Systemic Doxycycline Research Articles

Effect of scaling and root planing combined with systemic doxycycline therapy on glycemic control in diabetes mellitus subjects with chronic generalized periodontitis: a clinical study.

PurposeThe purpose of study was to compare glycemic control using glycated hemoglobin levels (HbA1c) in diabetic patients with chronic generalized periodontitis (CGP) undergoing scaling and root planing (SRP) with and without systemic doxycycline.MethodsFifty subjects with type 2 diabetes mellitus (T2DM) and CGP receiving antidiabetic therapy were selected for study. The selected subjects were randomly assigned to two groups (test group [TG] and control group [CG]) comprising 25 patients each. The TG received SRP followed by systemic doxycycline. The CG received treatment with SRP only. The periodontal parameters were recorded at baseline (day zero), and every 1 month for 4 months and included probing depth, clinical attachment level, plaque index, gingival index, and HbA1c level were recorded at baseline (day zero) and at the end of 4 months.ResultsA statistically significant effect was demonstrated for the periodontal parameters for both the TG and CG. HbA1c values did not show a statistically significant difference in the treatment group as compared to the CG.ConclusionsThe authors concluded that nonsurgical periodontal therapy improved glycemic control in patients with T2DM in both groups, but no statistical difference was observed with adjunctive systemic doxycycline therapy. A further study with a larger sample size is required.

Direct detection of Ehrlichia canis by PCR in the conjunctiva of a dog with bilateral anterior uveitis

The following report describes the direct detection of Ehrlichia canis by real-time PCR in the conjunctiva of a 1-year-old female Maltese dog. After being imported from Brazil, the dog was presented because of anorexia, dehydration, fever, and palpable mandibular lymph nodes. A few days later, the dog developed bilateral blepharospasm, photophobia and anterior uveitis. Monocytic ehrlichia was diagnosed by a positive PCR result and the detection of IgM and IgG antibodies. Because of the massive uveitis a conjunctival sample was taken with a cytobrush, which also tested positive for Ehrlichia canis DNA by real-time PCR. Only one week after starting treatment with systemic doxycycline and local anti-inflammatory and cyclopalgic therapy the dog recovered from systemic and eye diseases. After therapy the follow-up examination revealed a full remission of clinical and hematological parameters and negative PCR result.

Regenerative therapy of infrabony defects with or without systemic doxycycline. A randomized placebo‐controlled trial

Comparison of regenerative therapy of infrabony defects with and without administration of postsurgical systemic doxycycline (DOXY). In each of 61 patients one infrabony defect was treated with enamel matrix derivative (EMD), EMD plus filler or membrane at two centres. By random assignment patients received either 200 mg DOXY per day or placebo (PLAC) for 7 days after surgery. Prior to and 6 months after surgery probing pocket depths (PPD) and vertical attachment level (PAL-V) were obtained. Fifty-four patients (DOXY: 27; PLAC: 27) were re-examined after 6 months and had been treated exclusively with EMD. Seven to 8 days after surgery 81% of defects in both groups showed complete flap closure. In both groups significant (p < 0.001) PPD reduction (DOXY: 3.87 ± 1.44 mm; PLAC: 3.67 ± 1.30 mm) and PAL-V gain (DOXY: 3.11 ± 1.50 mm; PLAC: 3.32 ± 1.83 mm) were observed. However, the differences failed to be statistically significant (PPD: 0.20; p = 0.588; PAL-V: 0.21; p = 0.657). Two hundred milligram systemic DOXY administered for 7 days after therapy of infrabony defects with EMD failed to result in better PPD reduction and PAL-V gain compared with PLAC which may be due to low power (50%) and, thus, random chance.

Percutaneous sclerotherapy in neonatal and infant head and neck lymphatic malformations: a single center experience

Purpose To evaluate the clinical outcomes of percutaneous sclerotherapy for congenital head and neck lymphatic malformations in our institution. Materials and Methods Over a 7-year period, 17 children (10 M, 7 F) mean age 5.8 months (5 days to 13 months) underwent 49 sclerotherapy procedures for congenital head and neck malformations. The imaging and clinical records were reviewed for each patient. Ten of 17 had macrocystic disease; 7 of 17 had microcystic disease. Imaging response was categorized by volume reductions of 0% to 25%, 25% to 50%, 50% to 75%, or 75% to 100%. A concentration of 10 mg/mL doxycycline was used routinely via catheter in 3 instillations with a dose range of 50 to 500 mg per session as per our standard protocol in 17 of 17 patients. In more recent patients, systemic doxycycline levels were obtained after instillations. Additional treatments included direct injection doxycycline (10/17), instillation of absolute ethanol (7/17) or sodium tetradecyl sulfate (4/17), or a combination of these methods. Results Imaging improvement of ≥76% was noted in 11 of 17. Of these, 8 of 11 had macrocystic disease. Four of 17 had 51% to 75% resolution, of which 3/4 were mixed. Two of 17 children had 25% to 50% resolution with a mixed lesion. Seven of 49 peri-procedural complications: hemolytic anemia in 2 infants, hypoglycemic and metabolic acidosis in 3 neonates aged 7 to 10 days, transient hypotension during absolute alcohol instillation in 1 neonate, and self-limiting skin excoriation secondary to peri-catheter leakage of doxycycline in one neonate. Neonates prone to these systemic complications had doxycycline doses of greater than 250 mg and resulted in serum levels of >5 μg/mL but as high as 21 μg/mL. Delayed neural complications occurred in 7 of 49 procedures, Horner's syndromes in 4 of 49 procedures, transient left lip weakness in 1 of 49 procedures, right facial nerve palsy in 1 of 49 procedures, and transient left hemidiaphragm paralysis in 1/49 procedures. Conclusion Our experience with catheter directed doxycycline sclerotherapy provides excellent results for large macrocystic head and neck lymphatic malformations. Microcystic and mixed lesions continue to provide a therapeutic challenge.

A Case Report of Doxycycline-induced Stevens–Johnson Syndrome

To report the clinical findings of a case of Stevens-Johnson syndrome (SJS) precipitated by the use of systemic doxycycline. Case report. A 49-year-old man developed SJS with ocular involvement after doxycycline use for respiratory symptoms. The patient developed persistent 2+ conjunctival injection and foreshortening of the conjunctival fornices in both eyes. The right eye had a 3 × 3.4 mm corneal epithelial defect with 50% thinning. The left eye had a 2.6 × 3 mm corneal ulcer with a central perforation and a flat anterior chamber with 360 degrees of iridocorneal touch. This case illustrates the unusual presentation of SJS induced by doxycycline. The prevalent use of systemic doxycycline in the practice of ophthalmology for eyelid-related and ocular surface disorders coupled with the detrimental long-term sequelae of SJS renders a careful reevaluation for alternatives.

Poststreptococcal keratouveitis associated with group C streptococcus pharyngitis

PurposeTo report the first case of poststreptococcal syndrome uveitis (PSU) in association with group C streptococcus (GCS).Patients and methodsChart review of a 24-year-old man who presented with bilateral ocular redness, pain, and photophobia for 5 days and “white rings” around his eyes for a duration of 3 days. The patient further reported fever and sore throat in the preceding week. Slit-lamp examination showed bilateral keratouveitis. A thorough uveitis workup, antistreptolysin O (ASLO) titer, and throat culture were obtained. The patient was treated with frequent topical steroids and systemic doxycycline. The uveitis and keratitis subsided over the next few weeks, leaving extensive peripheral keratolysis.ResultsThe results of laboratory diagnostic testing revealed an elevated ASLO, C-reactive protein, as well as HLA-B27 positivity. Throat cultures grew beta-hemolytic GCS; group A streptococcus was culture negative.ConclusionGCS pharyngitis may be a causative organism of PSU.

Short‐Term Effects of Photodynamic Therapy on Periodontal Status and Glycemic Control of Patients With Diabetes

Periodontitis is a major cause of tooth loss among adults. Several studies have shown a possible systemic impact of periodontal infection, including poor glycemic control in patients with diabetes. Recently, photodynamic therapy (PDT) was used to successfully treat periodontal infection. PDT provides a broad spectrum antimicrobial efficacy with no local or systemic side effects. The objective of this study was to examine the effect of the adjunctive use of PDT on periodontal status and glycemic control of patients with diabetes and periodontitis. Forty-five patients with type 2 diabetes and moderate to severe chronic periodontitis were selected and randomly assigned to one of the following three treatment modalities (15 subjects each): scaling and root planing (SRP) only, SRP plus systemic doxycycline, and SRP plus PDT. The plaque and bleeding scores, probing depth, clinical attachment level, and glycosylated hemoglobin (HbA1c) level were recorded at baseline and 3 months after periodontal treatment. Descriptive statistics, the paired t test, and analysis of variance (ANOVA) were used for data analysis. Statistically significant differences in the mean probing depth, clinical attachment level, plaque deposit, and bleeding on probing were found between baseline and 12 weeks post-treatment for all groups. No significant differences in periodontal parameters and glucose levels were detected among the three groups. Reduction in the mean HbA1c level after treatment was observed in all groups but was only significant for the SRP plus doxycycline group. The results of the present study indicate that PDT does not benefit conventional non-surgical periodontal therapy in patients with diabetes.

Effects of Periodontal Therapy on Glycemic Control and Inflammatory Markers

Periodontitis, a complication of diabetes mellitus (DM), can induce or perpetuate systemic conditions. This double-masked, placebo-controlled study evaluated the effects of periodontal therapy (scaling and root planing [SRP]) on the serum levels of glycated hemoglobin (HbA1c) and on inflammatory biomarkers. Thirty subjects with type 2 DM and periodontitis were treated with SRP + placebo (SRP; N = 15) or with SRP + doxycycline (SRP+Doxy; N = 15), 100 mg/day, for 14 days. Clinical and laboratory data were recorded at baseline and at 3 months after treatment. After 3 months, the reduction in probing depth was 0.8 mm for the SRP group (P <0.01) and 1.1 mm for the SRP+Doxy group (P <0.01) followed by a 0.9% (SRP; P = 0.17) and 1.5% (SRP+Doxy; P <0.01) reduction in HbA1c levels. A significant reduction in interleukin (IL)-6; interferon-inducible protein 10; soluble fas ligand; granulocyte colony-stimulating factor; RANTES; and IL-12 p70 serum levels were also verified (N = 30). To our knowledge, this is the first report on the effects of periodontal therapy on multiple systemic inflammatory markers in DM. Periodontal therapy may influence the systemic conditions of patients with type 2 DM, but no statistical difference was observed with the adjunctive systemic doxycycline therapy. Moreover, it is possible that the observed improvement in glycemic control and in the reduction of inflammatory markers could also be due to diet, which was not controlled in our study. Therefore, a confirmatory study with a larger sample size and controlled diet is necessary.

The effect of periodontal therapy on the improvement of glycemic control in patients with type 2 diabetes mellitus: A randomized controlled clinical trial

AIMS:The purpose of this study is to investigate the effect of improved periodontal health on glycemic control in type 2 diabetes mellitus (type 2 DM) patients who have generalized periodontitis.MATERIALS AND METHODS:A total of 45 type 2 DM patients with generalized periodontitis were selected for the study. The selected patients were randomly assigned to three groups (groups A, B, and C) comprising 15 patients each: • Group A received treatment with scaling and root planing only. • Group B received treatment with scaling and root planing followed by systemic doxycycline. • Group C received no treatment (control group). The periodontal parameters recorded included plaque index, gingival index, probing pocket depth, and clinical attachment level. These parameters were recorded at baseline (day zero), at 1 month, and at the end of 3 months. The following metabolic parameters were recorded: fasting blood glucose (FBG), postprandial blood glucose (PPBG), and glycated hemoglobin. These were recorded at baseline (day zero) and at the end of 3 months.STATISTICAL ANALYSIS:All the parameters were subjected to repeated-measures ANOVA and Scheffe's post hoc test.RESULTS:A statistically significant effect could be demonstrated for periodontal parameters for both group A and group B (treatment groups). Glycated hemoglobin values showed statistically significant decrease in treatment groups compared to the control group, with group B showing more significant decrease than group A.CONCLUSIONS:The results of this study showed that nonsurgical periodontal treatment is associated with improved glycemic control in type 2 DM patients.

Demonstration of in vivo transfer of doxycycline resistance mediated by a novel transposon

The aim of this study was to investigate the transfer of bacterial doxycycline resistance between oral bacteria in subjects receiving systemic doxycycline for the treatment of periodontitis. Streptococci were cultured before and after treatment from the subgingival plaque of two patients with periodontitis, genotyped and investigated for the presence of antimicrobial resistance determinants and conjugative transposons. In one subject, a strain of Streptococcus sanguinis resistant to doxycycline was a minor component of the pre-treatment streptococcal flora but dominated post-treatment. In a second subject, a strain of Streptococcus cristatus, which was sensitive to doxycycline before treatment, was found to have acquired a novel conjugative transposon during treatment, rendering it resistant to doxycycline and erythromycin. The novel transposon, named CTn6002, was sequenced and found to be a complex element derived in part from Tn916, and an unknown element which included the erythromycin resistance gene erm(B). A strain of Streptococcus oralis isolated from this subject pre-treatment was found to harbour CTn6002 and was therefore implicated as the donor. This is the first direct demonstration of transfer of antimicrobial resistance carried on a conjugative transposon between oral bacteria during systemic antimicrobial treatment of periodontitis in humans.

Systemic doxycycline and nonsurgical periodontal treatment in diabetic patients

This was a randomised controlled trial (RCT). Group 1 (30 patients) was given oral-hygiene instruction, scaling and root planing, chlorhexidine rinses twice a day and doxycycline (100 mg/day for 15 days). Group 2 (30 patients) had the same treatment but without doxycycline. Plaque index (PI), probing pocket depth (PPD), clinical attachment levels (CAL) and bleeding on probing (BOP) were recorded. Both groups had a measurable improvement in all periodontal parameters, since PI, BOP, PPD and CAL were reduced. The reduction in PPD of 6 mm and in BOP became statistically significant when doxycycline was used (group 1), however. Although both periodontal treatment regimens are effective in type-1 diabetics, the use of doxycycline as an adjunct provided more significant results when good plaque control was achieved.

Doxycycline-coated sutures improve the suture-holding capacity of the rat Achilles tendon

Background There is evidence of high matrix metalloproteinase (MMP) activity around sutures inserted into tendons. This probably results in tissue breakdown, allowing the suture to cut through the tendon, and thus contributes to repair-site elongation and gap formation. We therefore hypothesized that treatment with the MMP inhibitor doxycycline would improve the sutureholding capacity of tendon.Animals, methods and results In the first sub-study, rats received a suture in the Achilles tendon. One group was treated with systemic doxycycline and the other received no treatment. At 3, 5, and 7 days, suture-holding capacity was measured mechanically. The pull-out force and energy were reduced in all tendons, at 3 days compared to freshly inserted sutures, but no further reduction was detected at later time points. Doxycycline- treated tendons showed improved suture-holding capacity as measured by higher energy uptake than in untreated tendons. Force at failure showed a trend towards improvement. The effect was most evident on day 3. In the second sub-study, sutures were coated with doxycycline. At 3 days, local doxycycline treatment caused improved suture-holding capacity—as measured by higher force at failure and higher energy uptake.Interpretation We provide proof of a novel treatment principle. MMP inhibitor-coated sutures improve suture-holding capacity during early repair of collagenous tissues.

Pediatric Ocular Acne Rosacea: Long-Term Treatment With Systemic Antibiotics

To report our experience with four cases of pediatric ocular acne rosacea, including responses to long-term systemic treatment. Retrospective interventional case series. The medical records of four consecutive cases diagnosed with pediatric ocular acne rosacea over a period of 36 months were reviewed. Diagnostic criteria were meibomian gland dysfunction, blepharitis, lid margin telangiectasia, punctate superficial keratopathy, and conjunctival hyperemia with or without inferior corneal vascularization. The patients, aged between four and 12, were all females with bilateral disease. Meibomitis, blepharitis, conjunctival hyperemia, and punctuate epitheliopathy was evident in each case. Cutaneous involvement was seen in two cases (50%), and limbal vascularization with subepithelial or stromal infiltrates was present in three cases (75%). One case showed corneal ulceration at presentation. All four children received systemic doxycycline or erythromycin for at least 12 months and showed considerable improvement within the first month of therapy. No recurrence was noted within the mean 25.5 months of follow-up. None of the girls experienced any side effects during the long treatment duration. Ophthalmologists should consider acne rosacea as a potential diagnosis for any child who has any combination of meibomian disease, chronic blepharitis, recurrent chalazia, and chronic symptoms of photophobia, ocular irritation, and redness that does not respond to routine medical treatment. Such patients respond very well to long-term treatment with systemic erythromycin/doxycycline.

Matrix Metalloproteinase Inhibition Attenuates Aortic Calcification

Arterial calcification has been associated with matrix metalloproteinase (MMP)-mediated elastin degradation. In this study, we investigated whether inhibiting MMP activity could reduce calcium accumulation in rodent models of aortic calcification. Aortic calcification was first induced in male Sprague-Dawley rats by administration of vitamin D3. Treatment with doxycycline decreased aortic calcium and phosphorus accumulation, and it reduced aortic gelatinase levels; however, it also prevented the bone resorption associated with high doses of vitamin D3. Using an in vivo model of localized aortic calcification, systemic doxycycline treatment reduced aortic calcium accumulation without affecting serum calcium levels, suggesting a more specific effect of doxycycline in the arterial wall. In organ culture, doxycycline limited aortic calcification caused by exposure to alkaline phosphatase and inorganic phosphate. When GM6001, a synthetic and specific inhibitor of MMPs, was used instead of doxycycline, it had a similar effect. In vivo, periadventitial delivery of GM6001 to calcifying arteries significantly reduced calcification compared with controls. These results suggest that MMPs are involved in aortic calcification, and inhibiting MMP activity could reduce calcium accumulation in the arterial wall.

The effect of periodontal therapy on uncontrolled type 2 diabetes mellitus in older subjects

The purpose of this study was to examine the effect of periodontal therapy on glycemic control in older type 2 diabetic patients. Fifty-two diabetic patients, age 55-80 years (mean age = 61 years), with glycated hemoglobin (HbA1c) 7.5-11.0% (mean +/- s.d. = 8.98 +/- 0.88) and severe periodontitis were included in the present study. The treatment group received mechanical periodontal treatment combined with systemic doxycycline, 100 mg day(-1) for 14 days. The control group received neither periodontal treatment nor systemic doxycycline. Clinical periodontal parameters, fasting plasma glucose (FPG), and HbA1c levels were measures at baseline and 3 months. Periodontal treatment significantly improved periodontal status of the treatment group (P < 0.05), however the reduction in the level of FPG and HbA1c did not reach significance. In the control group, no significant changes in clinical periodontal parameters, FPG and HbA1c levels were observed, except for significant increase in attachment loss (P < 0.05). Comparing the two groups, although the 3-month level of HbA1c of the treatment group was lower than that of the control group, the difference did not reach significance. The results of the present study indicate that the periodontal condition of older Thais with uncontrolled diabetes is: (a) significantly improved 3 months after mechanical periodontal therapy with adjunctive systemic antimicrobial treatment, and (b) rapidly deteriorating without periodontal treatment. The effect of periodontal therapy on the glycemic control of older uncontrolled diabetics will require further studies that will have to include much larger sample sizes.

Orthodontically induced root and alveolar bone resorption: inhibitory effect of systemic doxycycline administration in rats

The aim of the present study was to investigate the effect of systemic administration of low-dose doxycycline (DC) on orthodontic root resorption. The effect on alveolar bone, the cell population involved, and the amount of tooth movement were also evaluated.Fifty-six 40-50-day-old male Wistar rats were used. Six animals served as untreated controls. Six animals were only administered DC for 7 days, by means of a mini-osmotic pump implanted subcutaneously. In 44 animals the maxillary first molar was mesialized by a fixed orthodontic appliance exerting 50 g force upon insertion. In 28 of these animals DC was administered at the time of appliance insertion and throughout the experiment. The animals were sacrificed 7, 10 or 14 days after force application and block sections processed for analysis. An area including the mesial aspect of the distopalatal root and the adjacent inter-radicular alveolar bone was histomorphometrically evaluated. The root resorption area, absolute alveolar bone area, distance between first and second molars, number of odontoclasts, osteoclasts, mononuclear cells on the root, tartrate-resistant acid phosphatase (TRAP)-positive cells on the root, bone, and in the periodontal ligament (PDL) were compared between DC-treated and non-DC-treated animals. The results revealed a significant reduction in root resorption, the number of odontoclasts, osteoclasts, mononuclear cells on the root surface, and TRAP-positive cells on the root and bone for the DC-administered group. The absolute alveolar bone area was greater, whereas the distance between the first and second molars did not differ between groups. In conclusion, systemic administration of low-dose DC in rats may have an inhibitory effect on orthodontically induced resorptive activity.

Bilateral Upper Eyelid Edema in Melkersson-Rosenthal Syndrome

Melkersson-Rosenthal syndrome is an uncommon disorder characterized by a triad of facial nerve palsy, orofacial edema, and fissured tongue. A 42-year-old woman with Melkersson-Rosenthal syndrome presented with painless, nonpitting, bilateral asymmetric upper eyelid edema. The left eyelid was a bit larger than the right eyelid. CT and MRI demonstrated periorbital soft tissue thickening compatible with the microscopic findings of infiltration of lymphocytes, edema, and cystic dilatation of lymphatic vessels. After treatment by systemic doxycycline and corticosteroid, she showed some improvement of the eyelid edema. Isolated bilateral eyelids swelling may be observed in Melkersson-Rosenthal syndrome. In the case of unexplained nonpitting eyelid edema, biopsy should be performed.

Human cytomegalovirus and Epstein‐Barr virus type 1 in periodontal abscesses

Recent studies have linked herpesviruses to severe types of periodontal disease, but no information exists on their relationship to periodontal abscesses. The present study determined the presence of human cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1) in periodontal abscesses and the effect of treatment on the subgingival occurrence of these viruses. Eighteen adults with periodontal abscesses participated in the study. Subgingival samples were collected from each patient with sterile curettes from an abscess-affected site and a healthy control site. HCMV and EBV-1 were identified by polymerase chain reaction at the time of the abscess and at 4 months after surgical and systemic doxycycline therapy. HCMV was detected in 66.7% of periodontal abscess sites and in 5.6% of healthy sites (P=0.002). EBV-1 occurred in 72.2% of abscess sites but not in any healthy site (P<0.001). HCMV and EBV-1 co-infection was identified in 55.6% of the abscess sites. Posttreatment, HCMV and EBV-1 were not found in any study site. HCMV and EBV-1 genomes are commonly found in periodontal abscesses. These data favor a model in which a herpesvirus infection of the periodontium impairs the host defense and serves as a platform for the entrance of bacterial pathogens into gingival tissue with subsequent risk of abscess development.

Histomorphometric evaluation of the effect of doxycycline on the healing of bone defects in experimental diabetes mellitus: A pilot study

Purpose: Bone healing is impaired in diabetes mellitus, particularly due to increased collagen breakdown. Recently, tetracyclines have been used to treat experimental bone defects because they have anticollagenolytic properties, and positive effects on the healing process have been obtained. The objective of this study was to develop a computer-assisted histomorphometric technique to quantitatively determine the amount of regenerating bone within experimental bone defects in a diabetic rodent model. Materials and Methods: This study examined the effects of systemic doxycycline administration on the healing of tibial bone defects in healthy albino rats and in experimentally induced diabetic rats. Twenty-four female albino rats were assigned to 4 groups: diabetic, diabetic plus doxycycline, control, or control plus doxycycline. The standardized bone defects were histomorphometrically examined 10 and 30 days postoperatively. Histomorphometric analysis of the amount of new bone formation was performed using the Zeiss Vision image analysis program KS 400 (Kontron Elektron GmbH, Eching, Germany). Results: At 10 days of healing, the diabetic groups exhibited inferior healing compared with the control groups in terms of the amount of new bone formation within the defects. However, the effect of doxycycline administration to the diabetic and control groups was not statistically different. At 30 days of healing, there were no statistically significant differences between the amount of newly formed bone in any of the groups. Conclusions: This study found that doxycycline administration did not significantly alter the amount of new bone formation during the healing of bone defects in control and diabetic rats. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:898-904, 2002

Radiographic Osseous Regeneration after Initial Therapy with Systemic Doxycycline

Early-onset periodontal diseases are often diagnosed in the military as a result of the requirements for annual dental examinations and the youthful population served. A young soldier diagnosed with rapidly progressive periodontitis completed initial therapy of root planing with the systemic antibiotic doxycycline but was poorly compliant with additional treatment. During a subsequent mandatory dental examination, new radiographs demonstrated a significant improvement in the quantity and quality of alveolar bone, illustrating the regeneration potential of the young patient with early-onset periodontal disease.