BRG and MBG-CBG, while similar parameters were observed for the comparison BRG-CBG.

CONCLUSION

BRG and CBG were equally effective and superior to MBG in increasing the horizontal tissue contours. The augmentation seldom reached the values before extraction.

CLINICAL RELEVANCE

Scaffolding materials are needed for contour augmentation when using resorbable collagen membranes.

The Mechanical Properties and Biometrical Effect of 3D Preformed Titanium Membrane for Guided Bone Regeneration on Alveolar Bone Defect

The purpose of this study is to evaluate the effect of three-dimensional preformed titanium membrane (3D-PFTM) to enhance mechanical properties and ability of bone regeneration on the peri-implant bone defect. 3D-PFTMs by new mechanically compressive molding technology and manually shaped- (MS-) PFTMs by hand manipulation were applied in artificial peri-implant bone defect model for static compressive load test and cyclic fatigue load test. In 12 implants installed in the mandibular of three beagle dogs, six 3D-PFTMs, and six collagen membranes (CM) randomly were applied to 2.5 mm peri-implant buccal bone defect with particulate bone graft materials for guided bone regeneration (GBR). The 3D-PFTM group showed about 7.4 times higher mechanical stiffness and 5 times higher fatigue resistance than the MS-PFTM group. The levels of the new bone area (NBA, %), the bone-to-implant contact (BIC, %), distance from the new bone to the old bone (NB-OB, %), and distance from the osseointegration to the old bone (OI-OB, %) were significantly higher in the 3D-PFTM group than the CM group (p < .001). It was verified that the 3D-PFTM increased mechanical properties which were effective in supporting the space maintenance ability and stabilizing the particulate bone grafts, which led to highly efficient bone regeneration.

Current Evidence on the Socket-Shield Technique: A Systematic Review

The recently popularized socket-shield technique involves intentional retention of a section of the remnant root at the time of immediate implant placement, thereby preserving the buccal/proximal bone from resorption. The objective of this systematic review was to assess the literature available on the socket-shield technique and weigh its biological plausibility and long-term clinical prognosis. A systematic search was performed on PubMed-Medline, Embase, Web of Knowledge, Google Scholar, and Cochrane Central for clinical/animal studies from January 1970 to April 2017. Twenty-three studies were assessed: 1 clinical case-control study, 4 animal histological reports, 1 clinical abstract, and 17+2* case reports. Eighteen out of the 23 studies had a duration of ≤12 months. A quality assessment of 5 studies (4 animal histologic and 1 clinical case-control) performed using the modified Animal Research: Reporting of In Vivo Experiments guidelines revealed that 4/5 studies had low scores. Fifty-eight out of 70 (82.86%) implants from 4 animal histological studies had complications; buccal/crestal bone loss (54.55%) and failure of osseointegration (27.27%) were the most common. Thirty-three out of 136 (24.26%) implants from 19+2 (2 studies had both histologic and clinical components, which are assessed separately) clinical studies had complications; buccal/crestal bone loss (78.78%) and shield exposure/failure (12.12%) were the most common. Other complications recorded were periodontal ligament and cementum formation on implant surfaces, pocket formation, inflammation, mucositis, and peri-implantitis. However, some clinical reports indicated stable results at 12 months. It would be difficult to predict the long-term success of this technique until high-quality evidence becomes available. A video abstract is available for viewing at https://youtu.be/lNMeUxj2XPA?list=PLvRxNhB9EJqbqjcYMbwKbwi8Xpbb0YuHI .

Root coverage using porcine collagen matrix with fibroblast growth factor-2: a pilot study in dogs

AIM

The aim of this study was to evaluate the effect of fibroblast growth factor-2 (FGF-2) in combination with porcine collagen matrix (CM) for coverage of gingival recession defects in dogs.

MATERIALS AND METHODS

In five male mongrel dogs, labial gingival recession defects were surgically created in the lower-third incisors bilaterally. The defects were randomly assigned to the CM/FGF-2 group (experimental) or the CM-only group (control). Standardized clinical photographs and silicone impressions were taken at 4 and 16 weeks of healing to calculate the remaining recession area. The dogs were euthanized after 16 weeks for histometric analysis.

RESULTS

At 4 weeks, the recession area of the CM/FGF-2 group was significantly smaller than that of the CM-only group (2.55 ± 0.66 and 4.92 ± 1.05 mm² , respectively, p = 0.023), However, no significant difference was observed at 16 weeks. Histometrically, the amount of newly formed cementum was larger in the CM/FGF-2 group than in the CM-only group at 16 weeks (1.55 ± 0.44 and 0.88 ± 0.51 mm, respectively, p = 0.024).

CONCLUSIONS

The combination of CM/FGF-2 may enhance the early wound healing and may promote cementum formation to a higher extent compared to the use of CM alone.

Adherence to ARRIVE Guidelines in Chinese Journal Reports on Neoplasms in Animals

BACKGROUND

The Animals in Research: Reporting In Vivo Experiments (ARRIVE) guidelines were published in 2010 with the aim of improving the quality of studies involving animals. However, how well Chinese studies involving animal neoplasms adhere to these guidelines has not been assessed.

OBJECTIVE

To evaluate the reporting quality of such experiments published between 2010 and 2012 in Chinese journals with support from the National Natural Science Foundation of China.

METHODS

We searched the Chinese Science Citation and Chinese Journal Full-Text Databases for articles published between 2010 and 2012 involving neoplasms in animals. The data were extracted into pre-prepared forms. Reporting quality was assessed using the ARRIVE checklist-39 items plus information on blinding.

RESULTS

Three hundred and ninety-six animal studies were included in the analysis: 127 studies published in 2010, 140 studies published in 2011, and 129 studies published in 2012. The range of ARRIVE score is from 12 to 27 with a maximum possible score of 40. Studies published in 2012 (P = 0.012), 2011 (P = 0.015), 2010, July~Dec (P<0.017) had a significantly larger ARRIVE checklist score than those published in Jan.~June, 2010, respectively.

CONCLUSIONS

Experiments involving neoplasms in animals published in Chinese journals generally have not comprehensively reported the information recommended by the ARRIVE guidelines. We strongly recommend that researchers conducting such studies report this information.

Effects of cisplatin chemotherapy on the osseointegration of titanium implants

PURPOSE

The effect of chemotherapy on the osseointegration of dental implants has received less interest compared with radiotherapy. Thus, the aim of the current study was to investigate the effect of cisplatin chemotherapy on the osseointegration of dental implants in a rabbit model.

MATERIALS AND METHODS

Sixteen New Zealand White rabbits were randomly assigned to two groups of treatment of either cisplatin at 2.5 mg/kg/week for 4 weeks (n = 8) or placebo (n = 8), in which the first dose was administered 2 days prior to the surgical procedure. Each rabbit received one titanium dental implant inserted in the right distal femoral condyle. Four rabbits from each group were sacrificed 4 and 8 weeks after implant insertion. Osseointegration of the dental implants was analysed using micro-computed tomography and histomorphometric evaluation.

RESULTS

Analysis of micro-computed tomography data and histomorphometric data showed that the osseointegration parameters, including the ratio of bone volume to total volume (BV/TV) and bone-implant contact (BIC%) for the cisplatin group, were significantly lower compared to the control group at 4 and 8 weeks. (P ≤ 0.05).

CONCLUSION

Cisplatin chemotherapy had a negative effect on the osseointegration of dental implants when inserted throughout the chemotherapeutic regimens in a rabbit model.

Endogenous opioid antagonism in physiological experimental pain models: a systematic review

Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double-blind studies using ʻinhibitoryʼ or ʻsensitizingʼ, physiological test paradigms in healthy human subjects. The databases PubMed and Embase were searched according to predefined criteria. Out of a total of 2,142 records, 63 studies (1,477 subjects [male/female ratio = 1.5]) were considered relevant. Twenty-five studies utilized ʻinhibitoryʼ test paradigms (ITP) and 38 studies utilized ʻsensitizingʼ test paradigms (STP). The ITP-studies were characterized as conditioning modulation models (22 studies) and repetitive transcranial magnetic stimulation models (rTMS; 3 studies), and, the STP-studies as secondary hyperalgesia models (6 studies), ʻpainʼ models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and rTMS. In the remaining 14 conditioning modulation studies either absence of effects or ambiguous effects by MOR-antagonists, were observed. In the STP-studies, no effect of the opioid-blockade could be demonstrated in 5 out of 6 secondary hyperalgesia studies. The direction of MOR-antagonist dependent effects upon pain ratings, threshold assessments and somatosensory evoked potentials (SSEP), did not appear consistent in 28 out of 32 ʻpainʼ model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect, presumably mediated by an EOS-dependent mechanisms of analgesia and hyperalgesia.

Wound models for periodontal and bone regeneration: the role of biologic research

The ultimate goals of periodontal therapy remain the complete regeneration of those periodontal tissues lost to the destructive inflammatory-immune response, or to trauma, with tissues that possess the same structure and function, and the re-establishment of a sustainable health-promoting biofilm from one characterized by dysbiosis. This volume of Periodontology 2000 discusses the multiple facets of a transition from therapeutic empiricism during the late 1960s, toward regenerative therapies, which is founded on a clearer understanding of the biophysiology of normal structure and function. This introductory article provides an overview on the requirements of appropriate in vitro laboratory models (e.g. cell culture), of preclinical (i.e. animal) models and of human studies for periodontal wound and bone repair. Laboratory studies may provide valuable fundamental insights into basic mechanisms involved in wound repair and regeneration but also suffer from a unidimensional and simplistic approach that does not account for the complexities of the in vivo situation, in which multiple cell types and interactions all contribute to definitive outcomes. Therefore, such laboratory studies require validatory research, employing preclinical models specifically designed to demonstrate proof-of-concept efficacy, preliminary safety and adaptation to human disease scenarios. Small animal models provide the most economic and logistically feasible preliminary approaches but the outcomes do not necessarily translate to larger animal or human models. The advantages and limitations of all periodontal-regeneration models need to be carefully considered when planning investigations to ensure that the optimal design is adopted to answer the specific research question posed. Future challenges lie in the areas of stem cell research, scaffold designs, cell delivery and choice of growth factors, along with research to ensure appropriate gingival coverage in order to prevent gingival recession during the healing phase.

Key aspects on the use of bone substitutes for bone regeneration of edentulous ridges

OBJECTIVES

To review the histological and clinical outcomes of the use of bone substitues in different oral bone regenerative procedures: socket preservation, immediate implant placement, lateral and vertical bone augmentation.

METHODS

Histological animal studies and clinical trials regarding the performances of bone substitutes, either allogenic, xenogeneic or alloplastic, have been evaluated. Different procedures examined separately and evidence-based results were provided.

RESULTS

The use of deproteinized bovine bone mineral (DBBM) seems to be effective most clinical indications, due to their osteoconductivity, space maintenance characteristics and slow resorption. The combination of Hydroxyapatite and Beta Tricalcium Phospate (HA/TCP) has also reported similar histological evidence and clinical outcomes. The use of autogenous block grafts is still the method of choice in clinical situations in need of vertical bone augmentation.

CONCLUSIONS

The use of bone substitutes is the standard of therapy in current modalities of lateral bone augmentation, mainly when used in conjunction with implant placement.

Orthodontics treatments for managing obstructive sleep apnea syndrome in children: A systematic review and meta-analysis

A small maxilla and/or mandible may predispose children to sleep-disordered breathing, which is a continuum of severity from snoring to obstructive sleep apnea. Preliminary studies have suggested that orthodontic treatments, such as orthopedic mandibular advancement or rapid maxillary expansion, may be effective treatments. The aim is to investigate the efficacy of orthopedic mandibular advancement and/or rapid maxillary expansion in the treatment of pediatric obstructive sleep apnea. Pubmed, Medline, Embase, and Internet were searched for eligible studies published until April 2014. Articles with adequate data were selected for the meta-analysis; other articles were reported in the qualitative assessment. Data extraction was conducted by two independent authors. A total of 58 studies were identified. Only eight studies were included in the review; of these, six were included in the meta-analysis. The research yielded only a small number of studies. Consequently, any conclusions from the pooled diagnostic parameters and their interpretation should be treated carefully. Although the included studies were limited, these orthodontic treatments may be effective in managing pediatric snoring and obstructive sleep apnea. Other related health outcomes, such as neurocognitive and cardiovascular functions have not yet been systematically addressed. More studies are needed with larger sample size, specific inclusion and exclusion criteria and standardized data reporting to help establish guidelines for the orthodontic treatment of pediatric obstructive sleep apnea.

Osseointegration of titanium implants functionalised with phosphoserine-tethered poly(epsilon-lysine) dendrons: a comparative study with traditional surface treatments in sheep

The aim of this study was to analyse the osseointegrative potential of phosphoserine-tethered dendrons when applied as surface functionalisation molecules on titanium implants in a sheep model after 2 and 8 weeks of implantation. Uncoated and dendron-coated implants were implanted in six sheep. Sandblasted and etched (SE) or porous additive manufactured (AM) implants with and without additional dendron functionalisation (SE-PSD; AM-PSD) were placed in the pelvic bone. Three implants per group were examined histologically and six implants were tested biomechanically. After 2 and 8 weeks the bone-to-implant contact (BIC) total values of SE implants (43.7±12.2; 53.3±9.0%) and SE-PSD (46.7±4.5; 61.7±4.9%) as well as AM implants (20.49±5.1; 43.9±9.7%) and AM-PSD implants (19.7±3.5; 48.3±15.6%) showed no statistically significant differences. For SE-PSD and AM-PSD a separate analysis of only the cancellous BIC demonstrated a statistically significant difference after 2 and 8 weeks. Biomechanical findings proved the overall increased stability of the porous implants after 8 weeks. Overall, the great effect of implant macro design on osseointegration was further supported by additional phosphoserine-tethered dendrons for SE and AM implants.

Micro-CT analysis of the rodent jaw bone micro-architecture: A systematic review

Introduction

Knowledge about macro- and micro-structural characteristics may improve in vivo estimation of the quality and quantity of regenerated bone tissue. For this reason, micro-CT imaging has been applied to evaluate alveolar bone remodelling, alterations of periodontal ligament thickness and cortical and trabecular bone changes in rodent jaw bones. In this paper, we provide a systematic review on the available micro-CT literature on jaw bone micro-architecture.

Methodology

A detailed search through the PubMed database was performed. Articles published up to December 2013 and related to maxilla, mandible and condyle with quantitatively analysed bone micro-architectural parameters were considered eligible for inclusion. Two reviewers assessed the search results according to inclusion criteria designed to identify animal studies quantifying the bone micro-architecture of the jaw rodent bones in physiological or drug-induced disease status, or in response to interventions such as mechanical loading, hormonal treatment and other metabolic alterations. Finally, the reporting quality of the included publications was evaluated using the tailored ARRIVE guidelines outlined by Vignoletti and Abrahamsson (2012).

Results

Database search, additional manual searching and assessment of the inclusion and exclusion criteria retrieved 127 potentially relevant articles. Eventually, 14 maxilla, 20 mandible and 12 condyle articles with focus on bone healing were retained, and were analysed together with 3 methodological papers. Each study was described systematically in terms of subject, experimental intervention, follow-up period, selected region of interest used in the micro-CT analysis, parameters quantified, micro-CT scanner device and software. The evidence level evaluated by the ARRIVE guidelines showed high mean scores (between 18 and 25; range: 0–25), indicating that most of the selected studies are well-reported. The major obstacles identified were related to sample size calculation, absence of adverse event descriptions, randomization or blinding procedures.

Conclusions

The evaluated studies are highly heterogeneous in terms of research topic and the different regions of interest. These results illustrate the need for a standardized methodology in micro-CT analysis. While the analysed studies do well according to the ARRIVE guidelines, the micro-CT procedure is often insufficiently described. Therefore we recommend to extend the ARRIVE guidelines for micro-CT studies.

•

This review investigates discrepancies between reports using micro-CT imaging of rodent jaw bone, the applied methodology and reported results.

•

Knowledge about the bone micro-architecture of the rodent jaw is scarce.

•

Jaw bone micro-architecture varies according to ROI selections and the methodology applied to define a specific region are insufficient.

Ag-plasma modification enhances bone apposition around titanium dental implants: an animal study in Labrador dogs

Dental implants with proper antibacterial ability as well as ideal osseointegration are being actively pursued. The antimicrobial ability of titanium implants can be significantly enhanced via modification with silver nanoparticles (Ag NPs). However, the high mobility of Ag NPs results in their potential cytotoxicity. The silver plasma immersion ion-implantation (Ag-PIII) technique may remedy the defect. Accordingly, Ag-PIII technique was employed in this study in an attempt to reduce the mobility of Ag NPs and enhance osseointegration of sandblasted and acid-etched (SLA) dental implants. Briefly, 48 dental implants, divided equally into one control and three test groups (further treated by Ag-PIII technique with three different implantation parameters), were inserted in the mandibles of six Labrador dogs. Scanning electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectrometry were used to investigate the surface topography, chemical states, and silver release of SLA- and Ag-PIII-treated titanium dental implants. The implant stability quotient examination, Microcomputed tomography evaluation, histological observations, and histomorphometric analysis were performed to assess the osseointegration effect in vivo. The results demonstrated that normal soft tissue healing around dental implants was observed in all the groups, whereas the implant stability quotient values in Ag-PIII groups were higher than that in the SLA group. In addition, all the Ag-PIII groups, compared to the SLA-group, exhibited enhanced new bone formation, bone mineral density, and trabecular pattern. With regard to osteogenic indicators, the implants treated with Ag-PIII for 30 minutes and 60 minutes, with the diameter of the Ag NPs ranging from 5–25 nm, were better than those treated with Ag-PIII for 90 minutes, with the Ag NPs diameter out of that range. These results suggest that Ag-PIII technique can reduce the mobility of Ag NPs and enhance the osseointegration of SLA surfaces and have the potential for future use.

In-vivo bone response to titanium screw implants anodized in sodium sulfate

PURPOSE

To evaluate the early bone response to a nanotextured dental implant treated with sodium sulfate (Na2SO4), using a rabbit model.

METHODS

Twelve animals were randomly divided into group 1 (Control) - machined implants and group 2 (Test) - nanotextured implants. Extra-oral incision was performed to provide access to intended surgical site where the dental implant was inserted immediately after the extraction of the mandibular first premolar. Implant surface characterization was performed by scanning electron microscopy attached to energy dispersive spectroscopy and interferometry. Three weeks after surgery, the animals were induced to death and undecalcified sections of the samples were prepared for histological and histomorphometrical analysis.

RESULTS

Surface characterization of the implant demonstrated enhanced surface area of anodized group compared to Control group with 19.2% ± 6.2 versus 1.6 ± 0.7, respectively. Histological evaluation demonstrated new bone formation starting from the buccal and lingual cortical walls on both groups. After three weeks, significant higher bone contact of 27% (p<0.05) was observed to nanotextured compared to machined implants (Control group).

CONCLUSION

The anodization with sodium sulfate nanostructures to the implant surface that resulted in faster osseointegration.