Low Level Laser Therapy With an 810-nm Diode Laser Affects the Proliferation and Differentiation of Premature Osteoblasts and Human Gingival Fibroblasts In Vitro

Introduction: Photomodulation is a promising strategy for optimizing tissue healing, but its photomodulatory effects on the synergistic cellular metabolism of gingival and bony tissues remain largely unknown. The aim of the present study was to evaluate the photomodulatory effects of a diode laser (810 nm) on osteoblasts, HGFs and their co-cultures in vitro. Methods: Primary cultures of HGFs, cultures of immature osteoblastic cells (MG63) and their co-cultures were irradiated with a diode laser (810 nm), 15 J/cm². Cell cultures were examined for cellular proliferation (MTT assay), viability (FDA/PI staining) after 24, 48 and 72 hours and cell differentiation (qPCR of collagen type 1a - COL1a and alkaline phosphatase expressions - ALP) after 7 days. Results: Photomodulation with an 810-nm diode laser increased cell proliferation at all time points. COL1a gene expression increased both in HGF and co-cultures. ALP expression was up-regulated in osteoblastic cultures, but co-cultures with fibroblasts negated this response. Conclusion: The 810-nm diode laser positively affected cell proliferation and viability in all experimental groups. The statistically significant increased COL1a gene expression at 7 days after irradiation both in the irradiated HGF and co-cultures suggests that low-level laser therapy (LLLT) stimulated extracellular matrix (ECM) formation signaling in both cell types.

Dosage Effects of an 810 nm Diode Laser on the Proliferation and Growth Factor Expression of Human Gingival Fibroblasts

Introduction: A substantial amount of evidence supports the positive effect of photobiomodulation on the proliferation and differentiation of various cell types. Several laser wavelengths have been used for wound healing improvement, and their actual outcome depends on the settings utilized during irradiation. However, the heterogeneous wavelengths and laser settings applied in the existing literature make it difficult to draw solid conclusions and comparison of different studies. The aim of the present study is to evaluate and compare the effects of various doses of laser energy, provided by an 810 nm diode, on human gingival fibroblasts in terms of proliferation and expression of growth factors with a pivotal role in wound healing. Methods: Human gingival fibroblasts were cultured on plastic tissue culture and irradiated with 2, 4, 6 or 12 J/cm². The effects of the low-level laser therapy (LLLT) using an 810 nm diode laser on growth factor expression (EGF, TGF and VEGF) were evaluated by qPCR at 72 hours and 7 days after irradiation. Cell proliferation was evaluated at 24, 48 and 72 hours after LLLT using MTT assay. Results: Energy density of 12 J/cm² provoked irradiated gingival fibroblasts to demonstrate significantly higher proliferation as well as higher gene expression of Col1, VEGF and EGF. LLLT positive effects were obvious up to 7 days post-irradiation. Conclusion: LLLT with 810 nm presents beneficial effects on proliferation, collagen production and growth factor expression in human gingival fibroblast cells. The application of 12 J/cm² can be suggested as the optimal energy density for the enhancement of the wound healing process.

A randomized controlled clinical trial on the effectiveness of three different mouthrinses (chlorhexidine with or without alcohol and C31G), adjunct to periodontal surgery, in early wound healing

OBJECTIVES

The use of chlorhexidine (CHX) with or without alcohol has been recommended for a number of clinical applications. On the other hand, there is a plethora of widely subscribed antiseptics, such as agent C31G (alkyl dimethyl glycine/alkyl dimethyl amine oxide), which has not yet been evaluated postsurgically. The effectiveness of three different mouthrinses (CHX with and without alcohol, C31G) in plaque control and early wound healing was compared postoperatively.

MATERIALS AND METHODS

In this, randomized, double-blind, controlled clinical trial 42 patients were allocated to three groups assigned to 2 weeks rinsing after non-regenerative periodontal flap surgery with or without osseous surgery with C31G (group A), alcohol-free CHX 0.12% (group B) or alcohol-based CHX 0.12% (group C). At days 7 and 14, plaque and early wound healing indices were recorded. At day 14, total bacterial counts were estimated utilizing real-time quantitative polymerase chain reaction (qPCR). Statistics included linear and generalized linear mixed models.

RESULTS

At day 7, healing response was not significantly different among groups. At day 14, group A revealed the highest while group C demonstrated the lowest plaque index values (B vs A, odds ratio-OR = 0.18, p = 0.012; C vs A, OR = 0.01, p < 0.001; C vs B, OR = 0.06, p < 0.001). Group C demonstrated the lowest bacterial counts levels at day 14 (38.470 × 10⁶, 48.190 × 10⁶, and 3.020 × 10⁶ for groups A, B, and C, respectively). At day 14, healing was significantly better in group C compared to B (p = 0.007). Group A showed no significant differences compared to other groups.

CONCLUSIONS

(1) The presence of alcohol may increase the effectiveness of CHX in early wound healing, (2) C31G might be an alternative solution prescribed during early postoperative period after non-regenerative periodontal flap surgery.

CLINICAL RELEVANCE

The present study found that active agent C31G displayed no significant differences to CHX formulations regarding periodontal wound healing improvement and might be used alternatively after non-regenerative periodontal flap surgery. In addition, an alcohol based 0.12% CHX mouthwash was more effective than an alcohol-free 0.12% CHX and C31G mouthrinse on plaque control in the absence of mechanical oral hygiene.

Oxytalan-positive peripheral ossifying fibromas express runt-related transcription factor 2, bone morphogenetic protein-2, and cementum attachment protein. An immunohistochemical study

BACKGROUND

The peripheral ossifying fibroma (POF) represents one of the most common lesions of the periodontal tissues that may originate from the gingival soft tissues, the periosteum, or the periodontal ligament.

AIM

To investigate the immunohistochemical expression of runt-related transcription factor 2 (Runx-2), bone morphogenetic protein-2 (BMP-2), and cementum attachment protein (CAP) in oxytalan-positive POF, to establish the use of POF as an in vivo model for the study of the periodontal ligament.

MATERIALS AND METHODS

Thirty tumors that presented clinical and histologic features of POF, as well as oxytalan fibers, were included in the study. Immunohistochemical expression of Runx-2, BMP-2, and CAP was evaluated by light microscopy.

RESULTS

Runx-2, BMP-2, and CAP were abundantly expressed by POFs; 22 of 30 tumors expressed positive staining for Runx-2, twenty-six tumors for BMP-2, and twenty-five tumors for CAP. The expression of Runx-2 was abundant in POFs where bone was histologically present (P = 0.04) and of BMP-2 in POFs where dystrophic calcifications were present (P = 0.03).

CONCLUSION

It is suggested that oxytalan-positive POFs, purportedly originating from the periodontal ligament, express molecules that are specific to bone and cementum (Runx-2, BMP-2), or cementum only (CAP). Thus, the cell populations present in the lesion belong to the mineralized-tissue-forming cell lineages, the cementoblastic or osteoblastic lineage.

Association between periodontitis and acute myocardial infarction: a case-control study of a nondiabetic population

BACKGROUND AND OBJECTIVE

Periodontitis and acute myocardial infarction (AMI) are two diseases that share common risk factors. The role of periodontitis as an independent risk factor for cardiovascular disease has been under debate. The aim of this study was to investigate whether an association exists between periodontitis and AMI in a nondiabetic population, using multiple periodontal case definitions.

MATERIAL AND METHODS

Periodontal examination was performed in 204 patients with AMI. The control group comprised 102 healthy subjects, without significant coronary disease, confirmed angiographically. Periodontitis was assessed using measurements of clinical attachment loss (CAL), probing depth and number of missing teeth. From these measurements, five different case definitions of periodontitis were generated.

RESULTS

Using the continuous forms of periodontal measurements, the odds ratio (95% confidence interval) of the association with incident AMI was 1.74 (1.26-2.50), 1.83 (1.10-3.17) and 1.08 (1.06-1.13) for mean CAL, probing depth and number of missing teeth, respectively. A consistent positive association was observed regardless of the case definition of periodontitis.

CONCLUSION

In this nondiabetic population, the association between periodontitis and AMI was consistent across different measurements and/or definitions of periodontitis. The strength of the association increased concomitantly with the robustness of the criteria used to define periodontitis.

Dental terms in Julius Pollux's the Onomasticon

Julius Pollux's The Onomasticon, a lexicographical work, contains a large number of terms on dental and oral issues; through them, we can see people's perceptions about the dental arches and the oral cavity in the 2nd century CE. The dental arches are presented thoroughly, naming the groups of teeth and presenting their characteristics. Special mention is made of the wisdom teeth. Pollux also gives a brief description of the tooth in general, the alveolar process and the gingiva. He also refers to dental anomalies and diseases.

Effect of non-surgical periodontal therapy on C-reactive protein, oxidative stress, and matrix metalloproteinase (MMP)-9 and MMP-2 levels in patients with type 2 diabetes: a randomized controlled study

BACKGROUND

It is well accepted that glycemic control in patients with diabetes mellitus (DM) is affected by systemic inflammation and oxidative stress. The effect of periodontal therapy on these systemic factors may be related to improvement on glycemic status. The aim of the present study is to assess over a period of 6 months the effect of non-surgical periodontal therapy on serum levels of high-sensitivity C-reactive protein (hsCRP), d-8-iso prostaglandin F2a (d-8-iso) as a marker of oxidative stress, and matrix metalloproteinase (MMP)-2 and MMP-9 on patients with type 2 DM.

METHODS

Sixty participants with type 2 DM and moderate to severe periodontal disease were randomized into intervention (IG) and control (CG) groups. IG received scaling and root planing, whereas CG received supragingival cleaning at baseline and scaling and root planing at 6 months. Participants of both groups were evaluated at baseline and 1, 3, and 6 months. Periodontal data recorded at each visit included probing depth, clinical attachment loss, bleeding on probing, and gingival index. Blood was collected at each visit for the assay of serum glycated hemoglobin A1c (A1c), hsCRP, d-8-iso, MMP-2, and MMP-9.

RESULTS

Although there was a trend to a reduction in hsCRP, d-8-iso and MMP-9 it did not reach statistical significance. MMP-2 levels remained unchanged after periodontal treatment.

CONCLUSION

Effective non-surgical periodontal treatment of participants with type 2 DM and moderate to severe periodontal disease improved significantly A1c levels but did not result in a statistically significant improvement in hsCRP, d-8-iso, MMP-2, and MMP-9 levels.

Attachment and proliferation of human osteoblast-like cells on guided bone regeneration (GBR) membranes in the absence or presence of nicotine: an in vitro study

PURPOSE

To compare in vitro the attachment and proliferation of human osteoblast-like cells (MG63) on tissue culture plates and guided bone regeneration (GBR) membranes in the absence or presence of nicotine.

MATERIALS AND METHODS

Membrane samples were fixed to wells and the cell number (CN) was counted after 24 hours (attachment assay) or 5 days (proliferation assay). The ratio of cell count (RCC) (CN at 5 days/CN at 24 hours) was calculated. The study had three parts: First, five different resorbable GBR membranes were compared (Resolut Adapt LT [RALT], Biocollagen [BC], Bio-Gide [BG], OsseoGuard [OG], and Demokritos Human Tissue Bank [DEM]). Next, cells were cultured on tissue culture plates with five different concentrations of nicotine. Finally, cells were cultured on the membrane that had demonstrated the highest RCC and CN in part 1 with four different concentrations of nicotine.

RESULTS

At 24 hours, BG showed the highest CN and OG showed the lowest CN. At 5 days, BG showed the highest CN. The order of RCC was BG > OG > DEM > RALT ~ BC. At 24 hours, lower nicotine concentrations (0.3 and 3 μg/mL) showed higher CNs versus the control, whereas CNs for high nicotine concentrations (30 and 300 μg/mL) were lower than for the control. CN at 5 days and RCC were lowest with 300 μg/mL nicotine. At 24 hours and 5 days, all differences among wells with membrane were statistically insignificant. Nevertheless, CN at 5 days and RCC were highest with the lowest nicotine concentration (3 μg/mL) and lowest with high concentrations.

CONCLUSIONS

Membrane materials influence attachment and proliferation of bone cells and, therefore, could affect the outcomes of GBR. On both tissue culture plates and membranes, there is a tendency toward a biphasic effect of nicotine, with stimulatory effects at low concentrations and inhibitory effects at high concentrations.

Effect of rhTGF-β1 combined with bone grafts on human periodontal cell differentiation

Various techniques and materials have been proposed for the treatment of periodontal defects. In periodontal regeneration, periodontal ligament (PDL) cell differentiation as well as certain growth factors and their delivery system applied are critical. The purpose of this study was to evaluate the in vitro effect of recombinant human transforming growth factor-beta 1 (rhTGF-β1) combined with two different bone grafts on human PDL (hPDL) cell differentiation. The hPDL cells were treated with TGF-β1 alone or in combination with a calcified freeze-dried bone allograft (FDBA) and a porous biphasic calcium phosphate (BC) bone graft. Cell differentiation effect was estimated by measuring alkaline phosphatase (ALPase) activity and osteocalcin secretion. Results demonstrated that rhTGF-β1 alone or in combination with FDBA and BC provoked a significant (p<0.05) increase in ALPase activity as compared with controls. The findings of this study confirmed the beneficial role of rhTGF-β1 combined with FDBA and BC as carriers in periodontal regeneration.

A randomized, controlled trial on the effect of non-surgical periodontal therapy in patients with type 2 diabetes. Part I: effect on periodontal status and glycaemic control

AIM

the purpose of the present study was to assess the effect of non-surgical periodontal therapy on glycaemic control of type 2 diabetes patients with moderate-to-severe periodontitis.

MATERIALS AND METHODS

this was a randomized, controlled clinical trial of patients with type 2 diabetes. A total of 60 patients with moderate-to-severe periodontal disease were assigned to either a periodontal treatment arm, consisting of scaling and root planing (intervention group [IG]), or a delayed treatment arm that received periodontal care after 6 months (control group [CG]). Periodontal parameters and glycosylated haemoglobin (A1C) were evaluated at 1, 3 and 6 months.

RESULTS

all periodontal parameters improved significantly in the IG. A1C levels decreased statistically significantly more in the IG versus the CG (0.72%versus 0.13%; p<0.01) independently of other confounders.

CONCLUSIONS

this study provides evidence that periodontal treatment contributes to improved glycaemic control in type 2 diabetes mellitus patients. Larger controlled trials are needed to confirm if this finding is generalizable to other populations of patients with type 2 diabetes.

Effect of rhBMP-7 combined with two bone grafts on human periodontal ligament cell differentiation

The purpose of this study was to evaluate the in vitro effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) combined with demineralised freeze-dried bone allograft (DFDBA) and an inorganic bovine material with a synthetic peptide (PepGen P-15) on human periodontal ligament (hPDL) cell differentiation, in a time-dependent manner. hPDL cells were cultured and treated with: (1) 500 ng/ml of rhBMP-7, (2) 10 mg of DFDBA or PepGen P-15 and (3) their combination. Cell differentiation was estimated after 48 and 72 h by measuring alkaline phosphatase (ALPase) activity and osteocalcin (OC) secretion. The presence of rhBMP-7, DFDBA, PepGen P-15, rhBMP-7 + DFDBA and rhBMP-7+ PepGen P-15 promoted a significant increase of ALPase activity after 48 and 72 h. The combination of rhBMP-7 with DFDBA or PepGen P-15 did not lead to significant OC secretion. The results of this study imply that rhBMP-7 stimulates the early osteoblastic differentiation of hPDL cells and that DFDBA and PepGen P-15 could serve as carriers for rhBMP-7.

Effect of homologous PRP on proliferation of human periodontally affected osteoblasts. In vitro preliminary study. Report of a case

OBJECTIVE

The purpose of this in vitro study was to evaluate the effect of two concentrations of homologous platelet-rich plasma (PRP) on the proliferative response of osteoblasts derived from a patient with aggressive periodontitis.

METHODS

8.5 ml of venous blood were taken from 1 healthy and non-smoker volunteer. PRP was prepared following the protocol of Curasan. Osteoblasts were derived from alveolar bone chips obtained from a patient with aggressive periodontitis during conventional periodontal surgery and a clinically healthy person during crown lengthening surgical procedure. Cells were grown in 24-well dishes and on day 2 of quiescence were treated with 1% and 5% (v/v) of PRP. The effect on cell proliferation was estimated by measuring [3H] thymidine incorporation. After 48h of incubation, cells were processed to subject to scintillation counting. Counts per minute were determined for each sample.

RESULTS

The addition of 1% and 5% of PRP provoked a statistical significant (p<0.05) increase in cell growth.

CONCLUSIONS

Data revealed significant enhancement of proliferative response of osteoblasts in the presence of PRP, which might serve as a source of growth factors promoting periodontal repair by modulating cell response and activities.

Platelet-rich plasma effect on periodontally affected human gingival fibroblasts: an in vitro study

OBJECTIVE

The purpose of this study was to evaluate the gingival fibroblast proliferative response derived from patients with chronic and aggressive periodontitis to homologous platelet-rich plasma (PRP).

MATERIALS AND METHODS

Gingival fibroblasts derived from nine patients with chronic periodontitis, aggressive periodontitis and healthy periodontium were grown. Medium was replaced with DMEM containing 0.5% FBS in which cells remained for two days. Cells were incubated and cultured with medium containing 50 microl/ml homologous platelet-rich plasma (PRP) or not containing PRP (control) for 24 and 48 hours. PRP originated from three donors. Cell proliferation effect was evaluated at 24 and 48 hours. Cell viability was assessed with a hemocytometer. Viable cells were counted under a phase contrast microscope.

RESULTS

The results revealed that incubation of human gingival fibroblasts, derived from healthy and intact periodontium, chronic periodontitis and aggressive periodontitis, in culture medium containing homologous PRP statistically significantly increased the cell proliferation at 24 and 48 hours of culture.

CONCLUSION

The addition of PRP to human gingival fibroblast cultures significantly increased the proliferative response, irrespective of the presence of periodontitis, type of periodontitis and PRP donor.

Periodontitis Associated With Hajdu-Cheney Syndrome

BACKGROUND

Hajdu-Cheney syndrome (HCS) is an inheritable, rare disorder of bone metabolism, associated with acro-osteolysis of the distal phalanges, short stature, distinctive craniofacial and skull changes, premature tooth loss, and periodontitis. This report focuses on the periodontal manifestations of HCS.

METHODS

A 22-year-old female presented with the characteristic clinical features of HCS, including short stature, small face, prominent epicanthal folds, thin lips, small mouth, and short hands. There were no abnormal biochemical, hematological, or hormonal data. Tests for bone mineral density were indicative of osteoporosis. Cephalometric analysis revealed hypoplasia of the midface and increased cranial base angle; the maxilla and the mandible were set posteriorly. The sella turcica was enlarged, elongated, and wide open with slender clinoids. Hair samples were examined by scanning electron microscopy, and tooth cementum and dentin were evaluated histologically.

RESULTS

According to the periodontal evaluation, gingival inflammation was 12.5%, bleeding on probing score was 24%, probing depths averaged 4 to 6 mm, and clinical attachment loss averaged 3 to 6 mm. Class II furcations were found on three teeth. Almost all teeth exhibited pathological mobility of varying degrees. There was a generalized, horizontal bone loss of approximately 50%. Three teeth had to be extracted because of severe localized periodontal destruction. Histologic examination of the dentin and the cementum was normal.

CONCLUSIONS

HCS periodontitis is associated with an unpredictable and uneven, rapid rate of periodontal destruction of unknown etiology. Further research is required to identify the role of the possible pathogenic factors involved.

Contamination of a toothbrush with antibacterial properties by oral microorganisms

OBJECTIVES

The aim of this study was to examine the contamination and the survival rate of periodontopathic and cariogenic species on new toothbrushes with antibacterial properties (coated bristles with triclosan), after a single use in periodontitis patients. The decontamination effect of the use of toothpaste was also evaluated.

METHODS

Ten patients, who consulted the Department of Periodontology, for treatment of chronic periodontitis, were selected. In each patient four different toothbrushes were used. Two quadrants, randomly selected, were each brushed using a different antibacterial toothbrush. In one of these two quadrants toothpaste was used. The same happened with the remaining quadrants, only with regular toothbrushes. After brushing, the toothbrushes were rinsed and stored in room temperature and a dry environment. After 0, 4 and 24h, four tufts, from each toothbrush, were cut and processed for selective and non-selective culturing techniques, followed by identification and quantification of all species found.

RESULTS

Immediately after brushing the toothbrushes harbored a significant number of microorganisms, with no statistically significant difference between the two types of brushes (regular and antibacterial). The reduction of microorganisms from 0 to 4h after brushing was statistically significant (p<0.05). The difference was less obvious from 4 to 24h. When toothpaste was used, brushes harbored significantly (p<0.05) lower numbers of colony-forming units (CFU) compared to those without the use of toothpaste.

CONCLUSIONS

The antibacterial toothbrush with triclosan coated tufts failed to limit the bacterial contamination. The toothpaste, on the other hand, significantly reduced the contamination of toothbrushes.

Role of growth factors on periodontal repair

Regeneration of periodontal structures lost during periodontal diseases constitutes a complex biological process regulated among others by interactions between cells and growth factors. Growth factors are biologically active polypeptides affecting the proliferation, chemotaxis and differentiation of cells from epithelium, bone and connective tissue. They express their action by binding to specific cell-surface receptors present on various target cells including osteoblasts, cementoblasts and periodontal ligament fibroblasts. The observation that growth factors participate in all cell functions led to exogenous application during periodontal tissue repair aiming to their use as an alternative therapeutic approach to periodontal therapy. Cell types and cultures conditions, dose, carrier materials, application requirements are of critical importance in the outcome of periodontal repair. The purpose of this article is to review the literature with respect to the biological actions of PDGF, TGF, FGF, IGF and EGF on periodontal cells and tissues, which are involved in periodontal regeneration.

Time- and dose-dependent mitogenic effect of basic fibroblast growth factor combined with different bone graft materials: an in vitro study

OBJECTIVES

In periodontal regeneration, the growth factor concentrations and the delivery system used are of great importance. In an attempt to assess the mitogenic effect of basic fibroblast growth factor (bFGF) on periodontal ligament (PDL) cells combined with different bone replacement materials, two allografts of cortical (DFDBA) and cancellous (DFBA) bone and an anorganic bovine material with a synthetic peptide (ABM P-15) were used. The purpose of this study was to evaluate the in vitro mitogenic effect of different doses of bFGF alone or in combination with DFDBA, DFBA and ABM P-15 on human PDL cells in a time-dependent mode.

MATERIAL AND METHODS

PDL cell cultures were derived from the mid-root of four maxillary premolars. Cells were grown and reached confluence. On day 2 of quiescence, new medium was added along with (1) 1, 5, 10 and 25 ng/ml of bFGF alone, (2) 10 mg of DFDBA, DFBA and ABM P-15 alone and (3) their combination. The mitogenic effect was determined at 24 and 48 h of culture by using a hemocytometer chamber. The cells were counted under a phase contrast microscope.

RESULTS

The results revealed that bFGF at the highest concentrations and after 48 h exerted a significant mitogenic effect on PDL cells, and also DFDBA and DFBA supported cell proliferation. Furthermore, DFDBA and DFBA enriched with bFGF had a significant mitogenic effect after 48 h of culture. ABM P-15 with 10 and 25 ng/ml of bFGF up-regulated PDL cell proliferation after 48 h of incubation.

CONCLUSIONS

The findings of this study demonstrate the beneficial role of bFGF combined with DFDBA and DFBA as carriers in periodontal repair.

Ability of a bovine bone graft, alone or enriched with PDGF-BB or rhBMP-2, to promote human periodontal ligament (PDL) cells proliferation. A preliminary study

One of the most important goals of the periodontal therapy procedures is to stimulate the formation of new bone into osseous defects resulted from periodontal disease. A wide range of grafting materials is used to achieve this aim. Recently, the Human Tissue Bank of the National Center for Scientific Research 'Demokritos' in Athens (Greece) has prepared, in a preliminary study, a cancellous bovine-derived bone matrix (BBM). The purpose of the present work was to investigate the role of this bovine bone material in the periodontal regeneration, by studying the rate of human periodontal ligament (PDL) cells proliferation in the presence of this matrix alone, or after the addition of the growth factors, platelet-derived growth factor-BB (PDGF-BB) or recombinant human bone morphogenetic protein-2 (rhBMP-2).Bovine bone graft was prepared using the 'know how' acquired by the 30 years continuous preparation and delivery of lyophilized human bone grafts by the 'Demokritos' Bank.PDL cells cultures were derived from the mid root of two maxillary premolars. The teeth were caries-free and were extracted for orthodontic reasons from 1 adult female patient. Cells were grown in 24-well dishes in the presence of 20 mg BBM. On day 2 of quiescence, new medium was added with 10 ng/ml of PDGF-BB or 50 ng/ml of rhBMP-2. To determine the effects of the test agents on cell proliferation, DNA synthesis was estimated by measuring [(3)H] thymidine incorporation. After 48 h of incubation the cells were processed to subject to scintillation counting. Counts per minute (cpm/well) were determined for each sample.The results revealed that this BBM has the ability to maintain PDL cells proliferation and could be used as an alternative graft material. PDGF-BB when added improved the cell proliferative response resulting in a more active BBM, while the presence of rhBMP-2 did not support cell mitosis.

Human periodontal ligament cell responses to recombinant human bone morphogenetic protein-2 with and without bone allografts

BACKGROUND

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been found to promote the osteoblastic differentiation of human periodontal ligament cells. Its effect depends on the delivery system used. In this study we examined the effect of rhBMP-2 on the proliferation and osteoblastic differentiation of human periodontal ligament cells cultured alone or with 3 different bone allografts.

METHODS

The rhBMP-2 effect on cell proliferation and osteoblastic differentiation was examined by measuring [3H] thymidine incorporation and ALPase activity, respectively, on human periodontal ligament (hPDL) cells. Two human demineralized freeze-dried allografts of cortical (DFDBAco) and cancellous (DFBDAca) bone origin and 1 non-demineralized freeze-dried allograft (FDBA) of cancellous bone origin, derived from different tissue banks, were used to evaluate the rhBMP-2 effect on cell osteoblastic differentiation. The measurements were taken on various days.

RESULTS

rhBMP-2 decreased hPDL cell proliferation. rhBMP-2 acted on the third day of the process of cell differentiation, had a specific time of action, achieved its peak effect on the fourth and fifth days, and then did not provoke any further effects. The 3 bone allografts were efficiently combined with rhBMP-2. The combination of rhBMP-2 and DFDBAco showed the effect with the longest duration. rhBMP-2, on day 4, made the inactive bone allograft more active while, on the other days, its effect was dependent on the allograft alone.

CONCLUSIONS

rhBMP-2 promotes the osteoblastic differentiation of human periodontal ligament cells and decreases cell proliferation. In this study rhBMP-2 in the presence of the bone allografts tested resulted in hPDL cell differentiation.

Proliferative effect of growth factors TGF-beta1, PDGF-BB and rhBMP-2 on human gingival fibroblasts and periodontal ligament cells

The regeneration of periodontal tissues lost due to periodontal disease requires cell migration, differentiation and proliferation. Several procedures have been proposed to promote wound healing events such as the application of growth factors including PDGF-BB, TGF-beta1 and rhBMP-2. The purpose of this study was to evaluate the mitogenic responses of human periodontal ligament cells and gingival fibroblasts to PDGF-BB, TGF-beta1 and rhBMP-2. Human periodontal ligament cells were isolated from the mid root of three maxillary third molars extracted from three adult patients with moderate periodontitis and gingival fibroblasts were obtained from two patients also affected by moderate periodontitis, who underwent periodontal surgery. Cells were grown in 24-well dishes. On day 2 of quiescence, new medium was added with PDGF-BB or TGF-beta1 or rhBMP-2 at the concentration of 10 ng/ml. To determine the effects of the test agents on cell proliferation, DNA synthesis was estimated by measuring [3H] thymidine incorporation. After 48h of incubation the cells were processed and subject to scintillation counting. Counts per minute (cpm/ well) were determined for each sample. The results of this study demonstrated that PDGF-BB acts like a strong mitogenic agent for human periodontal ligament cells and gingival fibroblasts, TGF-beta1 mostly supports the proliferation of these cells and rhBMP-2 had an opposite effect on cell mitosis.

In vitro evaluation of the mitogenic effect of platelet-derived growth factor-BB on human periodontal ligament cells cultured with various bone allografts

BACKGROUND

Several studies have documented the role of growth factors in periodontal regeneration. It has been shown that platelet-derived growth factor (PDGF) is a potent stimulator of human periodontal ligament (PDL) cells. A variety of bone graft materials are used to treat osseous defects caused by periodontal disease. We evaluated the mitogenic effect of PDGF on human PDL cells cultured with different allografts to determine which of the allografts with or without PDGF promoted periodontal regeneration.

METHODS

Two human demineralized freeze-dried allografts of cortical (DFDBA) and cancellous (DFBA) bone and a non-demineralized freeze-dried allograft (FBA) from cancellous bone were used alone or supplemented with PDGF-BB. Human PDL cultures were derived from the mid-root of 2 maxillary premolars extracted for orthodontic reasons. Cells were grown separately in 24-well dishes with or without 20 mg of each bone allograft. On day 2 of quiescence, new medium was added with 10 ng/ml of PDGF-BB. DNA synthesis was estimated by measuring [3H] thymidine incorporation to determine the effects of the test agents on cell proliferation. Cells were processed and subjected to scintillation counting after 48 hours of incubation. Counts per minute (cpm/well) were determined for each sample.

RESULTS

There was no statistically significant difference (P<0.05) on PDL cell proliferation when the allografts were used alone. PDL cells exhibited significantly greater proliferative responses to the 2 demineralized bone allografts, DFDBA and DFBA, when combined with PDGF-BB. A statistically significant difference on DNA synthesis was noticed when PDGF-BB was added to PDL cells cultured with FBA. PDL cells displayed no significant increase in mitogenic activity when cultured with PDGF-BB alone.

CONCLUSIONS

The findings of this study demonstrate the beneficial role of DFDBA, DFBA, and FBA as synergic agents with PDGF-BB to periodontal regeneration. The significant ability of the 2 decalcified bone allografts, DFDBA and DFBA, combined with PDGF to stimulate PDL cell proliferation might be a useful adjunct in the treatment of periodontal defects.

[Pain. Evaluation of the developing pain theories. The psychological factor]

In this paper we presented the different theories and opinions regarding the development of pain. After a very brief historical review including the ideas of Homer, Hippocrates, Aristoteles, St. Thomas Aquinas, we reviewed the 19th century's theories including Whytt, Brodie, Inman and Austie. From the modern period we emphasized the "gate theory" introduced originally by Melzack and Well. The psychological aspects has been also examined and the patient as "a dental patient" also described.