A Micro-computed Tomography Analysis of Marginal and Internal Fit of Endocrowns Fabricated from Three CAD/CAM Materials.

OBJECTIVE: To assess the marginal and internal misfit of endocrowns fabricated from a resin matrix ceramic (CS), a partially crystallized (EMC), and a fully crystallized (ILS) lithium disilicate glass-ceramic. METHODS AND MATERIALS: Thirty human premolar teeth restored with endocrowns were investigated. Three CAD/CAM materials were used (n=10 per group): CS, EMC, and ILS. Two-dimensional (2D) analysis of marginal and internal misfit was performed on micro-computed tomography scans before and after adhesive bonding. Further, three-dimensional (3D) analysis was performed to determine the total internal volume discrepancy. Surface roughness of the fitting surfaces of endocrowns was characterized using optical profilometry and scanning electron microscopy. RESULTS: Adhesive bonding did not significantly affect marginal or internal misfit (p≥0.093). Differences in marginal misfit among the experimental groups were not statistically significant (p≥0.221). However, differences in 2D internal misfit were statistically significant; the CS group exhibited the largest internal misfit (p=0.001), while no significant difference was found between other groups (p=0.123). The largest discrepancies were observed at the pulpal floor and cervical region of all investigated specimens. No statistically significant difference was found in 3D misfit between ILS and EMC groups (p=0.711); however both exhibited statistically lower 3D misfit values compared to the CS group (p≤0.037). ILS endocrowns exhibited the smoothest and most homogenous fitting surface profile (p<0.001). However, there was no significant correlation between 2D internal misfit and the surface roughness (p≥0.082). CONCLUSIONS: The choice of CAD/CAM material may influence the fitting accuracy of endocrowns. The investigated lithium disilicate glass-ceramics conferred superior internal fit for endocrowns compared to resin matrix ceramic.

Increased Handpiece Speeds without Air Coolant: Aerosols and Thermal Impact.

This study assessed the impact of increased speed of high-speed contra-angle handpieces (HSCAHs) on the aerosolization of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surrogate virus and any concomitant thermal impact on dental pulp. A bacteriophage phantom-head model was used for bioaerosol detection. Crown preparations were performed with an NSK Z95L Contra-Angle 1:5 (HSCAH-A) and a Bien Air Contra-Angle 1:5 Nova Micro Series (HSCAH-B) at speeds of 60,000, 100,000, and 200,000 revolutions per minute (rpm), with no air coolant. Bioaerosol dispersal was measured with Φ6-bacteriophage settle plates, air sampling, and particle counters. Heating of the internal walls of the pulp chambers during crown preparation was assessed with an infrared camera with HSCAH-A and HSCAH-B at 200,000 rpm (water flows ≈15 mL min-1 and ≈30 mL min-1) and an air-turbine control (≈23.5 mL min-1) and correlated with remaining tissue thickness measurements. Minimal bacteriophage was detected on settle or air samples with no notable differences observed between handpieces or speeds (P > 0.05). At all speeds, maximum settled aerosol and average air detection was 1.00 plaque-forming units (pfu) and 0.08 pfu/m3, respectively. Irrespective of water flow rate or handpiece, both maximum temperature (41.5°C) and temperature difference (5.5°C) thresholds for pulpal health were exceeded more frequently with reduced tissue thickness. Moderate and strong negative correlations were observed based on Pearson's correlation coefficient, between remaining dentine thickness and either differential (r = -0.588) or maximum temperature (r = -0.629) measurements, respectively. Overall, HSCAH-B generated more thermal energy and exceeded more temperature thresholds compared to HSCAH-A. HSCAHs without air coolant operating at speeds of 200,000 rpm did not increase bioaerosolization in the dental surgery. Thermal risk is variable, dependent on handpiece design and remaining dentine thickness.

Dental Mitigation Strategies to Reduce Aerosolization of SARS-CoV-2.

Limiting infection transmission is central to the safety of all in dentistry, particularly during the current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Aerosol-generating procedures (AGPs) are crucial to the practice of dentistry; it is imperative to understand the inherent risks of viral dispersion associated with AGPs and the efficacy of available mitigation strategies. In a dental surgery setting, crown preparation and root canal access procedures were performed with an air turbine or high-speed contra-angle handpiece (HSCAH), with mitigation via rubber dam or high-volume aspiration and a no-mitigation control. A phantom head was used with a 1.5-mL min-1 flow of artificial saliva infected with Φ6-bacteriophage (a surrogate virus for SARS-CoV-2) at ~108 plaque-forming units mL-1, reflecting the upper limits of reported salivary SARS-CoV-2 levels. Bioaerosol dispersal was measured using agar settle plates lawned with the Φ6-bacteriophage host, Pseudomonas syringae. Viral air concentrations were assessed using MicroBio MB2 air sampling and particle quantities using Kanomax 3889 GEOα counters. Compared to an air turbine, the HSCAH reduced settled bioaerosols by 99.72%, 100.00%, and 100.00% for no mitigation, aspiration, and rubber dam, respectively. Bacteriophage concentrations in the air were reduced by 99.98%, 100.00%, and 100.00% with the same mitigations. Use of the HSCAH with high-volume aspiration resulted in no detectable bacteriophage, both on nonsplatter settle plates and in air samples taken 6 to 10 min postprocedure. To our knowledge, this study is the first to report the aerosolization in a dental clinic of active virus as a marker for risk determination. While this model represents a worst-case scenario for possible SARS-CoV-2 dispersal, these data showed that the use of HSCAHs can vastly reduce the risk of viral aerosolization and therefore remove the need for clinic fallow time. Furthermore, our findings indicate that the use of particle analysis alone cannot provide sufficient insight to understand bioaerosol infection risk.

The Effects of Colored Pigments on the Translucency of Experimental Dental Resin Composites.

OBJECTIVE: Colored pigments are incorporated into dental resin composites to produce clinically acceptable shades for restorative materials but studies on their effects on translucency are rare. The aim of this study was to examine the effects of the addition of different colored pigments on the translucency of experimental dental resin composites. MATERIALS AND METHODS: 12 types of experimental dental resin composites containing different concentrations of red and yellow iron oxide pigments were formulated and light-cured. Total and diffuse translucency as well as CIE L*a*b* values were measured and the color differences were calculated. RESULTS: There was a statistically significant difference in the translucency values between the composites with no pigments and the composites with increasing concentrations of the pigments (p<0.05). The translucency decreased as the concentration of the pigments increased. However at pigment concentrations greater than 0.02%, the translucency of the composites reached a plateau and ceased to be influenced by the addition of the pigments (p⟨0.05). All color differences were in the range of 3.62-16.00 ΔE*ab unit. CONCLUSIONS: The pigments used in this study can influence the translucency of the experimental resin composites and should be considered as an important factor by clinicians to achieve optimal esthetic restorative outcome.

Wound Discharge After Pharmacological Thromboprophylaxis in Lower Limb Arthroplasty.

BACKGROUND: The benefits vs risk of pharmacological prophylaxis for thromboembolic disease in orthopedic patients remain controversial. Pharmacological thromboprophylaxis regimes are commonly used in this patient group. Few studies specifically examine wound complications attributable to this therapy. In this prospective trial, we investigated the effect of various regimens on postoperative wounds. METHODS: A prospective, observational, multicenter study involving patients undergoing elective hip or knee arthroplasty was undertaken. Patients were divided into 3 groups depending on thromboprophylaxis: no anticoagulation, aspirin, or low molecular weight heparin (LMWH) (enoxaparin). Surgical wounds were evaluated for each regime using the Southampton Wound Assessment Score. RESULTS: Over a 12-month period, 327 patients were enrolled with a mean age of 68.1 years (±11.2 years). There were 105 patients in the no anticoagulation group (32.1%), 97 patients in the aspirin group (29.7%), and 125 patients in the LMWH group (38.2%). Wound scores were evaluated for evidence and amount of discharge. The use of LMWH conferred a 4.92 times greater risk and aspirin a 3.64 times greater risk of wound discharge than no pharmacological thromboprophylaxis (P < .0001). There were no significant differences in the incidence of deep vein thrombosis or pulmonary embolus between groups either as an inpatient or postdischarge. CONCLUSION: There is a significant increase in the risk of wound discharge when aspirin or LMWH is used in arthroplasty patients. As potential complications of wound problems are significant, a more balanced view of risk vs benefit needs to be taken when prescribing thromboprophylaxis for this patient group.

The introduction of digital dental technology into BDS curricula.

The aim of this study was to determine the degree to which digital dental technologies have been introduced into the curricula of UK dental schools. A survey was carried out of all the UK dental schools that teach undergraduate dental students. The survey contained six questions and was designed to determine if digital dental technology techniques or systems were being taught in the curricula, what these techniques were, and whether the school dental laboratories supported these techniques. Sixteen schools were surveyed and 11 replied: a response rate of 69%. Forty-five percent of the schools that replied did not teach digital dental technology in their curriculum. Of the 55% of schools who did teach digital dental technology, 50% gave lectures or demonstrations while the other 50% allowed practical involvement by the student. Two thirds of these stated that not all the students participated in practical usage. Seventy-three percent of the schools that replied had dental laboratories using some, but not all the digital dental technology techniques listed. Eighty percent of the schools that were not teaching digital dental technology said it was because it was not included in the curriculum, and 20% stated it was due to a lack of technical expertise or support.

Knee joint preservation with combined neutralising high tibial osteotomy (HTO) and Matrix-induced Autologous Chondrocyte Implantation (MACI) in younger patients with medial knee osteoarthritis: a case series with prospective clinical and MRI follow-up over 5 years.

PURPOSE: There is no ideal treatment for younger patients with medial knee osteoarthritis (OA) and varus malalignment. We have investigated the first case series of combined neutralising high tibial osteotomy (HTO) and Matrix-induced Autologous Chondrocyte Implantation (MACI) with MRI. Treatment goals were clinical improvement and delay of arthroplasty. METHODS: Between 2002 and 2005 18 patients (Mean age 47 years) underwent surgery. Exclusion criteria were lateral compartment and advanced patellofemoral OA. The Knee Injury and Osteoarthritis Outcome Score (KOOS), six minute walk test (6MWT) and a validated MRI score were outcome measures. RESULTS: There were significant improvements (p<0.05) in all five KOOS domains. Four were significantly maintained to 5 years. The domain "symptoms" and results in the 6MWT dropped off at 5 years. MRI results were first significantly improved (24/12) but declined at 60 months. Good quality infill was found in 33% patients at the study endpoint (n=5/15). Histological investigation of one knee demonstrated full-thickness hyaline-like cartilage (20/12). After 2 early failures and one graft detachment graft fixation was changed (Smart nails instead of sutures in 14 cases). Graft hypertrophy requiring a chondroplasty occurred once. There were no other major complications. Specific minor complications included patellar tendinitis (n=8). CONCLUSIONS: This combined procedure provides a safe treatment option for younger patients with medial knee OA and varus alignment with significant clinical improvement at 5 years. However, overall graft survival and cartilage infill were poor. Larger studies are needed to statistically verify predictors for longer term cartilage repair in these patients.

Nanoparticles for dentine tubule infiltration: an in vitro study.

Nanosized particles of hydroxyapatite were produced by a hydrothermal synthesis technique. Reaction time and starting pH were varied in order to produce a range of particle dimensions and morphologies. The particles were suspended in alcohol and used for in-vitro trials of dentinal tubule infiltration in etched sections of clinically extracted human molars. Particles were of rod-like morphology, and decreased in aspect ratio as the starting pH was raised. Particles prepared at pH 12 had a mean length of approximately 70 nm and diameter of approximately 30 nm. These showed the most promising infiltration results, with up to 90% of the tubules being fully or partially occluded. Comparisons were made with commercially-available 40 nm spherical silica particles. Information on the depth of infiltration was obtained from sections of dentine prepared using focussed ion beam milling (FIB-SEM).

Malignant fibrous histiocytoma complicating nephrogenic systemic fibrosis post liver transplantation.

A 46-year-old man with cirrhosis secondary to hepatitis C virus infection and alcohol underwent orthotopic liver transplantation, which required urgent re-grafting because of biliary sepsis from necrosis of the left liver lobe. Recovery was complicated by renal failure and nephrogenic systemic fibrosis (probably related to intravenous gadolinium exposure). He subsequently developed a malignant fibrous histiocytoma. We present this case highlighting the occurrence of two rare conditions in the same patient following liver transplantation. We believe this is the first case of its kind to be reported.

An evaluation of the effect of non-setting calcium hydroxide on human dentine: a pilot study.

AIM: To evaluate the effect of non-setting calcium hydroxide (NSCH) on the hardness and elastic modulus of dentine from extracted permanent premolar human teeth. METHODS: 30 freshly extracted single rooted human premolar teeth were decoronated and the roots then sectioned longitudinally into equal halves. In the experimental group a thin layer of NSCH was applied whilst the control group had no medicament. After 1, 3 and 6 months, nanoindentation was used to assess dentine hardness and the modulus of elasticity. Scanning Electron Microscopy (SEM) was used to visualize the depth of penetration of NSCH into the dentinal tubules. RESULTS: SEM images showed that there were no structural changes in the dentine slabs that had NSCH application after 1, 3 or even 6 months. However, penetration of NSCH into the dentine tubules was seen at both 3 and 6 months with a significant reduction in the hardness of dentine observed at 3 (p<0.02) and 6 months (p<0.01). The modulus of elasticity was significantly lower (p<0.01) at 6 months. CONCLUSION: It appears that there is a significant reduction in the hardness of dentine with increasing periods of calcium hydroxide application. Prolonged application of NSCH could have a detrimental effect on dentine, making the dentine more prone to fracture.

Stabilisation of chronic flail chest: a novel approach of surgical fixation and osteogenesis.

A patient with chronic flail chest, severe persistent pain and chest wall deformity was successfully managed with open reduction and internal fixation of the ribs and application of a novel osteogenic protein.

Indirect selective laser sintering of apatite-wollostonite glass-ceramic.

This paper develops an indirect selective laser sintering (SLS) processing route for apatite-wollastonite (A-W) glass-ceramic, and shows that the processing route, which can create porous three-dimensional products suitable for bone implants or scaffolds, does not affect the excellent mechanical and biological properties of the glass-ceramic. 'Green parts' with fine integrity and well-defined shape have been produced from glass particles of single-size range or mixed-size ranges with acrylic binder in various ratios by weight. A subsequent heat treatment process has been developed to optimize the crystallization process, and an infiltration process has been explored to enhance mechanical strength. Three-point bending test results show flexural strengths of up to 102 MPa, dependent on porosity, and simulated body fluid (SBF) tests show that the laser sintered porous A-W has comparable biological properties to that of conventionally produced A-W.

Traditional vs accelerated approaches to post-operative rehabilitation following matrix-induced autologous chondrocyte implantation (MACI): comparison of clinical, biomechanical and radiographic outcomes.

OBJECTIVE: To determine the effectiveness of 'accelerated' compared to 'traditional' post-operative load bearing rehabilitation protocols following matrix-induced autologous chondrocyte implantation (MACI). METHOD: A randomized controlled study design was used to investigate clinical, biomechanical and radiographic assessment at 3 months post-surgery in 62 patients following MACI to the medial or lateral femoral condyle. Both rehabilitation interventions sought to protect the implant for an initial period, then incrementally increase load bearing. Under the 'accelerated' protocol, patients reached full weight bearing at 8 weeks post-surgery, compared to 11 weeks for the 'traditional' group. RESULTS: Patients in the 'accelerated' group achieved greater 6 min walk distances and daily activity levels as measured by accelerometry (P<0.05) compared to the 'traditional' group. Furthermore, the 'accelerated' group reported significantly better improvement in knee pain at 12 weeks as indicated by the Knee Injury and Osteoarthritis Outcome Score (P<0.05), and regardless of the rehabilitation protocol employed, no patient suffered any adverse effect to the implant as assessed by magnetic resonance imaging at 3 months. Comparison of each rehabilitation group with an unaffected control group revealed a significant difference in peak knee adduction and flexion moments for the traditional group (P<0.05). However, there was no difference for accelerated patients (P>0.05), which may demonstrate a faster return to knee loading patterns typically observed in unaffected subjects. CONCLUSION: The 'accelerated' load bearing approach that reduced the length of time spent ambulating on crutches resulted in reduced knee pain, improved function, no graft complications and may speed up the recovery of normal gait function. Patient follow-up to at least 24 months would be required to observe longer-term graft outcomes.

Effect of flexion/extension splintage post total knee arthroplasty on blood loss and range of motion -- a randomised controlled trial.

Previous published research has shown promising results with flexion splinting post total knee arthroplasty. Before instituting this practice, we conducted a randomised controlled trial to confirm any benefits over splinting in extension. Five patients were recruited into the trial. 5 were excluded. The flexion group consisted of 49 patients who had their knee placed in 70 degrees of flexion over an inactive CPM machine for 24 h post operation. The extension group consisted of 46 patients who were splinted in full extension for the first 24 h post operation. We assessed post-operative day 1 drain volume, haemoglobin and haematocrit, blood transfusions, duration of inpatient stay, range of motion and complications within 6 weeks of surgery. There was no significant difference between the two groups among any of the outcomes measured. As such, we have been unable to demonstrate any benefit with splintage in flexion post total knee arthroplasty and have not adopted it as part of our post-operative management.

Evidence that human cartilage and chondrocytes do not express calcitonin receptor.

OBJECTIVE: Calcitonin (CT) has been recently shown to exhibit direct protective effects on articular cartilage against joint degenerative disease. It has been proposed that CT might act via the CT receptor (CTR) to activate the cyclic AMP (cAMP) pathway and protect type II collagen degradation. In this study, we investigated the existence of CTR in human articular cartilage and chondrocytes, and examined the potential pharmacological effects and transduction pathway of salmon CT (sCT) in human chondrocytes. METHODS: Five human articular cartilage samples were examined for the expression of the CTR by polymerase chain reaction (PCR), immunostaining and Western blot analysis. cAMP levels in human chondrocyte stimulated with sCT were assessed by ELISA. The effect of sCT on the gene expression profiles, including aggrecan, type II collagen, MMP-1, MMP-3 and MMP-13, of human chondrocytes was also examined by relative quantitative Real-time PCR. RESULTS: We failed to detect the CTR at both the transcriptional and protein levels in human chondrocytes and cartilage tissue by PCR, immunostaining and Western blotting. cAMP levels were significantly elevated in human chondrocytes by forskolin (100muM) to more than 10-fold (P<0.001), however, were not induced by sCT (10(-7)M, 10(-8)M, 10(-9)M). Real-time PCR analysis demonstrated that sCT slightly reduced the gene expression of MMPs, although this effect was not statistically significant. CONCLUSION: In contrary to previous reports, our data indicate that human cartilage and chondrocytes do not express CTR. Furthermore, sCT does not appear to have direct effects on human chondrocytes. We propose that the chondroprotective effect of CT observed in vivo may be indirect via its impact on subchondral bone resorptive activity of osteoclasts.

Total knee replacement with and without patellar resurfacing: a prospective, randomised trial using the profix total knee system.

We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006).

Inhibition of biofilms associated with dentures and toothbrushes by tetrasodium EDTA.

AIMS: We examined the efficacy of tetrasodium EDTA in eradicating biofilms derived from salivary inocula or pure cultures of Candida albicans on discs of polymethyl methacrylate (PMMA) denture base or on toothbrushes that had been used normally for 4-8 weeks. Its efficiency in virus neutralization was also determined. METHODS AND RESULTS: Overnight (16 h) treatment with 4% (w/v) tetrasodium EDTA solution reduced salivary and C. albicans biofilm viable counts by > or =99%. Biofilm removal was confirmed using confocal laser scanning microscopy. Presence/absence of sucrose during biofilm formation had no effect on killing efficacy. Prolonged treatment of PMMA with tetrasodium EDTA did not influence subsequent formation of C. albicans biofilms or affect surface roughness of the PMMA, but it reduced subsequent biofilm formation from a salivary inoculum. Infectivities of herpes simplex virus and polio virus suspensions were reduced by >99.99% by treatment for 1 and 2 h, respectively. CONCLUSIONS: Tetrasodium EDTA solution efficiently disinfected toothbrushes and PMMA discs, with the detachment of biofilms, and rapidly neutralized both nonenveloped and enveloped viruses. SIGNIFICANCE AND IMPACT OF THE STUDY: Dentures and toothbrushes become contaminated by bacterial biofilms and by viruses. There is a need for disinfection methods that are rapidly effective, cost-effective, nontoxic and easily implemented. These studies indicate that tetrasodium EDTA solution has disinfection applications in the oral care field.

The effect of 24h non-stop hydrogen peroxide concentration on bovine enamel and dentine mineral content and microhardness.

OBJECTIVES: Tooth bleaching agents may adversely affect tooth structure. The aim of this study was to investigate the effect of hydrogen peroxide concentration on mineral loss and microhardness of bovine teeth. METHODS: Twenty-six freshly extracted intact bovine incisor teeth were stored in distilled water. Five teeth were sectioned and four samples (2 mm x 2 mm x 1.5 mm) each of enamel and dentine were obtained from each tooth. The samples of enamel and dentine were divided into four groups and immersed in either 0%, 3%, 10% or 30% (w/v) hydrogen peroxide solutions for 24h at 37 degrees C. Samples from the solutions were taken for ion release analysis using inductively coupled plasma mass spectrometry. The remaining 21 teeth were mounted in epoxy resin and the upper surface of the specimens were ground and polished to expose the enamel and dentine for microhardness measurements. These specimens were randomly divided into three equal groups and Vickers microhardness values were recorded on the enamel and dentine surfaces of each group before and after bleaching. RESULTS: The differences in ion release concentration after treatment with 0% (control) and each of 3%, 10% and 30% hydrogen peroxide (w/v) were statistically significant (p<0.025). The release of calcium and phosphorous ions increased with increasing hydrogen peroxide concentrations. A significant reduction (p<0.05) in Vickers microhardness values for enamel was recorded after bleaching. CONCLUSIONS: Ion release from both enamel and dentine increased with increasing hydrogen peroxide concentration. Microhardness of enamel decreased significantly with bleaching.

MRI and clinical evaluation of collagen-covered autologous chondrocyte implantation (CACI) at two years.

We present our experience with the collagen-covered autologous chondrocyte implantation (CACI) technique. Thirty two implantations were performed in 31 patients. Clinical outcome was measured using the KOOS score and the 6-minute walk test, as well as an MRI scoring protocol (75% of patients had a complete data set for MRI follow-up) to describe the repair tissue generated by CACI. We have also correlated our MRI results with our clinical outcome. To the authors knowledge there are no comparative studies of MRI and clinical outcome following CACI in the current literature. Patients demonstrated an increased walk distance that improved significantly from 3 months to 24 months postoperatively (p<0.05). Analysis of the KOOS results demonstrated a significant (p<0.05) improvement in four of the five subscales from 3 months to 24 months after CACI, with the most substantial gains made in the first 12 months. Patients demonstrated an increased MRI outcome score over time that improved significantly from 3 months to 24 months postoperatively (p<0.05). We observed an 8% incidence of hypertrophic growth following CACI. We report one partial graft failure, defined by clinical, MRI and histological evaluation, at the one year time point. In contrast to the current literature we report no incidence of manipulation under anesthesia (MUA) following CACI. This research demonstrates that autologous chondrocytes implanted under a type I/III collagen patch regenerates a functional infill material, and as a result of this procedure, patients experienced improved knee function and MRI scores. Whilst our results indicated a statistically significant relationship between the MRI and functional outcome following CACI, MRI cannot be used as surrogate measure of functional outcome following CACI, since the degree of association was only low to moderate. That is, functional outcome following CACI cannot be predicted by the morphological MRI assessment of the repair tissue at the post-surgery time points to 24 months.