Methods of assessing periodontal regeneration

Harnessing the Native Extracellular Matrix for Periodontal Regeneration Using a Melt Electrowritten Biphasic Scaffold

Scaffolds have been used to promote periodontal regeneration by providing control over the spacio-temporal healing of the periodontium (cementum, periodontal ligament (PDL) and alveolar bone). This study proposes to enhance the biofunctionality of a biphasic scaffold for periodontal regeneration by means of cell-laid extracellular matrix (ECM) decoration. To this end, a melt electrowritten scaffold was cultured with human osteoblasts for the deposition of bone-specific ECM. In parallel, periodontal ligament cells were used to form a cell sheet, which was later combined with the bone ECM scaffold to form a biphasic PDL-bone construct. The resulting biphasic construct was decellularised to remove all cellular components while preserving the deposited matrix. Decellularisation efficacy was confirmed in vitro, before the regenerative performance of freshly decellularised constructs was compared to that of 3-months stored freeze-dried scaffolds in a rodent periodontal defect model. Four weeks post-surgery, microCT revealed similar bone formation in all groups. Histology showed higher amounts of newly formed cementum and periodontal attachment in the fresh and freeze-dried ECM functionalised scaffolds, although it did not reach statistical significance. This study demonstrated that the positive effect of ECM decoration was preserved after freeze-drying and storing the construct for 3 months, which has important implications for clinical translation.

Clinical and Radiographic Evaluation of Combined Acemannan and Periodontal Surgery Induced-Periodontal Regeneration: 5-Year Follow-up Case Report

Background and Objective:

Acemannan, a polysaccharide extracted from aloe vera gel, accelerates oral wound healing, reparative dentin formation, and bone formation in extraction sockets. In this report, we evaluated the efficacy of combined acemannan and periodontal surgery on periodontal regeneration in severe periodontitis cases requiring periodontal surgery.

Case Presentation and Discussion:

Three chronic periodontitis patients with probing pocket depths of at least 6 mm and two- or three-walled vertical bone defects after initial periodontal therapy were included. The patients underwent minimally invasive periodontal surgery with acemannan sponges placed in the defect. Maintenance recall was scheduled every 6 months for 5 years. Clinical and radiographic evaluations were performed to assess the effects of the combined acemannan and periodontal surgery on periodontal regeneration. The patients demonstrated improved clinical parameters and increased radiographic bone fill at the 5-year follow-ups. The percentage bone fill in the three-walled defect, combined two- and three-walled defect, and two-walled defect cases were 70%, 60%, and 20%, respectively. The underlying mechanism of action of acemannan in periodontal regeneration was also discussed.

Conclusion:

Acemannan sponges can be used as an adjunct to periodontal surgery for periodontal regeneration.

Immuno-histopathologic evaluation of mineralized plasmatic matrix in the management of horizontal ridge defects in a canine model (a split-mouth comparative study)

Our research aimed to investigate the effect of combining biphasic calcium phosphate (BCP) alloplast with mineralized plasmatic matrix (MPM) as compared with platelet-rich fibrin (PRF) on the quality and quantity of bone formation and maturation at surgically created horizontal critical-sized ridge defects (HRDs) in a canine model. We used a split-mouth design using the third and fourth mandibular premolars of the mongrel dogs. Twelve defects on the left side (experimental group, I) were managed with MPM composite mixed with BCP alloplast, MPM compact layer. On the right side (control group, II), another 12 defects were managed with PRF mixed with BCP alloplast, followed by the application of PRF compact strips. Finally, both were covered by a collagen membrane. Dogs were euthanized at 4, 8, and 12 weeks, and the studied defects were processed to evaluate treatment outcome, including mean percentage of bone surface area, collagen percentage, and osteopontin (OPN) immunoreaction. Our results revealed that the mean percentage of bone surface area was significantly increased in the experimental group treated with MPM at all time intervals as compared with the PRF group. Decreased collagen percentage and increased OPN immunoreactivity showed significant results in the MPM group as compared with PRF at 4 and 8 weeks postoperatively, respectively. In conclusion, MPM accelerates the formation of superior new bone quality when used in the treatment of HRDs.

Assessment of alveolar bone changes in response to minimally invasive periodontal surgery: A cone-beam computed tomographic evaluation

Purpose

The aim of this study was to evaluate 3-dimensional cone-beam computed tomography (CBCT) images of alveolar bone changes in patients who underwent minimally invasive periodontal surgery-namely, the pinhole surgical technique (PST).

Materials and Methods

Alveolar bone height was measured and compared on CBCT images of 254 teeth from 23 consecutive patients with Miller class I, II, or III recession who had undergone PST. No patient with active periodontal disease was selected for surgery. Two different methods were used to assess the alveolar bone changes postoperatively. In both methods, the distance between the apex of the tooth and the mid-buccal alveolar crestal bone on pre- and post-surgical CBCT studies was measured.

Results

An average alveolar bone gain >0.5 mm following PST was identified using CBCT (P=0.05). None of the demographic variables, including sex, age, and time since surgery, had any significant effect on bone gain during follow-up, which ranged from 8 months to 3 years.

Conclusion

PST appears to be a promising treatment modality for recession that results in stable clinical outcomes and may lead to some level of resolution on the bone level. More long-term studies must be done to evaluate the impact of this novel technique on bone remodeling and to assess sustained bone levels within a larger study population.

Clinical, radiographic, and patient-centered outcomes after use of enamel matrix proteins for the treatment of intrabony defects in patients with aggressive periodontitis: A 12-month multicenter clinical trial

BACKGROUND

The aim of this study was to evaluate the clinical, radiographic and patient-centered results of enamel matrix derivative (EMD) therapy in intrabony defects in aggressive periodontitis (AgP) patients and compare them with those in chronic periodontitis (CP) patients.

METHODS

Sixty intrabony defects in AgP and CP patients associated with ≥ 6 mm residual probing pocket depth (PPD) were included and randomly assigned to one of three groups: AgP+CS (conservative surgery) (n = 20); AgP+CS/EMD (n = 20); CP+CS/EMD (n  =  20). Clinical parameters were measured at baseline and after 6 and 12 months. Defect resolution (DR) and bone filling (BF) were used for radiographic analysis. The quality of life was recorded at baseline and 6 months using OHIP-14 and VAS scale in the early post-therapy period.

RESULTS

PPD and relative clinical attachment level (rCAL) improved for all groups during follow-up (P ≤ 0.05), and AgP+CS/EMD presented a higher rCAL gain (2.4 ± 1.0 mm) when compared to AgP control patients (1.6 ± 1.6 mm, P ≤ 0.05) after 12 months. No difference was observed between AgP+CS/EMD and CP+CS/EMD groups (P > 0.05). No radiographic differences were observed among groups at any time point (P > 0.05). All the groups reported a positive impact on OHIP-14 total score, without differences among them.

CONCLUSIONS

EMD therapy of intrabony defects promotes additional benefits in AgP patients, presenting a similar regeneration rate compared to CP patients, and has proven to be a viable therapy for the treatment of individuals with AgP.

Experimental and clinical studies on regenerative periodontal therapy

The recognition of a periodontal therapy as a regenerative procedure requires the demonstration of new cementum, periodontal ligament, and bone coronal to the base of the defect. A diversity of regenerative strategies has been evaluated, including root surface conditioning, bone grafts and bone substitute materials, guided tissue regeneration, enamel matrix proteins, growth/differentiation factors, combined therapies and, more recently, tissue-engineering approaches. The aim of this chapter of Periodontology 2000 is to review the research carried out in Latin America in the field of periodontal regeneration, focusing mainly on studies using preclinical models (animal models) and randomized controlled clinical trials. This review may help clinicians and researchers to evaluate the current status of the therapies available and to discuss the challenges that must be faced in order to achieve predictable periodontal regeneration in clinical practice.

Histopathological and biochemical evaluation of paeoniflorin administration in an experimental periodontitis model

The purpose of this study was to evaluate the effects of administered Paeoniflorin (Pae) on periodontal tissues within an experimental periodontitis model. Forty male Wistar rats were used in this study and experimental periodontitis was created in all rats except in the control group (n = 10, first group). In the periodontitis group, experimental periodontitis was created but no other application was performed (n = 10, second group). In the other groups created experimental periodontitis, systemic Pae (n = 10, third group) or saline (n = 10, fourth group) was applied. A biochemical analysis of the gingival vascular endothelial growth factor (VEGF) levels and a histomorphometric analysis (measurements of the area of alveolar bone, alveolar bone resorption, and attachment loss) were performed. In the Pae group, the area of the alveolar bone was increased, while alveolar bone resorption and attachment loss decreased. Gingival VEGF levels increased in all groups that created experimental periodontitis and the greatest increase seen in the Pae group. Histomorphometric and biochemical analyses in this study suggest that Pae has a curative effect on periodontal tissues. However, additional studies are needed to confirm these results.

Histopathological and biochemical evaluation of the effect of Paeoniflorin on the periodontium during and after periodontitis formation in rats

OBJECTIVES

Appraise the effect of systemic Paeoniflorin (Pae) application on the periodontium during and after induction of experimental periodontitis in the presence of ligature and after its removal.

DESIGN

Seventy male Wistar rats were separated into seven equal groups. The first group was reserved as healthy control group (Group 1: no periodontitis, no medication) and experimental periodontitis was induced with ligature in the remaining rats. In experimental periodontitis groups, Pae or saline was administered systemically in three differet periods; during the experimental periodontitis induction (period 1), after experimental periodontitis induction which ligature removed (period 2) or ligature kept in position (period 3). Only, one of the groups acted as the control periodontitis group and received no treatment. Experimental periodontitis groups were as follows; Group 2: medication in period 1, Group 3: periodontitis and no medication, Group 4: medication in period 2, Group 5: saline application in period 2, Group 6: medication in period 3, Group 7: saline application in period 3. Matrix metalloproteinases-9 (MMP-9) levels and interleukin-10 (IL-10) levels were detected biochemically and histomorphometric analyses were performed. These analyses included measurements of the area of alveolar bone, the level of alveolar bone, and attachment loss.

RESULTS

Area of alveolar bone and IL-10 levels were higher in the Pae-administered groups; level of alveolar bone, attachment loss, and MMP-9 levels were correspondingly lower (P < 0.05). The beneficial effects at histomorphometrical and biochemical levels of Pae were the strongest in the rats that were administered Pae after the removal of ligature.

CONCLUSIONS

Systemically administered Pae had a positive effect on the healing of periodontal tissues. Pae can be used as a new therapeutic agent for periodontal diseases, but microbiology-based studies and more extensive biochemistry-based experimental and clinical studies are needed to address this possibility.

Recent Advances of Useful Cell Sources in the Periodontal Regeneration

Background:

Periodontitis is an inflammatory disease that can result in destruction of the tooth attachment apparatus. Therefore, periodontal tissue regeneration is currently an important focus of research in the field. Approaches using stem cells and reprogrammed cells, such as induced pluripotent stem cells (iPSCs) or trans-differentiated cells, represent the cutting edge in periodontal regeneration, and have led to many trials for their clinical application.

Objectives and Results:

In this review, we consider all available stem cell sources, methods to obtain the cells, their capability to differentiate into the desired cells, and the extent of their utilization in periodontal regeneration. In addition, we introduce the new concepts of using iPSCs and transdifferentiated cells for periodontal regeneration. Finally, we discuss the promise of tissue engineering for improving cell therapy outcomes for periodontal regeneration.

Conclusions:

Despite their limitations, iPSCs and trans-differentiated cells may be promising cell sources for periodontal tissue regeneration. Further collaborative investigation is required for the effective and safe application of these cells in combination with tissue engineering elements, like scaffolds and biosignals.

The efficacy of transgingival probing in class II buccal furcation defects treated by guided tissue regeneration

Background:

The objectives of the present study were to establish transgingival probing as an evaluating method in the clinical studies of periodontal regenerative techniques and to compare the effectiveness of transgingival probing to the surgical entry.

Materials and Methods:

Ten systemically healthy persons (20–50 years) with moderate to severe chronic periodontitis participated in this study. These cases were recruited into the study only when they fulfilled the eligibility criteria. Vertical probing depth (VPD) and horizontal probing depth (HPD) of furcation defects were measured with and without opening the flap, following local anesthesia during initial surgery and at 6 months after collagen membrane placement. The defect fill (DF) was also noted. The mean measurements of clinical parameters were compared by two-tailed paired t-test at 5% level of significance.

Results:

The difference between the measurements of VPD and HPD taken during transgingival probing and after opening the flap was lie in the range of 0.10–0.30 mm at the time of initial surgery and 6 months after surgery that was not statistically significant. Persons experienced slight discomfort or pain during opening the flap as compared to transgingival probing, and this method was also appreciated by the patients as it is easy, simple and does not involve the surgical procedure.

Conclusion:

The results of the study suggest that measurements recorded during transgingival probing and after opening the flap do not influence the required outcome of regenerative therapies, i.e., DF that was not statistically significant difference from surgical reentry. Therefore, it was concluded that transgingival probing could be used as evaluating parameters to see the outcome of regenerative surgeries and the surgical reentry procedure may be avoided because it is a second surgical procedure, time-consuming and interrupts the healing process.

Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

Surgical Treatment of Periodontal Intrabony Defects with Calcium Sulphate in Combination with Beta-Tricalcium Phosphate: Clinical Observations Two Years Post-Surgery

The study was designed to evaluate the clinical outcome of a composite material, beta-tricalcium phosphate in combination with calcium sulphate, in the treatment of periodontal intrabony defects. The combination of these materials is believed to aid in guided tissue regeneration owing to their properties. A total of 47 teeth with intrabony defects in 26 periodontitis patients were treated with Fortoss® Vital (Biocomposites, Staffordshire, UK). Clinical parameters were evaluated which included changes in probing depth, clinical attachment level/loss and gingival recession at the baseline and 2 years postoperatively. The mean differences in measurements between the baseline and 2 years postoperatively were a reduction of 2.07±1.14 mm (p=0.000) in case of probing depth and a gain of 1.93±1.36 mm (p=0.000) in clinical attachment level; but an increase of 0.14±0.73 mm (p=0.571) in gingival recession. The study results show that the treatment with a combination of beta tricalcium phosphate and calcium sulphate led to a significantly favorable clinical improvement in periodontal intrabony defects 2 years after the surgery.

Assessment of MMP-1, MMP-8 and TIMP-2 in experimental periodontitis treated with kaempferol

Purpose

The objective of this study was to investigate the effect of a dietary flavonoid, kaempferol, which has been shown to possess antiallergic, anti-inflammatory, anticarcinogenic, and antioxidant activities on the periodontium by histomorphometric analysis and on gingival tissue matrix metalloproteinase-1 (MMP-1), MMP-8, and tissue inhibitor of metalloproteinase-2 (TIMP-2) by biochemical analysis of rats after experimental periodontitis induction.

Methods

Sixty Wistar rats were randomly divided into six groups of ten rats each, and silk ligatures were placed around the cervical area of the mandibular first molars for 15 days, except in the healthy control rats. In the experimental periodontitis groups, systemic kaempferol (10 mg/kg/2d) and saline were administered by oral gavage at two different periods (with and without the presence of dental biofilm) to all rats except for the ten non-medicated rats. Alveolar bone area, alveolar bone level, and attachment level were determined by histomorphometric analysis, and gingival tissue levels of MMP-1, MMP-8, and TIMP-2 were detected by biochemical analysis.

Results

Significantly greater bone area and significantly less alveolar bone and attachment loss were observed in the kaempferol application groups compared to the control groups (P<0.05). In addition, gingival tissue MMP-1 and -8 levels were significantly lower in the kaempferol application groups compared to the control groups and the periodontitis group (P<0.001). There were no statistically significant differences in TIMP-2 levels between the kaempferol and saline application groups (P>0.05).

Conclusions

Kaempferol application may be useful in decreasing alveolar bone resorption, attachment loss, and MMP-1 and -8 production in experimental periodontitis.

Nutrient supplementation may adversely affect maternal oral health--a randomised controlled trial in rural Malawi

Nutritional supplementation during pregnancy is increasingly recommended especially in low-resource settings, but its oral health impacts have not been studied. Our aim was to examine whether supplementation with multiple micronutrients (MMN) or small-quantity lipid-based nutrient supplements affects dental caries development or periodontal health in a rural Malawian population. The study was embedded in a controlled iLiNS-DYAD trial that enrolled 1391 pregnant women <20 gestation weeks. Women were provided with one daily iron-folic acid capsule (IFA), one capsule with 18 micronutrients (MMN) or one sachet of lipid-based nutrient supplements (LNS) containing protein, carbohydrates, essential fatty acids and 21 micronutrients. Oral examination of 1024 participants was conducted and panoramic X-ray taken within 6 weeks after delivery. The supplement groups were similar at baseline in average socio-economic, nutritional and health status. At the end of the intervention, the prevalence of caries was 56.7%, 69.1% and 63.3% (P = 0.004), and periodontitis 34.9%, 29.8% and 31.2% (P = 0.338) in the IFA, MMN and LNS groups, respectively. Compared with the IFA group, women in the MMN group had 0.60 (0.18-1.02) and in the LNS group 0.59 (0.17-1.01) higher mean number of caries lesions. In the absence of baseline oral health data, firm conclusions on causality cannot be drawn. However, although not confirmatory, the findings are consistent with a possibility that provision of MMN or LNS may have increased the caries incidence in this target population. Because of the potential public health impacts, further research on the association between gestational nutrient interventions and oral health in low-income settings is needed.

Two-year randomized clinical trial of enamel matrix derivative treated infrabony defects: radiographic analysis

BACKGROUND

This split-mouth, double-blind randomized controlled trial evaluated radiographic changes in infrabony defects treated with open flap debridement (OFD) or OFD associated with enamel matrix derivative (EMD) after a 24-month follow-up. The radiographic distance from the CEJ to the bottom of the defect (BD) was considered the primary outcome. CEJ-BC and defect angle were secondary outcomes.

METHODS

Ten patients presenting 2 or more defects were selected. An individualized film holder was used to take standardized radiographs of the 43 defects, at baseline and after 24 months. Images were digitized and used to measure the distances from the cemento-enamel junction (CEJ) to the alveolar crest (AC), CEJ to the bottom of the defect (BD) and infrabony defect angle. Statistical analysis was performed in SPSS for Windows (version 5.2). Paired samples t test was used to compare test and control groups and to evaluate changes within each group. The level of significance was set at α = 0.05%.

RESULTS

After 24 months, a significant crestal bone loss was observed for EMD (1.01 mm; p = 0.049) but not for OFD (0.14 mm; p = 0.622). However, no differences were detected between groups (p = 0.37). Reduction of the bone defect depth was significant for OFD (0.70 mm; p = 0.005) but not for EMD (0.04 mm; p = 0.86), while no differences were detected between them (p = 0.87). Both EMD (0.69°; p = 0.82) and OFD (5.71°; p = 0.24) showed an improvement in defect angle measurements but no significant differences were observed after 24 months or between the groups (p = 0.35).

CONCLUSION

Linear radiographic analysis was not able to demonstrate superiority of EMD treated infrabony defects when compared to ODF after 24 months.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02195765. Registered 17 July 2014.

Comparison of treatment effects of guided tissue regeneration on infrabony lesions between animal and human studies: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

For ethical reasons it is becoming increasingly more difficult to obtain, from clinical studies, histological data on infrabony defects treated with guided tissue regeneration (GTR) techniques. The aim of this systematic review was to find the value of extrapolating animal data on treatment of periodontal infrabony lesions, using GTR only or GTR + bone grafts, to human clinical results.

MATERIAL AND METHODS

Searches of the PubMed and Cochrane databases were combined with hand searching of articles published from 1 January 1969 to 1 August 2012. The search included any type of barrier membrane, with or without grafted materials, used to treat periodontal infrabony lesions. All studies with histological or re-entry methodology outcome parameters that evaluated bone-filling and/or new-cementum-formation ratios from a defect depth were collected. When comparing animal and human outcomes, a meta-analysis was used to evaluate the bone-filling ratio, but only a descriptive analysis of the histological studies was performed.

RESULTS

In total, 22 studies were selected for the meta-analysis. In the GTR + bone graft groups the weighted-average bone-filling ratios were 52% (95% CI: 18-85%) in animals and 57% (95% CI: 30-83%) in humans, which were not statistically significantly different (p = 0.825). Similar results were found in the GTR-only groups, in which the weighted-average bone-filling ratios were 54% (95% CI: 37-72%) in animals and 59% (95% CI: 42-77%) in humans (p = 0.703). New-cementum formation of GTR only and GTR + bone grafts showed comparable ratio outcomes, and both were superior to the control group in animals only (p = 0.042).

CONCLUSION

Although quality assessments differed between animal and human studies, our analysis indicated that animal models and human results showed similar bone-filling ratios in infrabony defects treated with GTR only or with GTR + bone grafting.

Nano-crystalline hydroxyapatite bone graft combined with bioresorbable collagen membrane in the treatment of periodontal intrabony defects: A randomized controlled clinical trial

Aim:

To evaluate the clinical outcome of nanocrystalline hydroxyapatite (NcHA) bonegraft (Sybograf^®) in combination with collagen membrane (PerioCol^®) compared with open flap debridement (OFD) only in the treatment of intrabony periodontal defects.

Materials and Methods:

Eighteen intrabony defects in 16 systemically healthy patients aged between 25-65 years, were randomly assigned to test and control groups. The Plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession were recorded at baseline, and were reevaluated at 6 months. In addition to this, radiographic bone fill was assessed using digital software. At the test site NcHA bone graft and collagen membrane was placed, whereas at the control site only, OFD was done. Recall appointments were made at 7^th day, 1^st month, 3^rd month, and 6^th month.

Results:

The data were subjected to statistical analysis using the Mann-Whitney ‘U’ Test and Wilcoxon signed rank sum test. In the control group, the mean reduction of PPD was 3.22±1.09 mm and CAL gain was 2.78±1.09 mm. In the test group, the mean PPD reduction of 4.33±0.5 mm and mean gain in CAL was 3.78±0.66 mm at 6 months. The mean increase in gingival recession was 0.55±0.72 mm in test and 0.44±0.52 mm in control group.

Conclusion:

The NcHA bone graft in combination with collagen membrane demonstrated better clinical outcomes compared with OFD alone.

Clinical and radiographic evaluation of Nano-crystalline hydroxyapatite bone graft (Sybograf) in combination with bioresorbable collagen membrane (Periocol) in periodontal intrabony defects

Background:

Nanosized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties. Nanocrystalline Hydroxyapatite (NcHA) bind to bone and stimulate bone healing by stimulation of osteoblast activity. The present study aims to explore the clinical and radiographical outcome of NcHA bonegraft (Sybograf^®) with collagen membrane (Periocol^®), in comparison with open flap debridement (OFD), in the treatment of intrabony periodontal defects.

Materials and Methods:

A parallel-group, randomized, controlled clinical trial was designed to conduct the study. Eighteen intrabony defects in 14 systemically healthy patients aged between 25 to 65 years were randomly assigned to test and control group. The plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession (REC) were recorded at baseline, and were reevaluated at 6 months. In addition to this, radiographic bone fill was assessed using digital software. At the test site, NcHA bone graft and collagen membrane was placed, whereas at the control site, only OFD was done. Recall appointments were made at 7 days, 30 days, and then at 3 months and 6 months.

Results:

The data were subjected to statistical analysis using the Mann-Whitney ‘U’ Test and Wilcoxon signed rank sum test. In the control group, the mean reduction of PPD was 3.22±1.09 mm (P=0.007) and CAL gain was 2.77±1.09 mm (P=0.007). In the test group, the mean PPD reduction of 4.33±0.5 mm (P=0.006) and mean gain in CAL was 3.77±0.66 mm (P=0.006) at 6 months. The mean increase in REC was 0.55±0.72 mm (P=0.025) in test, and 0.44±0.52 mm (P=0.046) in control group. The mean gain in radiographic defect fill was 2.07±0.67 mm (P=0.008) in test and 0.91±0.21 mm (P=0.007) in control group.

Conclusion:

The nanocrystalline hydroxyapatite bone graft in combination with collagen membrane demonstrated clinical advantages beyond that achieved by OFD alone.

Advanced reconstructive technologies for periodontal tissue repair

Reconstructive therapies to promote the regeneration of lost periodontal support have been investigated through both preclinical and clinical studies. Advanced regenerative technologies using new barrier-membrane techniques, cell-growth-stimulating proteins or gene-delivery applications have entered the clinical arena. Wound-healing approaches using growth factors to target the restoration of tooth-supporting bone, periodontal ligament and cementum are shown to significantly advance the field of periodontal-regenerative medicine. Topical delivery of growth factors, such as platelet-derived growth factor, fibroblast growth factor or bone morphogenetic proteins, to periodontal wounds has demonstrated promising results. Future directions in the delivery of growth factors or other signaling models involve the development of innovative scaffolding matrices, cell therapy and gene transfer, and these issues are discussed in this paper.

Role of space provision in regeneration of localized two-wall intrabony defects using periosteal pedicle graft as an autogenous guided tissue membrane

BACKGROUND

Marginal pedicle periosteum (MPP) has been used as a rigid membrane in guided tissue regeneration (GTR) for osseous defects. The present study aims to study the effect of space provision by an alloplastic graft material in bone defect area (BDA) reduction of 2-wall defects.

METHODS

Twenty interproximal intrabony 2-wall defects in healthy non-smoking patients with chronic periodontitis were randomly divided in control (group 1, periosteum alone) and experimental (group 2, periosteum with alloplastic graft material) groups. Measurements of probing depth (PD), clinical attachment level (CAL), and radiographic BDA were done at the baseline and 6-month postoperative evaluations.

RESULTS

The 6-month postoperative assessment showed clinical and radiographic improvements with PD reduction, CAL gain, and changes in BDA in both groups, which was statistically significant compared with baseline (P <0.05). However, BDA reduction was statistically greater in group 2 (48.88% ± 18.61%) compared with group 1 (14.08% ± 12.97%) at the 6-month follow-up (P = 0.009).

CONCLUSION

Within the limitations of this study, it can be concluded that space provision by an alloplastic graft material increases the regenerative potential of MPP as a GTR membrane and results in increased defect fill.

Quantitative analysis of bone density in direct digital radiographs evaluated by means of computerized analysis of digital images

OBJECTIVES

minimal density variations of mineralized tissues can be reliably detected with quantitative image subtraction analysis. The aim of this study was to evaluate quantitative variations of in vitro mineral density by varying the exposure time of direct digital radiographs using a computer assisted densitometric image analysis (CADIA) program.

METHODS

in a human mandibular segment a three-wall periodontal defect was created mesial to a molar. Bone chips were created from the marrowbone of the same mandible with masses of 1 to 5 mg. A triplicate radiograph of the defect was taken as a baseline for seven different exposure times. The bone chips were inserted into the defect and another triplicate series of radiographs for the seven exposure times were taken as follow-up images. The images were analysed using CADIA software to detect variations in bone density.

RESULTS

the results of CADIA revealed increased density when the size of the inserted bone chip increased. The 2 mg chip was underestimated owing to mass reduction during insertion. The regression line of the CADIA values was consistent with the weight of the bone chips of 1, 3, 4 and 5 mg. The exposure time f6 (0.178 s) showed the best correlation with the bone chip weight. Loss of information in the images occurred when the exposure time exceeded the sensor's latitude.

CONCLUSIONS

CADIA analysis is a reliable and sensitive tool for detecting subtle bone density variations. More reliable results are obtained with increased exposure time; however, excessive exposure should be avoided.

Clinical evaluation of regenerative potential of type I collagen membrane along with xenogenic bone graft in the treatment of periodontal intrabony defects assessed with surgical re-entry and radiographic linear and densitometric analysis

BACKGROUND AND OBJECTIVES

The primary goal of periodontal therapy is to restore the tooth supporting tissues lost due to periodontal disease. The aim of the present study was to compare the efficacy of combination of type I collagen (GTR membrane) and xenogenic bone graft with open flap debridement (OFD) in treatment of periodontal intrabony defects.

MATERIALS AND METHODS

Twenty paired intrabony defects were surgically treated using split mouth design. The defects were randomly assigned to treatment with OFD + collagen membrane + bone graft (Test) or OFD alone (Control). The clinical efficacy of two treatment modalities was evaluated at 9 month postoperatively by clinical, radiographical, and intrasurgical (re-entry) parameters. The measurements included probing pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), bone fill (BF), bone density (BD) and intra bony component (INTRA).

RESULTS

The mean reduction in PD at 0-9 month was 3.3±0.82 mm and CAL gain of 3.40±1.51 mm occurred in the collagen membrane + bone graft (Test) group; corresponding values for OFD (Control) were 2.20±0.63 mm and 1.90±0.57 mm. Similar pattern of improvement was observed when radiographical and intra-surgical (re-entry) post operative evaluation was made. All improvement in different parameters was statistically significant (P< 0.01).

INTERPRETATION AND CONCLUSION

Treatment with a combination of collagen membrane and bone graft led to a significantly more favorable clinical outcome in intrabony defects as compared to OFD alone.

Comparison of injectable calcium phosphate bone cement grafting and open flap debridement in periodontal intrabony defects: a randomized clinical trial

BACKGROUND

Regeneration of lost periodontium is the ultimate goal of periodontal therapy. Bone grafts, guided tissue regeneration, and application of growth factors are used for periodontal regeneration. This study aimed to evaluate the clinical efficacy of a new, injectable calcium phosphate bone cement (CPC) in human periodontal intrabony defects.

METHODS

Thirty subjects (mean age, 53.4 +/- 9.1 years) with periodontitis and narrow intrabony defects were enrolled in the study. Subjects were classified randomly into the CPC graft group (N = 15) or the open flap debridement (OFD) alone group (N = 15). Clinical measurements were performed at baseline and at 3, 6, 9, and 12 months; radiographs were taken at baseline, 2 weeks, and 6 and 12 months after surgery. The Student t test was used for statistical analysis.

RESULTS

In the CPC group, six cases showed exposure or loss of the CPC within 12 months, whereas the remaining nine cases (CPC-R group) showed no adverse reaction, including infection or suppuration. Overall, CPC-R and OFD treatment groups exhibited a significant reduction in probing depth and a significant gain in clinical attachment level at 3, 6, 9, and 12 months compared to baseline values. However, there were no significant differences in any of the clinical parameters between the groups. In the CPC-R group, radiographic bone level gain appeared to be greater than in the OFD group.

CONCLUSIONS

The present study failed to demonstrate any superior clinical outcomes for the CPC group compared to the OFD group; however, radiographs revealed more favorable results in the CPC-R group. The filling volume and stiffness of CPC may compromise the clinical outcomes for periodontal intrabony defects.

Bioactive ceramic filler in the treatment of severe osseous defects: 12-month results

BACKGROUND

Bioactive ceramic fillers are synthetic materials for medical use with the potential to enhance bone formation. The purpose of this study was to evaluate the clinical effectiveness of a bioactive ceramic filler in the treatment of teeth with poor prognosis because of deep osseous defects and increased tooth mobility.

METHODS

Nineteen patients, 35 to 75 years of age, who presented with one proximal intrabony periodontal defect with vertical radiographic bone loss >or=3 mm were included. After initial therapy, defects were assigned randomly to a test (12 defects) or control (seven defects) procedure. Following flap reflection and root planing, test defects were filled with a bioactive ceramic filler. Mucoperiosteal flaps were replaced and sutured, and a periodontal dressing was applied. All patients received postoperative analgesics, rinsed twice daily with chlorhexidine, and were seen 2 weeks postoperatively for suture removal. Postoperative deplaquing and reinstruction in home care were performed at weekly intervals during the first month, and at 3, 6, and 12 months. At baseline and at 6 and 12 months, dental plaque, bleeding on probing (BOP), probing depth (PD), and probing attachment level (PAL) were assessed, and standardized radiographs were taken.

RESULTS

The test and control groups showed similar periodontal status at baseline, with no significant differences in clinical or radiographic parameters. Plaque and BOP showed a non-significant deterioration over time. PD was reduced significantly in experimental and control sites following treatment (P <0.001), but there was no significant between-group difference (P = 0.793). For PAL and radiographic bone levels, no overall within- or between-group differences were detected.

CONCLUSION

The use of bioactive ceramic filler in combination with open debridement provided no significant beneficial effect over open debridement alone in the treatment of teeth with deep intraosseous defects, severe bone loss, and hypermobility.

Platelet-derived growth factor stimulates bone fill and rate of attachment level gain: results of a large multicenter randomized controlled trial

BACKGROUND

Growth factors are generally accepted to be essential mediators of tissue repair via well-established mechanisms of action that include stimulatory effects on angiogenesis and cellular proliferation, ingrowth, differentiation, and matrix biosynthesis. The aim of this study was to evaluate in a large-scale, prospective, blinded, and randomized controlled clinical trial the safety and effectiveness of purified recombinant human platelet-derived growth factor (rhPDGF-BB) mixed with a synthetic beta-tricalcium phosphate (beta-TCP) matrix for the treatment of advanced periodontal osseous defects at 6 months of healing.

METHODS

Eleven clinical centers enrolled 180 subjects, each requiring surgical treatment of a 4 mm or greater intrabony periodontal defect and meeting all inclusion and exclusion criteria. Subjects were randomized into one of three treatment groups: 1) beta-TCP + 0.3 mg/ml rhPDGF-BB in buffer; 2) beta-TCP + 1.0 mg/ml rhPDGF-BB in buffer; and 3) beta-TCP + buffer (active control). Safety data were assessed by the frequency and severity of adverse events. Effectiveness measurements included clinical attachment levels (CAL) and gingival recession (GR) measured clinically and linear bone growth (LBG) and percent bone fill (% BF) as assessed radiographically by an independent centralized radiology review center. The area under the curve (AUC), an assessment of the rate of healing, was also calculated for CAL measurements. The surgeons, clinical and radiographic evaluators, patients, and study sponsor were all masked with respect to treatment groups.

RESULTS

CAL gain was significantly greater at 3 months for group 1 (rhPDGF 0.3 mg/ml) compared to group 3 (beta-TCP + buffer) (3.8 versus 3.3 mm; P = 0.032), although by 6 months, this finding was not statistically significant (P = 0.11). This early acceleration of CAL gain led to group 1 exhibiting a significantly greater rate of CAL gain between baseline and 6 months than group 3 as assessed by the AUC (68.4- versus 60.1-mm weeks; P = 0.033). rhPDGF (0.3 mg/ml)-treated sites also had significantly greater linear bone gain (2.6 versus 0.9 mm, respectively; P < 0.001) and percent defect fill (57% versus 18%, respectively; P < 0.001) than the sites receiving the bone substitute with buffer at 6 months. There was less GR at 3 months in group 1 compared to group 3 (P = 0.04); at 6 months, GR for group 1 remained unchanged, whereas there was a slight gain in gingival height for group 3 resulting in comparable GR. There were no serious adverse events attributable to any of the treatments.

CONCLUSIONS

To our knowledge, this study is the largest prospective, randomized, triple-blinded, and controlled pivotal clinical trial reported to date assessing a putative periodontal regenerative and wound healing therapy. The study demonstrated that the use of rhPDGF-BB was safe and effective in the treatment of periodontal osseous defects. Treatment with rhPDGF-BB stimulated a significant increase in the rate of CAL gain, reduced gingival recession at 3 months post-surgery, and improved bone fill as compared to a beta-TCP bone substitute at 6 months.

Periodontal diseases

The periodontal diseases are highly prevalent and can affect up to 90% of the worldwide population. Gingivitis, the mildest form of periodontal disease, is caused by the bacterial biofilm (dental plaque) that accumulates on teeth adjacent to the gingiva (gums). However, gingivitis does not affect the underlying supporting structures of the teeth and is reversible. Periodontitis results in loss of connective tissue and bone support and is a major cause of tooth loss in adults. In addition to pathogenic microorganisms in the biofilm, genetic and environmental factors, especially tobacco use, contribute to the cause of these diseases. Genetic, dermatological, haematological, granulomatous, immunosuppressive, and neoplastic disorders can also have periodontal manifestations. Common forms of periodontal disease have been associated with adverse pregnancy outcomes, cardiovascular disease, stroke, pulmonary disease, and diabetes, but the causal relations have not been established. Prevention and treatment are aimed at controlling the bacterial biofilm and other risk factors, arresting progressive disease, and restoring lost tooth support.

Long-term stability of periodontal conditions achieved following guided tissue regeneration with bioresorbable membranes: case series results after 6-7 years

OBJECTIVES

To evaluate the results of guided tissue regeneration (GTR) treatment of intrabony defects with bioresorbable membranes after 6-7 years, and to disclose factors that may influence the long-term outcome of the treatment.

METHODS

Twenty-five defects in 19 patients were treated by means of polylactic acid/citric acid ester copolymer bioresorbable membranes. At baseline and after 1 and 6-7 years, the following parameters were recorded: (1) probing pocket depth (PPD), (2) gingival recession (REC), (3) probing attachment level (PAL)=PPD+REC, (4) presence/absence of plaque (PI), (5) presence/absence of bleeding on probing (BOP). Smoking habits and frequency of dental-control visits were also recorded. Significance of differences between categorical variables was evaluated with McNemar's test, and between numerical variables with the t-test for paired observations. Generalized linear models were constructed to evaluate the influence of various factors on PAL gain and PPD changes from 1 to 6-7 years. Association of smoking, frequency of dental controls, oral hygiene, and BOP with sites losing > or =2 mm in PAL was evaluated with Fisher's exact test.

RESULTS

At baseline, a mean PPD of 8.7+/-1.1 mm and a mean PAL of 9.8+/-1.5 mm was recorded. Statistically significant clinical improvements were observed at 1 and 6-7 years after GTR treatment. An average residual PPD of 3.8+/-1.1 mm and a mean PAL gain of 3.8+/-1.4 mm were observed after 1 year. After 6-7 years the corresponding values were 4.7+/-1.3 and 3.6+/-1.4 mm, respectively. There were no statistically significant differences between the 1- and the 6-7-year values. At the 6-7-year control, only 16% of the sites had lost > or =2 mm (maximum 3 mm), of the PAL gain obtained 1 year after GTR treatment. None of the sites had lost all of the attachment gained 1 year after treatment. Smoking, frequency of dental controls, oral hygiene, and BOP did not seem to influence the change of PPD and PAL gain, or the stability of PAL gain (i.e. losing PAL or not) from 1 to 6-7 years from treatment.

CONCLUSION

Clinical improvements achieved by GTR treatment of intrabony defects by means of bioresorbable membranes can be maintained on a long-term basis.

Smoking affects the outcome of guided tissue regeneration with bioresorbable membranes: a retrospective analysis of intrabony defects

OBJECTIVES

To disclose factors that may influence the results of guided tissue regeneration (GTR) treatment in intrabony defects with bioresorbable membranes.

METHODS

Forty-seven intrabony defects in 32 patients were treated by means of polylactic acid/citric acid ester copolymer bioresorbable membranes. At baseline and after 1 year, the following parameters were recorded: (1) probing pocket depth (PPD), (2) gingival recession (REC), (3) probing attachment level (PAL)=PPD+REC, (4) presence/absence of plaque (PI), (5) presence/absence of bleeding on probing (BOP) and (6) intrabony component (IC) configuration (i.e. primarily presence of one, two, or three bone walls). Occurrence of membrane exposure and smoking habits were also recorded. Significance of differences between categorical variables was evaluated with McNemar's test, and between numerical variables with the t-test for paired observations. Generalized linear models were constructed to evaluate the influence of various factors on PAL gain and PPD after 1 year, including in the analysis only one defect per patient (i.e. 32 defects) chosen at random. Odds ratios were calculated using the Mantel-Haenszel method. Differences between smokers and non-smokers were evaluated by means of Pearson's chi2 and Student's t-test for non-paired observations.

RESULTS

At baseline, a mean PPD of 8.6+/-1.1 mm and a mean PAL of 9.8+/-1.6 mm was recorded. Statistically significant clinical improvements were observed 1 year after GTR treatment. An average residual PPD of 3.7+/-1.1 mm and a mean PAL gain of 3.8+/-1.5 mm were recorded. IC configuration and exposure of the membrane did not seem to influence the results, while a negative effect of smoking on the clinical parameters was observed. Smokers gained approximately 1 mm less in PAL than non-smokers (3.2+/-1.4 versus 4.3+/-1.3, respectively; p=0.03) and had approximately seven times less chances to gain 4 mm in PAL as compared with patients who did not smoke (odds ratio: 0.15). PPD reduction was less pronounced in smokers than in non-smokers (4.5+/-0.7 versus 5.5+/-0.7, respectively; p<0.01), resulting in somewhat deeper residual PPD in smokers than in non-smokers (3.6+/-1.0 versus 3.4+/-1.1; p>0.05).

CONCLUSION

Smoking impairs the healing outcome of GTR treatment of intrabony defects with bioresorbable membranes.

The performance of projective standardization for digital subtraction radiography

OBJECTIVE

We sought to test the performance and robustness of projective standardization in preserving invariant properties of subtraction images in the presence of irreversible projection errors. Study design Twenty bone chips (1-10 mg each) were placed on dentate dry mandibles. Follow-up images were obtained without the bone chips, and irreversible projection errors of up to 6 degrees were introduced. Digitized image intensities were normalized, and follow-up images were geometrically reconstructed by 2 operators using anatomical and fiduciary landmarks. Subtraction images were analyzed by 3 observers.

RESULTS

Regression analysis revealed a linear relationship between radiographic estimates of mineral loss and actual mineral loss (R(2) = 0.99; P <.05). The effect of projection error was not significant (general linear model [GLM]: P >.05). There was no difference between the radiographic estimates from images standardized with anatomical landmarks and those standardized with fiduciary landmarks (Wilcoxon signed rank test: P >.05). Operator variability was low for image analysis alone (R(2) = 0.99; P <.05), as well as for the entire procedure (R(2) = 0.98; P <.05). The predicted detection limit was smaller than 1 mg.

CONCLUSIONS

Subtraction images registered by projective standardization yield estimates of osseous change that are invariant to irreversible projection errors of up to 6 degrees. Within these limits, operator precision is high and anatomical landmarks can be used to establish correspondence.

Effect of bone chip orientation on quantitative estimates of changes in bone mass using digital subtraction radiography

OBJECTIVES

To assess the effect of the orientation of arbitrarily shaped bone chips on the correlation between radiographic estimates of bone loss and true mineral loss using digital subtraction radiography.

METHODS

Twenty arbitrarily shaped bone chips (dry weight 1-10 mg) were placed individually on the superior lingual aspect of the interdental alveolar bone of a dry dentate hemi-mandible. After acquiring the first baseline image, each chip was rotated 90 degrees and a second radiograph was captured. Follow-up images were created without the bone chips and after rotating the mandible 0, 1, 2, 4, and 6 degrees around a vertical axis. Aluminum step tablet intensities were used to normalize image intensities for each image pair. Follow-up images were registered and geometrically standardized using projective standardization. Bone chips were dry ashed and analyzed for calcium content using atomic absorption.

RESULTS

No significant difference was found between the radiographic estimates of bone loss from the different bone chip orientations (Wilcoxon: P > 0.05). The correlation between the two series of estimates for all rotations was 0.93 (Spearman: P < 0.05). Linear regression analysis indicated that both correlates did not differ appreciably ( and ).

CONCLUSION

It is concluded that the spatial orientation of arbitrarily shaped bone chips does not have a significant impact on quantitative estimates of changes in bone mass in digital subtraction radiography. These results were obtained in the presence of irreversible projection errors of up to six degrees and after application of projective standardization for image reconstruction and image registration.

Long-term results of guided tissue regeneration therapy in the treatment of class II furcation defects: a randomized clinical trial

BACKGROUND

The purpose of this study was to evaluate the results after guided tissue regeneration (GTR) using a bioabsorbable membrane in Class II furcation defects in mandibular molars over a 24-month period.

METHODS

Nine patients with 2 comparable Class II furcation defects were included. The defects in each patient were randomly assigned to either test (GTR) or control (open flap debridement) group. Clinical measurements and standardized radiographs were taken at baseline, and at 6, 12, 18, and 24 months. The radiographs were analyzed by subtraction radiography.

RESULTS

There were significant probing depth reductions for both test and control groups (P < 0.007, P < 0.0005, respectively); however the differences between groups were not significant at any examination. The intra-group and inter-group differences in the vertical clinical attachment level gain were not significant (P > 0.05). Over 24 months, a significant horizontal clinical attachment level gain was observed in the test group compared to control (P<0.03). In the test group, 2 sites showed complete closure, one was converted to Class I, and one tooth was lost due to root resorption. In the control group, 2 defects progressed to Class III over 24 months. At 6 months, the test group showed 0.14 mm of bone loss while the control group showed 0.86 mm of bone gain (P = 0.035). The inter-group differences were not significant at 12, 18, and 24 months. A significant bone height gain was observed in the test group at 24 months when compared to the values obtained after 6 months (P = 0.015).

CONCLUSION

GTR may provide a greater horizontal clinical attachment level gain with the possibility of complete closure of some defects and stability over time.