Immunogenic effects of enamel matrix derivative on human alveolar ridge mucosa-derived vascular endothelial cells under lipopolysaccharide stimulation.

Early peri-implant disease detection remains difficult. Enamel matrix derivative (EMD), which is used for periodontal tissue regeneration, promotes leukocyte chemotactic factor and adhesion molecule expression in vascular endothelial cells. We hypothesized that stimulating vascular endothelial cells with EMD would induce an inflammatory response in the peri-implant mucosa, enabling early peri-implant infection detection. To verify this hypothesis, we assessed the intercellular adhesion between human alveolar ridge mucosa-derived vascular endothelial cells (ARMEC) stimulated with lipopolysaccharide (LPS) and EMD and human periodontal ligament-derived vascular endothelial cells (PDLEC). Leukocyte chemotactic factors and cell adhesion molecules were investigated and we established an experimental model of peri-implant disease by stimulating ARMEC (representing the peri-implant mucosa) with Porphyromonas gingivalis-derived LPS. ARMEC and PDLEC were obtained from patients (n = 6) who visited the Nippon Dental University Niigata Hospital. The cells were divided into four subcategories, each cultured with: LPS (1 µg/mL), EMD (100 µg/mL), LPS + EMD, and pure medium. Cell viability, leukocyte chemotactic factor (interleukin-8: IL-8), adhesion molecules (intercellular adhesion molecule-1: ICAM-1), tight junction protein gene expression (zonula occludens-1: ZO-1 and Occludin), and transendothelial electrical resistance (TEER) was then determined. LPS reduced ARMEC viability, whereas simultaneous stimulation with EMD improved it. LPS and EMD stimulation enhanced IL-8 and ICAM-1 gene expression, suppressed TEER, and decreased ZO-1 and Occludin expression levels compared to that with stimulation with LPS alone. EMD stimulates leukocyte migration, increase vascular permeability, and trigger an immune response in the peri-implant mucosa, thus facilitating the early detection and treatment of peri-implant disease.

Long-term results of regenerative treatment of intrabony defects: a cohort study with 5-year follow-up.

BACKGROUND: The aim of this retrospective cohort study was to evaluate the long-term clinical and radiographic outcomes and survival of teeth in periodontal regenerative treatment of intrabony defects using combined enamel matrix protein derivative (EMD) and deproteinized porcine bone mineral (DPBM) compared to EMD alone. METHODS: A total of 333 intrabony defects in 176 patients (mean age: 54.7 ± 8.9 years) were followed-up for 58.6 ± 11.2 (range, 25-78) months after periodontal regenerative treatment. Changes in clinical (pocket probing depth and clinical attachment level) and radiographic (defect depth and defect width) parameters were analyzed using serial periapical radiographs. Kaplan-Meier and multivariate Cox proportional-hazards regression analyses for tooth loss were also performed. RESULTS: Compared to periodontal surgery with EMD alone with a mean follow-up of 5 years, combined EMD and DPBM showed significantly better gain in clinical attachment level (EMD and DPBM: 2.8 ± 2.3 mm vs. EMD alone: 2.2 ± 2.2 mm) and reduction in probing pocket depth (EMD and DPBM: 2.8 ± 1.8 mm vs. EMD alone: 2.3 ± 1.8 mm), defect depth (EMD and DPBM: 2.5 ± 2.4 mm vs. EMD alone: 2.0 ± 2.4 mm) and defect width (EMD and DPBM: 0.6 ± 1.0 mm vs. EMD alone: 0.2 ± 1.3 mm). The overall survival rates of the teeth were 91.48% and 95.20% in the patient- and tooth-based analyses, respectively, showing no statistically significant difference. CONCLUSIONS: Within the limitations of the current study, combined EMD and DPBM offered additional clinical and radiographic benefits over a mean of 5 years compared to EMD alone. However, tooth loss did not differ significantly between the two groups. CLINICAL RELEVANCE: Compared to EMD alone, combined EMD and DPBM for intrabony defects has additional clinical advantages; however, patient- and tooth-related risk factors must be considered when performing periodontal regenerative surgery.

Effects of CEM cement and emdogain on proliferation and differentiation of human stem cells from the apical papilla: a comparative in vitro study.

OBJECTIVES: This study compared the effects of calcium-enriched mixture (CEM) cement, Emdogain (EMD), and their combination (CEM/Emdogain) on the differentiation and proliferation of stem cells from the apical papilla (SCAPs). METHODS: In this in vitro, experimental study, SCAPs were isolated from two sound immature impacted third molars and cultured. After ensuring their stemness by detecting cell surface markers they were exposed to CEM cement, Emdogain, and CEM cement coated with Emdogain for 24 and 72 h. The control cells did not undergo any intervention. Cell viability [by methyl thiazolyl tetrazolium (MTT) assay], expression of odontogenic differentiation genes [by quantitative reverse-transcription polymerase chain reaction (qRT-PCR)], and alkaline phosphatase (ALP) activity (by ALP staining kit) were evaluated. Data were analyzed by one-way ANOVA, t-test, and Mann-Whitney test (α = 0.05). RESULTS: Cell viability in the CEM cement and CEM/Emdogain groups decreased compared with the control group at 72 h (P < 0.05). Expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP) genes, and ALP activity significantly increased in all three experimental groups compared with the control group at both 24 and 72 h. This increase was substantially more significant in CEM/Emdogain group (P > 0.05). The number of mineralized nodules significantly increased in all groups at 72 h, with a higher rate in the CEM/Emdogain group. CONCLUSION: All biomaterials increased the differentiation of SCAPs, expression of odontogenic differentiation genes, and ALP activity, but CEM/Emdogain was considerably more effective for this purpose.

Amelogenesis imperfecta in a Chinese family resulting from a FAM83H variation and the effect of FAM83H on the secretion of enamel matrix proteins.

OBJECTIVES: To investigate the variant of an amelogenesis imperfecta (AI) family and to explore the function of the FAM83H (family with sequence similarity 83 member H) in the enamel formation. MATERIALS AND METHODS: We investigated a five-generation Chinese family diagnosed with AI; clinical data was collected, whole-exome sequencing (WES) was conducted to explore the pathogenic gene and variants and Sanger sequencing was used to verify the variants. The three-dimensional protein structures of wild-type and mutant FAM83H were predicted using alpha fold 2. To study the possible regulatory function of Fam83h on amelogenesis, immunolocalization was performed to observe the expression of Fam83h protein in Sprague-Dawley rat postnatal incisors. The mRNA and protein level of amelogenin, enamelin, kallikrein-related peptidase-4 and ameloblastin were also detected after the Fam83h was knocked down by small interfering RNA (siRNA) in HAT-7 cells. RESULTS: A known nonsense variant (c.973 C > T) in exon 5 of FAM83H gene was found in this family, causing a truncated protein (p.R325X). Immunolocalization of Fam83h in Sprague-Dawley rat postnatal incisors showed that Fam83h protein expression was detected in presecretory and secretory stages. When Fam83h expression was reduced by siRNA, the expression of amelogenin, enamelin, kallikrein-related peptidase-4 decreased. However, the expression of ameloblastin increased. CONCLUSIONS: FAM83H gene variant (c.973 C > T) causes AI. FAM83H regulates the secretion of enamel matrix proteins and affects ameloblast differentiation. CLINICAL RELEVANCE: This study provided that FAM83H variants could influence enamel formation and provided new insights into the pathogenesis of AI.

Effects of Enamel Matrix Derivative on Cell Spheroids Made of Stem Cells Obtained from the Gingiva on Osteogenic Differentiation.

Background and Objectives: A derivative of the enamel matrix was used to speed up periodontal regeneration, including the formation of new cementum, alveolar bone, and periodontal ligament. In this study, human gingiva-derived stem cell-derived cell spheroids were used to assess the effects of an enamel matrix derivative on cell viability, osteogenic differentiation, and mineralization. Materials and Methods: Human gingiva-derived stem cells were used to create spheroids, which were then coupled with unloaded control groups and an enamel matrix derivative at a final concentration of 2.7, 27, 270, and 2700 µg/mL. The morphological examination of the created stem cell spheroids took place on days 1, 3, 5, and 7. The Live/Dead Kit assay was used to determine the qualitative viability of cells on days 3 and 7. Using the Cell Counting Kit-8, the quantitative vitality of the cell spheroids was assessed on days 1, 3, and 5. On days 7 and 14, alkaline phosphatase activity assays and Alizarin Red S staining were carried out to examine the osteogenic differentiation of the cell spheroids. RUNX2 and COL1A1 expression levels on days 7 and 14 were determined using real-time polymerase chain reaction. Results: The added enamel matrix derivative at the tested concentrations did not significantly alter the morphology of the applied stem cells' well-formed spheroids on day 1. On days 3 and 7, the majority of the spheroids' cells fluoresced green while they were being cultivated. Alkaline phosphatase activity data revealed a substantial rise in the 2700 µg/mL group on day 7 when compared to the unloaded control (p < 0.05). On days 7 and 14, calcium deposits were distinctly seen in each group. In the 27 and 2700 µg/mL groups, the treatment with the enamel matrix derivative resulted in noticeably higher values for the Alizarin Red S staining (p < 0.05). qPCR results showed that adding an enamel matrix derivative to the culture of the 27 µg/mL group raised the level of RUNX2 mRNA expression. Conclusions: These results lead us to the conclusion that a derivative of the enamel matrix may be used to promote osteogenic differentiation in stem cell spheroids.

Effect of biodentine coated with emdogain on proliferation and differentiation of human stem cells from the apical papilla.

BACKGROUND: This study assessed the effect of Biodentine coated with Emdogain (Biodentine/Emdogain) on proliferation and differentiation of human stem cells from the apical papilla (SCAPs). METHODS AND RESULTS: In this in vitro, experimental study, SCAPs were isolated from two immature impacted third molars and cultured. After ensuring the stemness of the cells by assessing the cell surface markers, they were exposed to Biodentine, Emdogain, and Biodentine/Emdogain for 24 and 72 h. The control cells did not receive any intervention. Cell viability was evaluated by the methyl thiazolyl tetrazolium assay. Expression of odontogenic differentiation genes was analyzed by the quantitative reverse transcription polymerase chain reaction. Alkaline phosphatase (ALP) activity was quantified by the respective kit. Data were analyzed by one-way ANOVA, t-test, and Mann-Whitney test (α = 0.05). Cell viability did not change after 24 h of exposure to biomaterials. At 72 h, the viability of the cells exposed to Biodentine and Biodentine/Emdogain decreased compared with the control group. The expression of dentin sialophosphoprotein, dentin matrix protein 1, and bone sialoprotein genes, and ALP activity significantly increased in all three experimental groups, compared with the control group at both 24 and 72 h; this increase was significantly greater in Biodentine/Emdogain group. The number of mineralized nodules significantly increased in all groups after 72 h with a greater rate in Biodentine/Emdogain group. CONCLUSIONS: All biomaterials increased the differentiation of SCAPs, expression of odontogenic genes, and ALP activity, but Biodentine/Emdogain was significantly more effective for this purpose.

Influence of aging on periodontal regenerative therapy using enamel matrix derivative: A 3-year prospective cohort study.

AIM: To investigate the influence of chronological aging on periodontal regenerative therapy (PRT) outcomes with enamel matrix derivative (EMD). MATERIALS AND METHODS: In total, 253 intra-bony defects (151 patients) including 44 furcation involvement were prospectively investigated for 3 years after regenerative therapy with EMD by evaluating probing pocket depth (PPD), clinical attachment level (CAL), and radiographic bone defect depth (RBD). The influence of age on these outcomes was assessed using multilevel regression analyses adjusting for confounders. RESULTS: Participants' mean age was 55.9 ± 12.3 years (range: 22-85). Baseline PPD, CAL, and RBD were 6.14 ± 1.82, 7.22 ± 2.14, and 5.08 ± 2.04 mm, respectively. Significant improvement was observed with PPD reductions of 2.84 ± 1.73 and 2.87 ± 1.87 mm, CAL gains of 2.40 ± 1.87 and 2.47 ± 1.89 mm, and RBD gains of 1.76 ± 1.98 and 2.39 ± 2.41 mm at 1- and 3-year examinations, respectively. At the 1-year examination, multivariate analysis revealed a significant negative association between age and improvement in PPD and CAL (coefficients: -0.13, -0.23 mm per 10 years). However, by the 3-year examination, no significant association was noted between age and improvement in PPD, CAL, or RBD. CONCLUSION: Although the statistical difference was detected with age at 1-year examination, PRT with EMD significantly improved clinical outcomes on long-term observation, irrespective of the patient's age. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000039846.

Enamel matrix derivative as an adjunct to minimally invasive non-surgical treatment of intrabony defects: A randomized clinical trial.

AIM: To compare the efficacy of minimally invasive non-surgical technique (MINST) with or without enamel matrix derivative (EMD) in the treatment of intrabony defects ≤7 mm. MATERIALS AND METHODS: Thirty-six patients were randomly assigned to the two groups. The control group received MINST, while the experimental MINST+EMD. Clinical measurements were recorded at baseline and at 6 and 12 months, and radiographic measurements were made at baseline and 12 months. RESULTS: All subjects completed the study, 18 in each group. Significant improvements were observed in both groups at 12 months (p < .001) with no differences in mean PD reduction (4.0 ± 1.4 vs. 4.2 ± 1.7 mm), CAL gain (3.5 ± 1.4 vs. 3.4 ± 1.6 mm), and defect resolution (1.9 ± 1.1 vs. 1.8 ± 0.9 mm) for the MINST and the MINST+EMD groups, respectively (p > .05). A trend for greater pocket closure (PD ≤4 mm and no BoP) was achieved with the application of EMD (77.8% vs. 55.6% sites), particularly for sites with baseline PD ≤8 mm (92.3% vs. 69.2% sites), accompanied by an increased number of successful composite outcome results (61.1% vs. 44.4% sites). CONCLUSIONS: MINST demonstrates significant improvements 12 months after treatment of intrabony defects ≤7 mm. The additional application of EMD does not further improve the mean clinical or radiographic outcomes. This study is registered in ClinicalTrials.gov (NCT03622255).

Enamel matrix derivative effects on palatal mucosa wound healing: Randomized clinical trial.

BACKGROUND: This study was conducted to evaluate the clinical, immunologic, and patient-centered outcomes of enamel matrix protein derivative (EMD) on excisional wounds in palatal mucosa. MATERIALS: Forty-four patients in need of ridge preservation were randomly allocated into two groups: control group (n = 22): open palatal wound after free gingival graft (FGG) harvest and EMD group (n = 22): open palatal wound after FGG harvest that received 0.3 ml of EMD. Clinical and patient-centered parameters were analyzed for 3 months post-treatment. Wound fluid levels of inflammatory markers were assessed 3 and 7 days postoperatively. RESULTS: No significant inter-group difference was observed in remaining wound area and re-epithelialization. EMD and control groups achieved wound closure and re-epithelialization 30 days postoperatively (p < .001), without inter-group differences. Similarly, number of analgesics and Oral Health Impact Profile scores did not present significant inter-group differences (p > .05). EMD appeared to selectively modulate wound fluid levels of monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, matrix metallopeptidase 9, and tissue inhibitor of metalloproteinases-2. CONCLUSION: Within the limits of the present study, it can be concluded that EMD application to excisional palatal wounds using the investigated protocol does not provide clinical healing benefits, despite an apparent modulation of selected inflammatory markers.

Medium- and long-term clinical benefits of periodontal regenerative/reconstructive procedures in intrabony defects: Systematic review and network meta-analysis of randomized controlled clinical studies.

BACKGROUND: Systematic reviews have established the short-term improvements of periodontal regenerative/reconstructive procedures compared to conventional surgical treatment in intrabony defects. However, a hierarchy of periodontal regenerative/reconstructive procedures regarding the medium- to long-term results of treatment does not exist. AIM: To systematically assess the literature to answer the focused question "In periodontitis patients with intrabony defects, what are the medium- and long-term benefits of periodontal regenerative/reconstructive procedures compared with open flap debridement (OFD), in terms of clinical and/or radiographic outcome parameters and tooth retention?". MATERIAL & METHODS: Randomized controlled clinical trials (RCTs), reporting on clinical and/or radiographic outcome parameters of periodontal regenerative/reconstructive procedures ≥3 years post-operatively, were systematically assessed. Clinical [residual probing pocket depth (PD) and clinical attachment level (CAL) gain, tooth loss] and radiographic [residual defect depth (RDD), bone gain (RBL)] outcome parameters were assessed. Descriptive statistics were calculated, and Bayesian random-effects network meta-analyses (NMA) were performed where possible. RESULTS: Thirty RCTs, presenting data 3 to 20 years after treatment with grafting, GTR, EMD, as monotherapies, combinations thereof, and/or adjunctive use of blood-derived growth factor constructs or with OFD only, were included. NMA based on 21 RCTs showed that OFD was clearly the least efficacious treatment; regenerative/reconstructive treatments resulted in significantly shallower residual PD in 4 out 8 comparisons [range of mean differences (MD): -2.37 to -0.60 mm] and larger CAL gain in 6 out 8 comparisons (range of MD: 1.26 to 2.66 mm), and combination approaches appeared as the most efficacious. Tooth loss after regenerative/reconstructive treatment was less frequent (0.4%) compared to OFD (2.8%), but the evidence was sparse. There were only sparse radiographic data not allowing any relevant comparisons. CONCLUSION: Periodontal regenerative/reconstructive therapy in intrabony defects results, in general, in shallower residual PD and larger CAL gain compared with OFD, translating in high rates of tooth survival, on a medium (3-5 years) to long-term basis (5-20 years). Combination approaches appear, in general, more efficacious compared to monotherapy in terms of shallower residual PD and larger CAL gain. A clear hierarchy could, however, not be established due to limited evidence.

Single flap approach with or without enamel matrix derivative in the treatment of severe supraosseous defects: a retrospective study.

AIM: To comparatively evaluate the clinical effectiveness of the single flap approach (SFA) with and without enamel matrix derivative (EMD) in the treatment of supraosseous defects (SDs) associated with deep pockets. MATERIALS AND METHODS: Twenty patients, each contributing one SD associated with a deep (≥ 6 mm) pocket and treated with buccal SFA either alone (SFA group; n = 10) or in combination with EMD (SFA+EMD group; n =10), were retrospectively selected. Clinical parameters (probing depth, PD; clinical attachment level, CAL; gingival recession, REC) had been assessed at pre-surgery and 12 months post-surgery. RESULTS: Complete wound closure was observed in 70% and 80% of defects treated with SFA and SFA+EMD, respectively. Treatments resulted in a significant PD reduction of 3.1±1.0 mm (p=0.005). In SFA+EMD group, 100% of closed pockets was obtained, while 90% of closed pockets was observed in SFA group. Both treatments resulted in a significant CAL gain of 2.1±0.9 mm and 1.9±1.7 mm in SFA and SFA+EMD group, respectively (p= 0.465). In both groups, REC significantly increased 1.0±1.1 mm in SFA group and 1.1±1.1 mm in SFA+EMD group (p= 0.722). CONCLUSIONS: Within their limits, the findings of present study suggest that SFA may represent a valuable option for the surgical treatment of SDs associated with deep pockets. EMD did not result in a significant clinical benefit to the procedure. CLINICAL RELEVANCE: SFA may represent a valuable option in obtaining pocket closure when treating SDs associated with deep residual pockets.

The Outcomes of Enamel Matrix Derivative on Periodontal Regeneration under Diabetic Conditions.

Background and Objectives: Enamel matrix derivative (EMD) is a biomaterial used for periodontal regenerative therapy due to its properties of stimulating cementum development and bone synthesis. Diabetes is a chronic condition that affects healing and predisposes to infection. The aim of this review was to evaluate the current studies available on the application and results of EMD for periodontal regenerative therapy under diabetic conditions. Materials and Methods: Five databases (PubMed, ResearchGate, Scopus, Web of Science and Google Scholar) were searched for relevant articles, using specific keywords in different combinations. The inclusion criteria were clinical trials, case reports, case studies, and animal studies published in English, where periodontal treatment for bone defects includes EMD, and it is performed under diabetic conditions. Results: Of the 310 articles resulted in search, five studies published between 2012 and 2020 met the inclusion criteria and were selected for the current review. In human studies, the use of EMD in infrabony defects showed favorable results at follow-up. In animal studies, periodontal regeneration was reduced in diabetic rats. Conclusions: EMD might promote bone healing when used under diabetic conditions for the regenerative periodontal therapy. Due to limited number of studies, more data are required to sustain the effects of EMD therapy in diabetic settings.

A 3-year prospective clinical and patient-centered trial on subepithelial connective tissue graft with or without enamel matrix derivative in Class I-II Miller recessions.

BACKGROUND AND OBJECTIVE: The study compared clinical and patient-centered outcomes of subepithelial connective tissue graft (CTG) with and without enamel matrix derivative (EMD) in the treatment of Class I-II Miller periodontal recession defects. MATERIAL AND METHODS: This prospective clinical study evaluated 80 patients over a 3 years follow-up in a private periodontal practice. A total of 144 maxillary and mandibular anterior teeth were divided into two groups: group 1 (CTG with EMD-80 teeth) and group 2 (CTG only-64 teeth). Recession (REC), keratinized tissue (KT) width, % root overage, patient-centered outcomes, and pain visual analog scale (P-VAS) were compared between the two groups. RESULTS: At 3 years follow-up at a patient level, statistically significant changes in REC were achieved in both group 1 (4.65 ± 1.84 to 0.39 ± 0.19 mm) and group 2 (4.43 ± 1.11 to 0.92 ± 0.43 mm). Complete root coverage (CRC) was achieved in 66.4% of group 1 and 50.1% of group 2. At both patient and tooth level, the 3-year outcomes were superior for group 1 compared with group 2 in terms of % root coverage, REC, and KT width. Clinical attachment loss (CAL) was reduced in group 1 compared with group 2 at the tooth level analysis only (<.01). Significantly less pain was reported using the pain visual analog Scale (P < .001) at the two weeks follow-up post-surgery in group 1. CONCLUSIONS: Addition of EMD results in improved root coverage outcomes and higher amounts of keratinized tissue width 36 months after treatment of multiple adjacent recessions on maxillary and mandibular anterior teeth. The adjunctive use of EMD also resulted in significantly reduced pain 14 days after the surgery.

Clinical outcomes of the entire papilla preservation technique with and without biomaterials in the treatment of isolated intrabony defects: A randomized controlled clinical trial.

AIM: This study compared the clinical efficacy of the entire papilla preservation technique (EPP) alone and in combination with enamel matrix proteins plus bovine-derived bone substitutes (EPP EMD + BS) in the treatment of isolated inter-dental intrabony defects. MATERIAL AND METHODS: Thirty patients, each with one isolated intrabony defect, were randomly assigned to EPP EMD + BS or EPP alone. Clinical outcomes were assessed 1-year post-surgery. RESULTS: Early healing phase was uneventful in all cases, and 100% primary wound closure was maintained throughout the study period. Intragroup differences between baseline and 1-year were statistically significant in both groups in terms of clinical attachment level (CAL) gain and probing depth (PD) reduction (p ≤ .001). No statistically significant differences were detected in gingival recession (REC) (p > .05). No statistically significant differences were detected in terms of CAL gain (6.3 ± 2.5 mm vs. 5.83 ± 1.12 mm), PD reduction (6.5 ± 2.65 mm vs. 6.2 ± 1.33 mm) or increase in gingival recession (0.2 ± 0.25 mm vs. 0.36 ± 0.54 mm) between the groups treated with EPP EMD + BS or EPP alone. CONCLUSIONS: Application of EPP with and without regenerative biomaterials resulted in significant amounts of CAL gain and PD reduction, with negligible increase in gingival recession. Within the limits of the present study, it can be concluded that the addition of regenerative biomaterials does not improve the clinical outcomes of EPP alone. NCT03923465.

Reptile enamel matrix proteins: Selection, divergence, and functional constraint.

The three major enamel matrix proteins (EMPs): amelogenin (AMEL), ameloblastin (AMBN), and enamelin (ENAM), are intrinsically linked to tooth development in tetrapods. However, reptiles and mammals exhibit significant differences in dental patterning and development, potentially affecting how EMPs evolve in each group. In most reptiles, teeth are replaced continuously throughout life, while mammals have reduced replacement to only one or two generations. Reptiles also form structurally simple, aprismatic enamel while mammalian enamel is composed of highly organized hydroxyapatite prisms. These differences, combined with reported low sequence homology in reptiles, led us to predict that reptiles may experience lower selection pressure on their EMPs as compared with mammals. However, we found that like mammals, reptile EMPs are under moderate purifying selection, with some differences evident between AMEL, AMBN, and ENAM. We also demonstrate that sequence homology in reptile EMPs is closely associated with divergence times, with more recently diverged lineages exhibiting high homology, along with strong phylogenetic signal. Lastly, despite sequence divergence, none of the reptile species in our study exhibited mutations consistent with diseases that cause degeneration of enamel (e.g. amelogenesis imperfecta). Despite short tooth retention time and simplicity in enamel structure, reptile EMPs still exhibit purifying selection required to form durable enamel.

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.

Enamel matrix derivative in liquid form as adjunct to natural bovine bone grafting at buccal bone dehiscence defects at implant sites: An experimental study in beagle dogs.

OBJECTIVES: To evaluate the effect of enamel matrix derivative in liquid form (EMD-liquid) as adjunct to grafting with natural bovine bone (NBB), on new bone formation and osseointegration in buccal dehiscence defects at dental implants. MATERIAL AND METHODS: In six beagles, 3 months after extraction of the mandibular premolars and first molars. Three titanium implants (3.3 Ø × 8.0 mm) were inserted, and dehiscence-type defects (mesiodistal width 3 mm × 5 mm depth) were created on their buccal aspect. The defects were randomly assigned to one of the following three treatment groups: Group 1: NBB, Group 2: NBB/EMD-L, Group 3: Control. All sites were covered with a collagen membrane. Histomorphometric measurements were performed after 3 months of healing. RESULTS: New bone area, bone-to-implant contact (BIC), and first BIC (fBIC) in the NBB and NBB/EMD-L groups were significantly greater than in the control group (p < .05). Further, f-BIC was at a significantly more coronal position in the NBB + EMD-liquid group (0.4 ± 0.1 mm) compared with the NBB group (1.2 ± 0.2 mm). CONCLUSIONS: Natural bovine bone grafting enhances bone regeneration and osseointegration at implants with buccal bone dehiscences compared with no grafting, and adjunct use of EMD-liquid appears to further enhance bone formation and osseointegration.

Early wound healing outcomes after regenerative periodontal surgery with enamel matrix derivatives or guided tissue regeneration: a systematic review.

BACKGROUND: Proper wound healing after regenerative surgical procedures is an essential issue for clinical success. Guided tissue regeneration (GTR) and application of enamel matrix derivatives (EMD) are common means to regenerate periodontal tissues. Both methods bear considerable advantages due to their special characteristics, but also go along with certain disadvantages. Today, there is no consensus in the literature whether GTR or EMD show better results regarding early wound healing, which is considered a crucial stage in periodontal regeneration. Therefore, the aim of the present systematic review was to compare the early wound healing after regenerative periodontal surgery with either EMD or GTR treatment. METHODS: An electronic literature search in PubMed was performed to identify randomized clinical trials (RCTs) or clinical trials (CTs) comparing regenerative surgery employing EMD and/or GTR in patients with chronic periodontitis. Among the finally included studies, a qualitative and quantitative data extraction regarding early wound healing parameters was performed. Primary outcome parameters were early wound healing index (EWH), flap dehiscence, membrane exposure, suppuration and abscess formation during the first 6 weeks. As secondary parameters, swelling and allergic reactions were assessed. RESULTS: Seven studies reporting 220 intrabony periodontal defects in 199 patients were analysed. Flap dehiscence was observed in two studies in 12% of the GTR treated sites and in 10.3% of those treated with EMD. Membrane exposure was evaluated in five studies and was registered in the 28.8% of the defects, while no dehiscence was reported on the EMD group. Swelling was reported only in one study in 8/16 GTR sites and 7/16 EMD sites. Due to considerable heterogeneity of parameters no meta-analysis was possible. CONCLUSIONS: Due to considerable heterogeneity of the published studies a clear beneficial effect of the EMD on the early wound healing outcomes after surgical treatment of periodontal intrabony defects cannot be confirmed. Standardized RCT studies are needed in order to allow for proper comparison of early wound healing after both types of surgical approaches.

Entire papilla preservation technique in the regenerative treatment of deep intrabony defects: 1-Year results.

AIM: This study evaluates the clinical outcomes of a novel tunnel-like surgical technique in the treatment of isolated deep intrabony defects. MATERIAL AND METHODS: Twelve patients presenting with at least one isolated deep intrabony defect received regenerative periodontal treatment with "entire papilla preservation (EPP)" technique. Access to the intrabony defect for debridement was provided by a bevelled vertical releasing incision positioned in the buccal gingiva of the neighbouring inter-dental space. Following the elevation of a buccal flap, an inter-dental tunnel was prepared undermining the defect-associated papilla. Granulation tissue was removed, root surfaces were carefully debrided and bone substitutes and enamel matrix derivative were applied. Microsurgical suturing technique was used for optimal wound closure. RESULTS: Early healing was uneventful in all cases, and 100% wound closure was maintained during the entire healing period. At 1-year, there was significant attachment gain of 6.83±2.51 mm (p<0.001). The 7±2.8 mm reduction in probing depth was also significant (p<0.001), which was associated with minimal increase in gingival recession (0.16±0.38 mm, p=0.166). CONCLUSIONS: Tunnel-like "EPP" technique may limit the risk of wound failure particularly in the early healing phase, thereby preventing exposure of regenerative biomaterials, possibly enhancing stabilization of blood clot in deep intrabony defects and leading to optimal clinical outcomes.

Healing of two-wall intra-bony defects treated with a novel EMD-liquid-A pre-clinical study in monkeys.

AIM: To investigate the effect of a novel enamel matrix derivative formulation (EMD-liquid or Osteogain) combined with an absorbable collagen sponge (ACS) on periodontal wound healing in intra-bony defects in monkeys. MATERIALS AND METHODS: Chronic two-wall intra-bony defects were created at the distal aspect of eight teeth in three monkeys (Macaca fascicularis). The 24 defects were randomly assigned to one of the following treatments: (i) open flap debridement (OFD) + ACS alone, (ii) OFD + Emdogain + ACS (Emdogain/ACS), (iii) OFD + Osteogain + ACS (Osteogain/ACS) or (iv) OFD alone. At 4 months, the animals were euthanized for histologic evaluation. RESULTS: Osteogain/ACS resulted in more consistent formation of cementum, periodontal ligament and bone with limited epithelial proliferation compared to OFD alone, Emdogain/ACS and OFD + ACS. Among the four treatment groups, the Osteogain/ACS group demonstrated the highest amount of regenerated tissues. However, complete periodontal regeneration was not observed in any of the defects in the four groups. CONCLUSIONS: The present findings indicate that in two-wall intra-bony defects, reconstructive surgery with Osteogain/ACS appears to be a promising novel approach for facilitating periodontal wound healing/regeneration, thus warranting further clinical testing.