bluuebunny/crossref_metadata_2025 huggingface dataset:
Longitudinal Comparisons of the Periodontal Status of Patients with Moderate to Severe Periodontal Disease Receiving No Treatment, Non‐Surgical Treatment, and Surgical Treatment Utilizing Individual Sites for Analysis
Authors: Harrel Stephen K. , Nunn Martha E.
Published: February 2005

Background: The progression of periodontal disease without treatment and the response of existing periodontal disease to various types of treatment have been studied extensively. Many past studies have used the mean of the patient's probing depths or attachment levels to eval‐uate disease progression a s opposed to following changes in individual sites or teeth. The purpose of the current study was to evaluate the response of individual teeth to treatment or non‐treatment.

Methods: The records from a private periodontal practice were reviewed to find patients with complete periodontal examinations that were recorded at least 1 year apart. Patients who fit these criteria were divided into those who had none of the recommended treatment untreated, n = 30); those who had only non‐surgical treatment (par‐tially treated, n = 20); and a control group who had completed all recommended treatment (surgically treated, n = 41). The data for each tooth of each patient were placed in a database and analyzed using the method of generalized estimating equations (GEE) to test for associations between increase or decrease in probing depths and various initial clinical parameters while adjusting for significant confounders.

Results: Teeth that received no treatment or non‐surgical treatment showed significant increases in probing depths, worsening of progno‐sis, worsening of furcation involvement, and increases in mobility when compared to surgically treated teeth. Teeth that received surgical treatment showed significant decreases in probing depths. No significant difference was noted between teeth that had no treatment and teeth that had non‐surgical treatment.

Conclusions: When individual teeth are used as the basis for analy‐sis, teeth that receive no treatment or non‐surgical treatment show a significant worsening of probing depths, furcations, mobility, and prognosis when compared to teeth that receive surgical treatment, while surgically treated teeth show significant improvement in probing depths. J Periodontal 2001;72:1509‐1519.
Root Coverage and Pocket Reduction as Combined Surgical Procedures
Authors: Hirsch A. , Attal U. , Chai E. , Goultschin J. , Boyan B.D. , Schwartz Z.
Published: February 2005

Background: One of the main objectives of periodontal reconstructive surgery is the coverage of exposed roots due to gingival recession. A large variety of mucogingival grafting procedures are available that give highly predictable and esthetically acceptable results when treating intact root surfaces. However, these procedures call for a second surgery site in the palate. The present study examines a series of cases in which connective tissue, obtained from the tuberosity during pocket reduction procedures in the posterior region of the maxilla, was used for root coverage.

Methods: Forty‐four teeth from 25 patients with gingival recession of 3.30 ± 0.14 mm (mean ± SEM) were treated with subepithelial connective tissue grafts using connective tissue obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla.

Results: The mean root coverage recession after treatment was 0.16 ± 0.06 mm, with effectiveness of coverage at 95.0% ± 1.84 and a predictability of 84.1%. Periodontal probing depth reduction at the donor site was 4.08 ± 0.24 mm.

Conclusions: These results indicate that the subepithelial connective tissue graft obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla provides a very predictable and esthetic root coverage without the need for a second surgical site. J Periodontol 2001;72: 1572‐1579.
Radiographic Defect Depth and Width for Prognosis and Description of Periodontal Healing of Infrabony Defects
Authors: Klein Filip , Kim Ti‐Sun , Hassfeld Stefan , Staehle Hans‐Jörg , Reitmeir Peter , Holle Rolf , Eickholz Peter
Published: February 2005

Background: The aims of the present study were to evaluate 1) defect depth and width as a prognostic factor and 2) change in defect width as a describing parameter of periodontal healing in infrabony defects treated by regenerative therapy after 6 and 24 months.

Methods: In 24 patients with advanced periodontitis, 39 infrabony defects were treated by guided tissue regeneration (GTR) using expanded polytetrafluoroethylene (ePTFE) (n = 7) or bioabsorbable barriers (n = 32). Clinical parameters were assessed and 39 standardized radiographs (in triplicate) were taken before and 6 and 24 months after surgery. Using a computer‐assisted analysis, the depth, width, and angle of the bony defects were measured.

Results: Statistically significant vertical clinical attachment gains (CAL‐V: 3.15 ± 1.63 mm to 3.31 ± 1.65 mm; P <0.001) and bony fill (1.30 ± 2.53 mm; P <0.01 to 1.54 ± 2.70 mm; P <0.005) were observed 6 and 24 months postsurgically. In a multilevel regression analysis CAL‐V gain was predicted by baseline CAL‐V (P <0.0001), actual smoking (P <0.05), and age (P <0.1). Bony fill could be predicted by baseline height of the infrabony component (P <0.0001), gingival index at baseline (P <0.05), and actual smoking (P <0.01). In narrow (<26°) and deep (≥3 mm) infrabony defects bony fill was more pronounced than in wide and shallow defects (P <0.05).

Conclusions: Improvement achieved by guided tissue regeneration in infrabony defects can be maintained up to 24 months after surgery. Narrow and deep infrabony defects respond radiographically and to some extent clinically more favorably to GTR therapy than wide and shallow defects. However, depth of the infrabony component was a stronger prognostic parameter than defect angle. Actual smoking impairs the results of GTR therapy in infrabony defects. J Periodontol 2001;72:1639‐1646.
Mandibular Second Molar Periodontal Status After Third Molar Extraction
Authors: Peng Kuang‐Yao , Tseng Yuen‐Chin , Shen E‐Chin , Chiu Shian‐Chung , Fu Earl , Huang Yu‐Wen
Published: February 2005

Background: Extraction and treatment of third molars have been cited as causing periodontal problems. To evaluate the long‐term effects of third molar extraction on the periodontal health of the mandibular second molar, a comparison of the periodontal status was performed around 2 groups of mandibular second molars, with and without third molar extraction.

Methods: A total of 312 sites in 57 adult periodontitis patients were examined and the buccal and lingual locations of the mesial and distal root surfaces around the second molars were recorded. Two‐hundred and thirty‐two sites were experimental teeth; i.e., third molars had been surgically removed more than 5 years ago, 80 sites served as control molars; i.e., congenitally missing third molars. Clinical periodontal parameters including probing depth, attachment loss, and gingival recession and radiographic intrabony level were measured. The effects of the surgery and the examination (buccal or lingual) locations on the measurements were statistically analyzed.

Results: Neither extraction history nor examination location affected the probing depth on mesial surfaces. However, significant effects of the surgical history on the probing depth were observed on the distal surfaces. Similar results of greater attachment loss and radiographic alveolar bone loss were observed only at the distal sites of the experimental group. In addition, the increased radiographic bone loss was only found at the distal sites (adjacent to the surgical location) and not at the mesial sites (distant from the surgical location) on the experimental group.

Conclusions: In this study, greater periodontal breakdown, including probing depth, attachment loss, and radiographic alveolar bone loss, was found at the distal sites, but not at the mesial sites, of the experimental molars where the third molar was surgically extracted compared with the control teeth (no surgery). In the experimental molars, more radiographic bone loss was found at the sites adjacent to the surgical location than at the sites distant to the surgical location. Therefore, we suggest that the surgical removal of the mandibular third molar may lead to a periodontal breakdown on the distal surface of the second molar. Periodontal re‐evaluation after the initial healing of third molar extraction is indicated. J Periodontol 2001;72:1647‐1651.
Internal Contamination of a 2‐Component Implant System After Occlusal Loading and Provisionally Luted Reconstruction With or Without a Washer Device
Authors: Rimondini Lia , Marin Carlo , Brunella Francesca , Fini Milena
Published: February 2005

Background: Microbial internal contamination of oral implants has been suggested as being responsible for inflammatory infiltration of peri‐implant tissues at the fixture‐abutment interface of 2‐stage and 2‐component implant systems; it is also considered as a potential source of pathogens. The present in vivo study evaluated contamination of the inner abutment‐implant retaining screw, after occlusal loading and provisionally‐luted reconstruction with or without a washer device.

Methods: Eight 2‐component oral implants sealed with an o‐ring silicon washer device and 9 without a seal were placed in 7 patients with high oral hygiene standards. Two months after prosthetic reconstruction, crowns and internal screws were removed, and organic and inorganic screw contamination was examined by scanning electron microscopy and energy dispersive x‐ray spectroscopy (EDS) analysis.

Results: An amorphous and crystalline contamination, suggestive of calcium and phosphate compounds, was seen on all screw surfaces. Microbial contamination was more frequently observed in the unsealed group. No differences in bacterial morphotypes were observed between the sealed and unsealed implants. Cocci were the most representative morphotypes, while rods were seldom seen.

Conclusions: In clinical situations, leakage occurs at the implant‐abutment interface, although bacterial contamination is limited in patients with high oral hygiene standards. Contamination may be reduced by using a washer device. J Periodontol 2001;72:1652‐1657.
A Longitudinal Study Comparing Scaling, Osseous Surgery, and Modified Widman Procedures: Results After 5 Years
Authors: Becker William , Becker Burton E. , Caffesse Raul , Kerry Gloria , Ochsenbein Clifford , Morrison Edith , Prichard John
Published: February 2005

Background: Scaling and root planing, osseous surgery, and modified Widman procedures are effective methods for treating periodontal diseases. Studies have been carried out to determine if these procedures are more effective than others in reducing clinical probing depths, while maintaining clinical attachment levels. The purpose of this report is to present 5‐year results from a longitudinal study comparing scaling and root planing (SRP), osseous surgery (OS), and modified Widman (MW) therapies. The study has been completed for 12 years.

Methods: Sixteen adult patients with moderate to advanced periodontal disease were treated with initial scaling and oral hygiene procedures in a private practice. Posthygiene data were used to compare changes in plaque and gingival indices, probing depth (PD), clinical attachment levels (CAL), and recession. Frequency distributions were used to compare changes at individual sites. The first published report was from baseline to one year. This follow‐up report is from baseline through 5 years.

Results: At 5 years, there were significant decreases in gingival and plaque scores. For the 3 procedures, there were significant decreases in baseline 4 to 6 mm PD (P <0.0001); however, there were no differences between the methods. Similar findings were noted for PD initially greater than 7 mm. At 5 years, OS had the greatest number of 1 to 3 mm sites (332 sites, 73.2%), while MW had the fewest number of 4 to 6 mm PD (98 sites, 21.8%). SRP had the fewest 7 mm and greater sites (15 sites, 3.4%). At 5 years, CAL loss for 1 to 3 mm PD was statistically significant for the 3 procedures. There were slight gains in CAL for 4 to 6 mm probing depths. These gains were not significant. Similar findings were seen for CAL for probing depths greater than 7 mm. OS had the greatest number of sites losing more than 2 mm of CAL (64 sites), followed by SRP (21 sites) and MW (34 sites), respectively.

Conclusions: This 5‐year clinical trial demonstrates that with good patient maintenance excellent clinical results can be achieved with various methods of treatment. Within the limits of this study, SRP, OS, and MW were effective at reducing probing depths with slight changes in clinical attachment levels. J Periodontol 2001;72:1675‐1684.
Efficacy of a 3% Potassium Nitrate Desensitizing Mouthwash in the Treatment of Dentinal Hypersensitivity
Authors: Pereira Richard , Chava Vijay K.
Published: February 2005

Background: Potassium nitrate has been used previously in a dentifrice or gel to alleviate dentinal hypersensitivity. The aim of this study was to compare a 3% potassium nitrate/0.2% sodium fluoride mouthwash with a 0.2% sodium fluoride control mouthwash in a 6‐week double‐blind study.

Methods: Fifty subjects were evaluated using 2 tactile methods and cold air sensitivity (dental air syringe), along with subjective perception of pain (0 to 10 scale) at baseline and at 2 and 6 weeks.

Results: There was a general decrease in dentinal hypersensitivity levels in both groups over the 6‐week study period as demonstrated by all 4 methods of assessment. There was also a statistically significant difference in decrease in sensitivity between the groups.

Conclusions: This study showed that a 3% potassium nitrate/0.2% sodium fluoride mouthwash appears to have therapeutic potential to alleviate dentinal hypersensitivity. J Periodontol 2001;72:1720‐1725.
Preprosthetic Periodontal Surgery in the Interproximal Area With Modification of the COL Area: Anatomic and Histologic Study in Dogs
Authors: Novaes Arthur B. , Novaes Arthur B. , de Oliveira Paulo T.
Published: February 2005

Background: Due to its concave morphology, a COL creates difficulties for proper oral hygiene. When this characteristic is accentuated by tooth position or caries and when restorations are necessary, they should be corrected by preprosthetic surgery. However, there are no data proving the efficacy of the procedures. The purpose of this study was to evaluate tissue response to preprosthetic surgery to modify COL morphology.

Methods: Five mongrel dogs received apically positioned flaps, osteotomy/plasty, and RAI (restorative alveolar interface technique) on the maxillary right third bicuspid and first molar; on the same teeth on the left side, a large tissue excision similar to gingivectomy and RAI were performed. Histologic specimens stained with hematoxylin and eosin and Mallory were evaluated at hour 0 and 1, 2, 3, and 4 weeks under light microscopy.

Results: At hour 0, hemorrhage in the remaining interproximal tissue on the left side, and denuded bone modified by the osteotomy on the right side, were observed. At 1 week, both sides showed the presence of granulation tissue and the beginning of reepithelialization and fiber formation. At 2 weeks, the papillae were rebuilt and epithelialized, with fewer inflammatory cells and dilated blood vessels, with a convex morphology. At 3 weeks, the papillae were convex and saddle shaped, with thicker epithelium and denser connective tissue. The general aspect was similar to attached gingiva. However, on the right side, the total extension of the interproximal tissues was longer and had a less accentuated convex curvature. At 4 weeks, the tissues were more mature, but the morphologic and histological findings were similar to 3 weeks.

Conclusion: Both techniques modified the COL morphology, suggesting that the RAI technique was effective; but the apically positioned flap with osteotomy and RAI created a more extensive convex surface and more interproximal space for the prosthesis. It is recommended that this technique be considered for use in humans. J Periodontol 2001;72:1734‐1741.
Elevated Hydroperoxide Levels and Antioxidant Patterns in Papillon‐Lefèvre Syndrome
Authors: Battino Maurizio , Ferreiro Maria‐Soledad , Bompadre Stefano , Leone Luciana , Mosca Fabrizio , Bullon Pedro
Published: February 2005

Background: Since it has been found that reactive oxygen species seem to be involved in the pathogenesis of both periodontitis and hyperkeratotic syndromes, we studied a group of patients belonging to 3 generations of a family with different degrees of severity of Papillon‐Lefèvre syndrome (PLS) to ascertain whether altered concentrations of the most important hydrophobic and hydrophilic plasma antioxidants as well as products of oxidative damage are present in PLS.

Methods: Coenzyme Q (CoQ), vitamin E, glutathione (GSH), and uric acid were evaluated by highperformance liquid chromatography (HPLC) (supplied with electrochemical detector) techniques and hydroperoxides by a spectrophotometric method.

Results: GSH and uric acid were in the range of reference values; CoQ was very low in both the child of the third generation and his mother, and these 2 subjects had the highest hydroperoxide levels. The child also had extremely low values of vitamin E. In general, all family members showed abnormally high hydroperoxide levels, with the exception of those members who are phenotypically healthy.

Conclusions: Since the subjects with the lowest hydroperoxide contents are phenotypically healthy, whereas the affected individuals presented lower antioxidant levels and very high hydroperoxide concentrations, it has been suggested that a specific antioxidant therapy could be a promising approach in treating some PLS subjects. Moreover, unexpected manifestations of heterozygosity in the child of the third generation were also detected. J Periodontol 2001;72:1760‐1766.
The Effect of Alcohol Consumption on Periodontal Disease
Authors: Tezal Miné , Grossi Sara G. , Ho Alex W. , Genco Robert J.
Published: February 2005

Background: Alcohol consumption, like smoking, may be related to periodontal disease independently of oral hygiene status. This study assessed the relationship between alcohol consumption and severity of periodontal disease.

Methods: A cross‐sectional study of 1,371 subjects ages 25 to 74 in the Erie County, NY population was performed. Alcohol intake was assessed by means of previously validated selfreported questionnaires. Outcome variables were gingival bleeding, clinical attachment loss, alveolar bone loss, and presence of subgingival microorganisms.

Results: Logistic regression analyses adjusting for age, gender, race, education, income, smoking, diabetes mellitus, dental plaque, and presence of any of 8 subgingival microorganisms showed that those consuming ≥5 drinks/week had an odds ratio (OR) of 1.65 (95% CI: 1.22 to 2.23) of having higher gingival bleeding, and OR of 1.36 (95% CI: 1.02 to 1.80) of having more severe clinical attachment loss compared to those consuming <5 drinks/week. Those consuming ≥10 drinks/week had an odds ratio (OR) of 1.62 (95% CI: 1.12 to 2.33) of having higher gingival bleeding and OR of 1.44 (95% CI: 1.04 to 2.00) of having more severe clinical attachment loss compared to those consuming <10 drinks/week. Alcohol consumption was not significantly related to alveolar bone loss nor to any of the subgingival microorganisms.

Conclusions: The results suggest that alcohol consumption is associated with moderately increased severity of periodontal disease. Longitudinal studies are needed to determine whether alcohol is a true risk factor for periodontal disease. J Periodontol 2001;72:183‐189.
Effect of Repeated Local Minocycline Administration on Periodontal Healing Following Guided Tissue Regeneration
Authors: Yoshinari Nobuo , Tohya Tosyo , Kawase Hitoshi , Matsuoka Masanori , Nakane Mitsuo , Nakane Mitsuo , Mitani Akio , Koide Masanori , Inagaki Koji , Fukuda Mitsuo , Noguchi Toshihide
Published: February 2005

Background: Infection after a periodontal surgical site has been prepared for guided tissue regeneration (GTR) is one of the common complications that can compromise healing. The purpose of this study was assess the effect of repeated local antimicrobial therapy following GTR for improving clinical attachment gains, and to histologically evaluate the various cell populations and bacterial contamination of the retrieved expanded polytetrafluoroethylene membrane (ePTFE).

Methods: Forty periodontal intrabony defects in 40 patients were treated by a flap procedure that included the use of ePTFE membranes to allow GTR. Patients were randomly assigned to 2 treatment groups: 20 patients were treated with the ePTFE alone (control group), and the other 20 were treated with the ePTFE combined with the administration of a weekly repeated local application of minocycline ointment for 8 weeks after membrane placement (test group). The membranes were retrieved 6 weeks after the initial surgery and sectioned serially in a coronal‐apical plane. The sections were then divided into 9 fields and examined by light microscopy for the presence of inflammatory cells and oral bacteria. Clinical measurements were taken at the time of baseline examination and at a 6 month follow‐up examination after removal of the ePTFE.

Results: At the 6‐month follow‐up examination, control and test groups showed significant improvement; i.e., reduction in the probing depth and increased clinical attachment gain compared with the values at the baseline examination. However, the mean clinical attachment gain of the test group (3.0 ± 0.3 mm) was significantly (P = 0.03) greater than that of the control group (2.0 ± 0.5 mm). Histologically, the total number of the cells of both groups was similar. In both groups, mononuclear cells were dominant and fibroblasts, neutrophils, and plasma cells were rarely encountered. There was a tendency for the number of macrophages to be somewhat higher in the control group. The total number of bacteria in the test group was significantly less than that in the control group. The number of bacteria in both control and test groups decreased toward the apical portion.

Conclusions: In the present study, clinical attachment gain of intrabony defects following GTR was favorable with repeated local administration of minocycline ointment. However, a complete microbial eradication was not achieved. J Periodontol 2001;72:284‐295.
Comparison of Calcium Sulfate and Autogenous Bone Graft to Bioabsorbable Membranes Plus Autogenous Bone Graft in the Treatment of Intrabony Periodontal Defects: A Split‐Mouth Study
Authors: Orsini Marco , Orsini Giovanna , Benlloch Dunia , Aranda Juan Jose , Lazaro Pedro , Sanz Mariano , De Luca Massimo , Piattelli Adriano
Published: February 2005

Background: Current literature shows that calcium sulfate can be used in guided tissue regeneration. Its biocompatibility and resorbability give it significant advantages in the treatment of periodontal and endodontic defects. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change, beyond that achieved with debridement alone, in treating intraosseous defects. The aim of the present investigation was to evaluate the clinical results obtained with autologous bone plus calcium sulfate, and to compare them with the results obtained using autologous bone plus membrane.

Methods: A total of 12 patients were treated in the present investigation. A split‐mouth design was utilized. Twelve 3‐wall periodontal defects were treated with calcium sulfate plus autologous bone graft (test) and compared with 12 contra‐lateral defects treated with a bioabsorbable membrane plus autologous bone graft (control). Before the surgical procedure, patients were instructed about oral hygiene and scaling and root planing (SRP) was completed. Probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded at baseline and 6 months.

Results: There were no statistical differences between test and control defects at baseline. BOP was 58% and 50% for control and test defects, respectively. Mean PD was 7.75 ± 0.96 mm (control) and 8.0 ± 1.28 mnn (test). Mean CAL was 8.58 ± 1.31 mm (control) and 8.83 ± 0.91 mm (test). At 6 months, mean PD was 3.41 ± 0.51 (P = 0.0022) for control defects and 3.58 ± 0.51 (P = 0.0022) for test defects. CAL showed a mean gain of 5 ± 0.85 for controls (P = 0.0022) and 5.25 ± 0.75 for test defects (P = 0.0022). Thus, there was a mean reduction of PD of 4.33 mm (56%) for control sites and 4.42 mm (55%) for test sites. The mean clinical attachment gain was 3.57 mm for control sites and 3.58 mm for test sites. As there were no shamoperated controls, it is not clear that the healing of these test or control‐treated sites was any better than similar 3‐walled defects sham operated.

Conclusions: Both therapies led to short‐term improvement of the measured parameters; neither was superior to the other. J Periodontol 2001;72:296‐302.
Thrombin‐Stimulated Growth, Clustering, and Collagen Lattice Contraction of Human Gingival Fibroblasts Is Associated With Its Protease Activity
Authors: Chang Mei‐Chi , Chan Chiu‐Po , Wu Hui‐Lin , Chen Ruey‐Song , Lan Wan‐Hong , Chen Yi‐Jane , Jeng Jiiang‐Huei
Published: February 2005

Background: Thrombin is a serine protease produced following gingival tissue injury or inflammation. It regulates the functional behavior of injury‐neighboring cells via the activation of specific protease‐activated receptors (PAR). Thrombin's role in gingival tissue healing and inflammatory response processes is not yet well understood.

Methods: We investigated the effects of thrombin on gingival fibroblast (GF) growth [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide (MTT) assay], collagen lattice contraction, and associated morphological changes.

Results: Thrombin (>1 U/ml), but not thrombin receptor (PAR‐1) agonist peptide (SFLLRN, single letter amino acid code, abbreviated as TRAP, 1 to 50 μg/ml), stimulated the growth and clustering of cultured human GF in vitro. Growth‐stimulatory effects of thrombin were inhibited by D‐Phe‐Pro‐ArgCH2Cl (PPACK), a serine protease inhibitor. By contrast, trypsin (>10 μg/ml), a PAR‐2 activator, suppressed the growth of GF. Thrombin (>0.2 U/ml) and TRAP (10 to 25 μg/ml), but not trypsin, prostaglandin E2 (0.01 to 0.5 μg/ml), or bovine serum albumin (BSA) (1 to 80 μg/ml), induced the GF‐populated collagen lattice contraction within 30 to 60 minutes of exposure. The thrombin‐induced collagen lattice contraction was inhibited by PPACK (20 μg/ml) and an actin filament polymerization inhibitor, cytochalasin B (1 μg/ml). The collagen lattice contraction induced by TRAP was also inhibited by cytochalasin B, but not by PPACK. Using a reversetranscriptase polymerase chain reaction (RT‐PCR), the expression of PAR‐1, and to a lesser extent PAR‐3, was observed for human GF, although little PAR‐2 and PAR‐4 expression was noted.

Conclusions: These results indicate that thrombin is important in periodontal wound healing and inflammatory processes by promoting the growth and contraction of GF. The stimulatory effects of thrombin are associated with its protease activation of thrombin receptors. J Periodontol 2001;72:303‐313.
Participation of Periodontal Ligament Cells With Regeneration of Alveolar Bone
Authors: Isaka Jun , Ohazama Atsushi , Kobayashi Makoto , Nagashima Chizu , Takiguchi Takashi , Kawasaki Hideyuki , Tachikawa Tetsuhiko , Hasegawa Kohji
Published: February 2005

Background: It is important to clarify the participation of periodontal ligament (PDL) cells in the regeneration of alveolar bone to establish a reliable approach for obtaining periodontal regeneration. The aim of this study was to determine whether PDL cells play an important role in alveolar bone repair during the course of periodontal regeneration.

Methods: In an in vitro study, the expression of the osteoblast phenotype, such as alkaline phosphatase activity and parathyroid hormone‐dependent 3′,5′‐cyclic adenosine monophosphate accumulation, was investigated in dog PDL cells (DPLC) and dog bone cells isolated from mandibles (DBC). In a related study, the roots of mandibular third premolars extracted from aged dogs were divided into a PDL(+) group, in which the PDL was preserved, and a PDL(‐) group, in which the PDL was removed. These roots were respectively transplanted into surgically created bone cavities with buccal and interproximal bone defects in an edentulous area, prepared in advance by extraction of mandibular fourth premolars. These bone defects with the transplanted roots were completely covered with submerged physical barrier membranes. New bone formation and new connective tissue attachment, which require new cementum and insertion of functionally oriented new collagen fibers of periodontal ligament, were histomorphometrically assessed, and were compared between the PDL(+) and PDL(‐) groups 6 weeks after transplantation.

Results: Both cultured DPLC and DBC exhibited the osteoblast phenotype. New connective tissue attachment was observed only in the PDL(+) group. However, alveolar bone was almost completely regenerated to the original bone height in both the PDL(+) and PDL(‐) groups, and the amount of newly formed bone was not significantly different between the 2 groups.

Conclusions: DPLC retain the capability to differentiate into an osteoblast lineage and may act in the regeneration of periodontal ligament with new cementum formation, whereas these cells may have a limited influence on alveolar bone formation during the course of periodontal regeneration. J Periodontol 2001;72:314‐323.
Characterization of Proliferation and Cellular Wound Fill in Periodontal Cells Using an In Vitro Wound Model
Authors: Oates Thomas W. , Mumford John H. , Carnes David L. , Cochran David L.
Published: February 2005

Background: The therapeutic success of periodontal regenerative therapy may be compromised by our limited understanding of the wound healing process. Wound healing requires the coordination of complex cellular and molecular interactions. Recently, using an in vitro wound model, our laboratory has shown that gingival fibroblasts (GF) fill an in vitro wound more rapidly than periodontal ligament cells (PDL). This suggests that there may be differences in the levels of proliferation for these 2 cell types during the wound healing process. Such specific cell type differences may be significant in clinical outcomes of regenerative therapy. Therefore, the aim of this research was to characterize and compare the levels of both proliferation and cellular wound fill between GF and PDL using our in vitro wound model.

Methods: Primary cultures of human PDL and GF cells were established from explanted tissue, and passaged to 12‐well tissue culture plates. Triplicate cultures of both cell types were grown to confluence and in vitro wounds were mechanically created, removing a 3 mm wide band of the cell layer across the diameter of the wells. The wells were then incubated for 2, 6, or 9 days in media containing either 0.1% or 10% fetal bovine serum (FBS). At each time point, cells were pulsed with 5‐bromo, 2‐deoxyuridine (BrdU), fixed, and nuclei stained to measure DNA synthesis (as a measure for proliferation). Cells were counter stained with cytoplasmic stain to measure cell number. Quantitative analysis distant from (area of interest [AOI 1]), next to (AOI 2), and within the wound boundaries (AOI 3 and 4) was accomplished using computer‐assisted histomorphometry.

Results: The levels of proliferation and cellular fill for each cell type were assessed relative to time and AOI. Overall, the PDL displayed greater (P <0.01) levels of proliferation than the GF. For both cell types, proliferation was found to be significantly (P <0.001) greater at day 2 compared to other time points. PDL displayed greater levels of proliferation than GF in all AOI, with this difference reaching significance (P <0.02) within the cell layer (AOI 1 and 2). When comparing levels of cellular fill in 10% FBS, GF displayed greater wound fill than the PDL. This difference was significant at day 6 (P <0.05) for both the marginal (AOI 3) and central (AOI 4) portions of the wound.

Conclusions: These findings, demonstrating unique differences between PDL and GF with respect to proliferation and wound fill in an in vitro model, suggest that there may be cell‐specific differences in cellular activity critical to periodontal wound healing. In addition, the results of this study show that the cellular proliferation response may not accurately reflect the overall wound healing response. J Periodontol 2001;72:324‐330.
Enamel Matrix Derivative Induces Matrix Synthesis by Cultured Human Periodontal Fibroblast Cells
Authors: Haase H.R. , Bartold P.M.
Published: February 2005

Background: Periodontal wound healing and regeneration require that new matrix be synthesized, creating an environment into which cells can migrate. One agent which has been described as promoting periodontal regeneration is an enamel matrix protein derivative (EMD). Since no specific growth factors have been identified in EMD preparations, it is postulated that EMD acts as a matrix enhancement factor. This study was designed to investigate the effect of EMD in vitro on matrix synthesis by cultured periodontal fibroblasts.

Methods: The matrix response of the cells was evaluated by determination of the total proteoglycan synthesis, glycosaminoglycan profile, and hyaluronan synthesis by the uptake of radiolabeled precursors. The response of the individual proteoglycans, versican, decorin, and biglycan were examined at the mRNA level by Northern blot analysis. Hyaluronan synthesis was probed by identifying the isotypes of hyaluronan synthase (HAS) expressed in periodontal fibroblasts as HAS‐2 and HAS‐3 and the effect of EMD on the levels of mRNA for each enzyme was monitored by reverse transcription polymerase chain reaction (RTPCR). Comparisons were made between gingival fibroblast (GF) cells and periodontal ligament (PDLF) cells.

Results: EMD was found to significantly affect the synthesis of the mRNAs for the matrix proteoglycans versican, biglycan, and decorin, producing a response similar to, but potentially greater than, mitogenic cytokines. EMD also stimulated hyaluronan synthesis in both GF and PDLF cells. Although mRNA for HAS‐2 was elevated in GF after exposure to EMD, the PDLF did not show a similar response. Therefore, the point at which the stimulation of hyaluronan becomes effective may not be at the level of stimulation of the mRNA for hyaluronan synthase, but, rather, at a later point in the pathway of regulation of hyaluronan synthesis. In all cases, GF cells appeared to be more responsive to EMD than PDLF cells in vitro.

Conclusions: EMD has the potential to significantly modulate matrix synthesis in a manner consistent with early regenerative events. J Periodontol 2001;72:341‐348.
Is Loss of Attachment Due to Root Planing and Scaling in Sites With Minimal Probing Depths a Statistical or Real Occurrence?
Authors: Gunsolley John C. , Yeung Gabriel M. , Butler James H. , Waldrop Thomas C.
Published: February 2005

Background: Following root planing and scaling many studies have implied an association between a loss of clinical attachment at sites with initially shallow pockets (1 to 3 mm) and gains in attachment level for deeper probing depths. However, these effects are also consistent with a statistical phenomenon referred to as regression towards the mean. This principle suggests that extreme values will moderate the next time they are recorded. The purpose of this report was to estimate the effect that regression towards the mean has on perceived changes in attachment level after root planing and scaling.

Methods: During the initial examination, 2 different investigators conducted 2 full‐mouth probings. Two quadrants were randomly selected to be root planed and scaled until the root surfaces were smooth by tactile touch of an explorer. The 2 remaining quadrants were not treated. At 4 to 6 weeks after treatment, another full mouth probing was done. An examiner who was blind to the quadrants that had been scaled measured attachment level and probing depth after therapy. This study design provided periodontal measurements before and after root planing and scaling, measurements before and after a period of 4 to 6 weeks of no therapy, and duplicate measurements at the beginning of the study.

Results: Using the repeat examination when no true change could occur, shallow sites (≤3 mm of probing depth) showed average negative differences between repeat attachment level measurements (‐0.23 mm), which mimicked loss of periodontal attachment. Deep sites, (>6 mm) showed average positive values (0.40) mimicking gain in attachment level. These results suggest that regression towards the mean is a significant effect in this data set. Both shallow non‐scaled and scaled sites had similar differences in repeat measures (‐0.28 mm, ‐0.25 mm) which were also similar to and not statistically different from changes after therapy for both non‐scaled (‐0.21 mm) and scaled sites (‐0.08 mm). Thus not only does this data set exhibit regression towards the mean, but it explains the majority of perceived loss of periodontal attachment after scaling at sites that have minimal probing depth.

Conclusions: These results suggest that the majority of perceived loss of attachment due to scaling at sites of minimal probing depth that have been reported in many studies may be due a statistical phenomenon called regression towards the mean. J Periodontol 2001;72:349‐353.
Dental Unit Waterline Contamination and Its Possible Implications During Periodontal Surgery
Authors: Putnins Edward E. , Di Giovanni Davide , Bhullar Amandeep S.
Published: February 2005

Background: Dental unit waterline contamination has become a concern to clinical dentistry. This concern arises from the fact that bacteria sloughed from established biofilms in dental unit waterlines increase heterotrophic bacteria counts in water exiting these units.

Methods: Scanning microscopy and bacterial viability staining were used to examine the sessile and planktonic biofilm present in dental unit waterlines and water samples, respectively. In addition, the limulus amebocyte assay was used to measure the lipopolysaccharide (LPS) levels in water samples.

Results: All dental unit waterlines were coated with a wellestablished biofilm made up of filamentous and bacillus‐like microorganisms. Water samples collected from these dental units contained high numbers of individual bacteria and bacterial aggregates. A viability staining technique identified signifi‐cantly more bacteria in water than could be cultured, and 64% of the total bacterial population stained as nonvital. Since the bacterial load (viable and nonviable) was high, we examined the LPS in dental unit water samples. The mean LPS levels in water collected from high‐speed and air/water lines in use were 480 and 1,008 endotoxin units (EU)/ml. This was significantly higher than the mean level of 66 EU/ml found in water samples collected from adjacent clinic sinks. The LPS level at the start of the day (2,560 EU/ml) was reduced by 70% with 1 minute of flushing (800 EU/ml). Flushing times of 5 and 10 minutes were not able to reduce LPS levels to zero.

Conclusion: The presence of high heterotrophic bacterial counts, sloughing biofilm, and high LPS levels are discussed in relation to patient risk and periodontal wound healing biology. J Periodontol 2001;72:393‐400.
Evaluation of Ultrasonic Scaling Unit Waterline Contamination After Use of Chlorine Dioxide Mouthrinse Lavage
Authors: Wirthlin M. Robert , Marshall Grayson W.
Published: February 2005

Background: An infection control problem in dental operatories which is not fully controlled is waterline contamination by heterotrophic mesophilic bacteria. These bacteria are present in water supplies as a planktonic phase and adhere to the lumen of tubings as a biofilm comprised of their external cell surface glycocalyx and by production of extracellular carbohydrate polymers. The adherent film is most difficult to remove. The accumulated planktonic phase can be reduced significantly by flushing water from the lines before use in patient treatment, but will return when the equipment is idle through the accumulation of more planktonic phase and by slough of the biofilm surface‐adsorbed phase not yet enmeshed in the carbohydrate matrix. Chlorine dioxide has antimicrobial activity against many bacteria, spores, and viruses. It is used in water supply treatment as a disinfectant and slime preventive and has an advantage over chlorine in that carcinogenic trihalomethanes are not generated.

Methods: This study compared use of phosphate buffer‐stabilized chlorine dioxide (0.1%) mouthrinse as a lavage in ultrasonic dental scaler units with the use of tap water as a control. Sterile water flushed through the units onto heterotrophic plate count (HPC) sampler plates was cultured 7 days at room temperature and colonies were counted at 12×. One test and one control unit were used for biopsy of internal tubing and scanning electron microscopy imaging.

Results: The HPC counts, in colony forming units (CFU)/ml, were reduced 3‐ to 5‐fold by flushing tap water through the units, but they returned after units were idle overnight. When phosphatebuffered chlorine dioxide mouthrinse was used as a lavage, CFU/ml were reduced 12‐ to 20‐fold. Holding chlorine dioxide in waterlines overnight reduced recurrent buildup compared to water (P <0.05). Scanning electron microscopy images indicated a significant reduction of biofilm coverage by chlorine dioxide as compared to water (P <0.001).

Conclusions: Phosphate‐buffered chlorine dioxide mouthrinse was effective in these short‐term trials for control of waterline contamination in ultrasonic dental scaling units. It should prove as useful in dental professional waterline applications as it has in industrial uses for biofilm control. J Periodontol 2001;72:401‐410.
Effect of Nicotine on Fibroblast β1 Integrin Expression and Distribution In Vitro
Authors: Austin Gregory W. , Cuenin Michael F. , Hokett Steven D. , Peacock Mark E. , Sutherland Donald E. , Erbland John F. , Billman Michael A.
Published: February 2005

Background: Integrins are a family of transmembrane cell surface glycoproteins, and those with the β1‐subunit function in both cell‐to‐cell and cell‐to‐substrate adhesion. The purpose of this study was to determine nicotine's effect on the expression and distribution of the β1 integrin subunit on the human gingival fibroblast cell surface.

Methods: Pure nicotine was diluted in medium to the following concentrations: 0 (control), 0.025, 0.05, 0.1, 0.2, and 0.4 μM. Human gingival fibroblasts (HFG) were grown for 24 hours in each concentration and fluorescein‐labeled with a mouse monoclonal anti‐human β1 antibody and secondarily incubated with a urease‐labeled anti‐mouse IgG antibody. After a final wash, the cells were incubated with urea/bromcresol blue substrate for 15 minutes at 37°C and measured in a microplate reader at 570 nm.

Results: The integrin β1‐subunit was detected on the HGF surface membrane by fluorescence labeling, and cell‐enzymelinked immunosorbent assay testing demonstrated its decreased expression with increasing nicotine concentrations that were statistically different at the concentrations of 0.2 and 0.4 μM versus controls (P <0.05).

Conclusions: Nicotine concentrations of 0.2 and 0.4 μM significantly decrease β1 integrin expression in human gingival fibroblasts that may affect cell‐cell and cell‐substratum adhesion during wound healing. J Periodontol 2001;72:438‐444.
Keratinocyte Growth Factor Expression in Human Gingival Fibroblasts and Stimulation of In Vitro Gene Expression by Retinoic Acid
Authors: Mackenzie Ian C. , Gao Zhirong
Published: February 2005

Background: Keratinocyte growth factor (KGF) is a stromally derived growth factor of the fibroblast growth factor (FGF) family with paracrine effects targeted to influence the growth and differentiation of epithelia. Regional and temporal changes in KGF expression play important roles in the development and maintenance of epithelial structures and in epithelial wound healing. Differing patterns of expression of KGF by fibroblasts in the gingival region could therefore be related to the observed regional variation in the differentiation and behavior of gingival epithelia.

Methods: The in vitro and in vivo patterns of expression of KGF mRNA in human gingival and periodontal fibroblasts were examined using reverse transcription polymerase chain reactions (RT‐PCR) and in situ hybridization with digoxigenin‐labeled riboprobes. The patterns observed for human gingiva were compared with those for human skin and for murine tissues.

Results: Gingival and periodontal fibroblasts showed expression of KGF transcripts in vitro, and the degree of expression was markedly influenced by the presence of retinoic acid, an agent known to influence patterns of epithelial differentiation. Sections of human and murine gingiva and skin showed regionally variable expression of transcripts with the cells expressing KGF in the subepithelial, rather than the deeper, connective tissues and periodontium.

Conclusions: The results point to a role of KGF in the maintenance of normal growth and differentiation of gingival epithelia. A lack of KGF expression by periodontal fibroblasts in vivo is expected to hinder apical epithelial migration and thus stabilize the epithelial attachment. The effects of retinoic acid (RA) on KGF expression in vitro provide an indirect mechanism by which RA may regulate the growth and differentiation of gingival epithelia. J Periodontol 2001;72:445‐453.
The Effect of Occlusal Discrepancies on Periodontitis. I. Relationship of Initial Occlusal Discrepancies to Initial Clinical Parameters
Authors: Nunn Martha E. , Harrel Stephen K.
Published: February 2005

Background: A causal relationship between occlusal discrepancies and periodontal disease has been postulated in the past. However, animal studies and clinical studies have not been able to clearly demonstrate or rule out this potential relationship.

Methods: The records from a private practice limited to periodontics were reviewed to find patients who had complete periodontal examination records, including occlusal analysis, that were recorded at least 1 year apart. Patients who fit these criteria were divided into a group who had none of the recommended treatment (untreated n = 30), those that had only nonsurgical treatment (partially treated n = 18), and a control group that had complete all recommended treatment (surgically treated n = 41). The data for each tooth of each patient, including occlusal status, were placed in a database and analyzed using the generalized estimating equations (GEE) method to test for associations between initial occlusal discrepancies and various initial clinical parameters while adjusting for significant confounders.

Results: Teeth with initial occlusal discrepancies were found to have significantly deeper initial probing depths (P <0.0001), significantly worse prognoses (P <0.0001), and significantly worse mobility than teeth without initial occlusal discrepancies. In addition, this association between initial occlusal discrepancies and initial periodontal condition was found to hold for various subsets considered as well, including posterior teeth only and when only patients with good oral hygiene were considered.

Conclusions: This study indicates that there is a strong association between initial occlusal discrepancies and various clinical parameters indicative of periodontal disease. Based on adjustments made for other known risk factors for periodontal disease, such as smoking, poor oral hygiene, etc., this study provides some evidence that occlusal discrepancy is an independent risk factor contributing to periodontal disease. J Periodontol 2001;72:485‐494.