Periodontal regeneration following implantation of cementum and periodontal ligament-derived cells.

BACKGROUND AND OBJECTIVE: The periodontal regeneration of bone defects is often unsatisfactory and could be largely improved by cell therapy. Therefore, the purpose of this study was to evaluate the regenerative potential of implanting canine cementum-derived cells (CDCs) and canine periodontal ligament-derived cells (PDLDCs) in experimentally created periodontal intrabony defects in beagle dogs. MATERIAL AND METHODS: Cells were obtained from premolars extracted from four beagle dogs. Three-wall intrabony periodontal defects, 3 mm wide and 4 mm deep, were surgically created in their second and fourth premolars and plaque was allowed to accumulate. Once the defects were surgically debrided, periodontal regeneration was attempted by random implantation of collagen sponges embedded with 750,000 CDCs, 750,000 PDLDCs or culture medium. After 3 mo of healing, specimens were obtained and periodontal regenerative outcomes were assessed histologically and histometrically. RESULTS: The histological analysis showed that a minimal amount of new cementum was formed in the control group (1.56 ± 0.39 mm), whereas in both test groups, significantly higher amounts of new cementum were formed (3.98 ± 0.59 mm in the CDC group and 4.07 ± 0.97 mm in the PDLDC group). The test groups also demonstrated a larger dimension of new connective tissue, resulting in a significantly more coronal level of histological attachment. CONCLUSION: This proof-of-principle study suggests that cellular therapy, in combination with a collagen sponge, promoted periodontal regeneration in experimental intrabony periodontal defects.

Tobacco as a risk factor for survival of dental implants.

BACKGROUND: It has been shown that smoking habits represent an increased risk for impaired bone healing and implant failure. This study aimed to evaluate the implant survival rates among non-smokers (NS) and different kinds of smokers (S). METHODS: A retrospective analysis was made over a 5-year period of the clinical and radiographic findings corresponding to 66 consecutive patients who had received a total of 165 dental implants. Patients were divided into two groups: S, 40 patients (95 implants; 58% of the sample); and NS, 26 patients (70 implants; 42% of the sample). Also, S and NS were classified into four different categories according to daily tobacco use: NS, 26 patients and 70 implants; light smokers (LS), 23 patients and 44 implants; moderate smokers (MS), 11 patients and 25 implants; and heavy smokers (HS), six patients and 26 implants. RESULTS: Sixteen implants (9.7%) failed and had to be removed. Group S showed 15 failures and a success rate of 84.2%. Group NS had only one failure, giving a success rate of 98.6%. The risk of implant failure was approximately 31% in those who smoked more than 20 cigarettes per day. HS showed statistical differences from NS or LS. However, they did not show any differences from MS. CONCLUSIONS: Within the limits of the present study, the use of tobacco involves a 15.8% risk of implant failure, with a 13.1 odds ratio. LS or MS tobacco use involves a 10.1% relative risk of implant loss, whereas the consumption of >20 cigarettes per day increases this risk to 30.8%.

Evaluation of surgical and non-surgical periodontal therapies, and immunological status, of young Down's syndrome patients.

BACKGROUND: Individuals with Down's syndrome (DS) differ in their oral condition compared with the healthy population. Periodontal disease in persons with DS under the age of 30 years is very high. Immune deficiencies are also present. For dental practitioners it is difficult to decide on a particular course of treatment. In this study, patients with DS were selected in order to 1) evaluate the effectiveness of surgical and non-surgical periodontal therapies and 2) assess their immunological status. METHODS: The population consisted of 14 DS patients (14 to 30 years old). Surgical and non-surgical periodontal therapies were compared in a split-mouth design. Clinical measurements of plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment levels (CAL) were taken at baseline, posttreatment, 6 months, and 1 year. Immunomodulatory activity of neutrophils was analyzed in vitro by chemotaxis (Boyden migration chamber), phagocytic activity, and production of super-oxide anion (NBT reduction) tests and compared between DS patients and healthy controls. RESULTS: Both surgical and non-surgical therapies showed a significant improvement in all the clinical parameters compared to baseline. There were no differences between surgical and nonsurgical therapy in PI or GI. There was a significant PD reduction with the non-surgical therapy at 1 to 3 mm PD. However in PD >3 mm the surgical therapy, although not statistically significant, showed better results. Neutrophil chemotaxis, phagocytic activity, and production of super-oxide anion were significantly decreased in the DS patients. CONCLUSIONS: After a year, both surgical and non-surgical therapies have similar periodontal clinical improvement in DS patients. There is partial impairment of immunological functions in DS individuals which does not seem to affect the clinical response to therapy.

Characterization of immunocompetent cells in the diseased canine periodontium.

The beagle dog with naturally occurring periodontal disease is one of the most widely used animal models in periodontal research for histological studies on disease pathogenesis and on the effect of potential therapeutic regimens. However, previous studies were restricted to morphological assessment of immunocompetent cells because of the lack of available cell-specific markers. In this study we systematically characterized the specificity and immunoreactivity of a panel of anti-human antibodies for identification (ABC method) of immunocompetent cells in formalin-fixed, EDTA-decalcified, paraffin-embedded inflamed periodontal tissues obtained from six beagle dogs. Canine lymph nodes and a panel of different human tissues served as positive controls. Polyclonal anti-CD3 immunolabeled canine T-lymphocytes specifically. Anti-CD79alpha (clone HM57) reacted with B-lymphocytes and plasma cells, and CD79alpha (clone JCP117) showed no staining in canine tissues. Neutrophils, monocytes, small macrophages, and keratinocytes reacted with an anti-myeloid/histiocyte antibody (clone MAC387). Anti-CD68 (clones PG-M1 and EBM11) immunolabeled large macrophages and plasma cells. Clone EBM11 also stained osteoclasts and cementoclasts. With the exception of JCB117, all antibodies revealed similarly favorable immunolabeling of canine and human immunocompetent cells. Long-term EDTA decalcification appeared to weaken immunostaining of plasma cells with HM57. MAC387 and CD68 can be used to distinguish macrophages in different differentiation stages in canine periodontal tissues. (J Histochem Cytochem 46:1443-1454, 1998)

Effects of amalgam restorations on the periodontal membrane in monkeys.

The response of the periodontal membrane to reimplanted teeth carrying amalgam restorations in the middle third of their roots was studied from seven days to six months after grafting. The study revealed that the amalgam restorations produced an initial localized inflammation in the periodontal tissues that subsided subsequently with the formation of a pseudocapsule.

Replantation of mature teeth without endodontics in monkeys.

The purpose of this study was to evaluate the histologic response after replantation of mature, developed teeth without endodontic treatment in monkeys. To serve as experimental controls, the other replanted teeth received endodontic treatment. No significant differences were noted in the rate and quality of periodontal tissues healing between the endodontically and the nonendodontically treated teeth in monkeys sacrificed at 5, 7, and 14 days, and at 1, 2, and 3 months after replantation. However, specimens obtained at 4, 6, 9, and 12 months showed that teeth replanted without endodontics developed periapical complications, whereas endodontically treated teeth did not.

Effects of composite restorations on the periodontal membrane in monkeys.

We evaluated the histopathological response of the periodontal membrane to intentionally-replanted teeth carrying composite (experimental) and silver amalgam (control) restorations in the middle third of each root. The study revealed that the amalgam produced, in the periodontal tissues, an initial localized inflammation that subsided with the subsequent formation of a fibrous capsule. However, the periodontal membrane adjacent to the composite resin restorations demonstrated chronic inflammation. It was concluded that the composite evoked chronic inflammatory responses of the periodontal tissues in monkeys.

Natural history of periodontal disease in adults: findings from the Tecumseh Periodontal Disease Study, 1959-87.

The purpose of this epidemiological study was to estimate the degree of change in periodontal attachment level in a sample of adults examined in 1959 and 1987 in Tecumseh, Michigan. Out of 526 individuals between the ages of five and 60 years in 1959, a sample of 325 resided within an 80-km-radius area in 1987. Of those, 167 were re-examined. Loss of periodontal attachment (LPA) was determined with a Michigan #0 probe on four tooth sites (disto-buccal, mid-buccal, mesio-buccal, mid-lingual) for all teeth present. Of the individuals contacted, 28 had lost all their teeth during the 28 years. Of the 167 adults examined, two refused periodontal probing. Out of the 165 adults with LPA measurements in 1987, only 22 (13.3%) had an average increased loss of 2 mm or more per person between 1959 and 1987; five adults (3.0%) had an average LPA increase of 3 mm or more, and only two adults (1.2%) had an average LPA increase of 4 mm or more. The attachment level in 59.3% of all the tooth sites examined in 1959 in the 165 individuals either did not change or changed within +/- 1.0 mm. On the basis of bivariate analyses, the individuals with high LPA increase (greater than or equal to 2 mm) had the following characteristics significantly different from those with low LPA increase: They were older, smoked, had tooth mobility at baseline, higher gingivitis, plaque, calculus, and tooth mobility scores at follow-up, lower education level, and irregular dental attendance.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of localized gingival recessions. Part IV. Results after three years.

Twenty-six localized recessions treated with either a lateral sliding flap or a coronally repositioned flap procedure more than 3 years ago were reevaluated. Biometric measurements on the recipient and the donor of control teeth included: a) cementoenamel junction, gingival margin; b) sulcus depth; c) gingival margin, mucogingival line. These recordings were statistically compared to those taken 180 days after the surgical procedures were performed. Pairwise t tests were used to determine whether there were any changes between the 180 days and the 3 years postoperative control with either procedure. A two sample t test was run to see whether the changes obtained with the two procedures differed from each other. No significant changes were found. The values for gingival recession, sulcus depth and width of keratinized gingiva remained stable for both techniques throughout the observation period.

Treatment of localized gingival recessions. Part I. Lateral sliding flap.

This study was undertaken to evaluate biometrically the changes that occur on the recipient as well as on the donor tooth with regard to gingival recession, sulcus depth and width of keratinized gingiva after performing a lateral sliding flap in the treatment of localized denuded roots. Fourteen teeth with gingival recession were treated using a lateral sliding flap. Measurements were recorded preoperatively and 1, 3 and 6 months after surgery. A mean gain of 2.69 mm of soft tissue coverage over the denuded root was found 6 months postoperatively which represents 69% of coverage. The mean gain in width of keratinized gingiva averaged 3.15 mm. On the donor tooth an average gingival recession of 1.1o mm was found after 6 months, and the width of keratinized gingiva decreased an average of 1.25 mm. Results remained stable after 30 days postsurgery.

Treatment of localized gingival recessions. Part II. Coronally repositioned flap with a free gingival graft.

Fourteen teeth with localized gingival recessions were treated using a coronally repositioned flap with a free gingival graft (Bernimoulin, 1973). The second step of the procedure was performed 1 month after the free gingival graft was done. Clinical measurements of the recession, sulcus depth and keratinized gingiva were taken preoperatively and at 30, 90 and 180 days after surgery. A mean reduction in the recession of 2.73 mm was obtained after 6 months, which was equivalent to a 64% decrease of the original recession. A significant increase in the width of the keratinized gingiva, averaging 3.27 mm, was found after 6 months. All results remained stable after 30 days postoperatively. The values for gingival recession, sulcus depth and width of keratinized gingiva on the teeth adjacent to the recessions remained unchanged, since they were undisturbed by the procedure.

Enzymatic penetration through intact sulcular epithelium.

To explore possible enzymatic penetration through intact sulcular epithelium tritium labeled hyaluronidase and collagenase were applied to the gingival sulcus of five white lip marmosets. One quadrant per monkey remained untreated. Each remaining quadrant was randomly assigned to one of the following modalities of application: (a) tritiated hyaluronidase, (b) tritiated collagenase, (c) unlabeled hyaluronidase followed by tritiated collagenase, (d) inactivated tritiated hyaluronidase, or (e) normal saline as experimental controls. The enzymes were applied by means of a Pasteur disposable pipette. Eight drops were administered over a 4-minute period, one every 30 seconds. After a 5-minute waiting period a second series of eight applications was given over a 4-minute period. Radioautographic and standard histologic materials were obtained. Results suggest that: 1. Hyaluronidase has the ability to penetrate through intact nonkeratinized sulcular epithelium, widening the intercellular epithelial spaces and disorganizing the connective tissue ground substance. 2. Collagenase per se does not have the ability to penetrate through the intact sulcular epithelium. Its effect remains confined only to the superficial layers of the epithelium. 3. However, when collagenase application is preceded by hyaluronidase, collagenase spreads easily through the epithelium and deeply into the connective tissue. Hyaluronidase acts unquestionably as a spreading factors.

Effect of Achromycin ointment on healing following periodontal surgery.

This study evaluated the effect of applying 3% Achromycin on healing following periodontal surgery. Twelve patients participated, and 15 contralateral sides with similar disease were compared. The parameters assessed included amounts of gingival crevice fluid quantitated with the Periotron, gingival bleeding tendencies, mobility scores and attachment levels. No significant differences in bleeding tendency, mobility or attachment levels were found. Significant changes were noted on amounts of gingival crevicular fluid, however. The amounts of gingival crevicular fluid collected were significantly lower on the side not treated with Achromycin throughout the observation period. Applying 3% Achromycin did not have a beneficial effect on the healing of periodontal wounds. Whether the application of an antibiotic on sutured flaps limited the bacterial contamination of the gingival tissues through a "wicking effect" of the silk suture material, or if this bacterial contamination had any consequence on gingival healing or reattachment of the periodontal tissues adjacent to the tooth, cannot be determined from this study.

Removal of amalgam overhangs. A profilometric and scanning electron microscopic evaluation.

Forty recently extracted teeth with Class II amalgam restorations with overhangs were divided into four groups of 10 teeth each. The overhangs were removed using one of the following instruments in each group: trimmer, chisel, surgical blade and reciprocating motordriven diamond tip. Instrumentation was performed until no irregularity could be detected clinically with a No. 3 explorer. The tooth-amalgam interfaces were examined by combined use of a surface measuring instrument and a scanning electron microscope. Four tracings from each specimen were recorded and the discrepancy at the tooth-restoration interface was measured. The mean score for each tooth was determined, and the results were analyzed statistically. The tooth-restoration interfaces were photographed at 140 magnification with the SEM. The results indicated that all instruments tested were effective in removing overhangs, since none of the mean discrepancies registered after instrumentation exceed 4 micron. The surgical blade, and especially the reciprocating motor-driven diamond tip eliminated overhangs better than the chisel. Both SEM photographs and the profilometric tracings revealed gaps or voids at the toothamalgam interface, ranging from 10 to 50 micron.

The reliability of a colorimetric test in determining gingival inflammation.

This investigation was undertaken to compare the Gindex saliva test scores with the Gingival Index scores and crevicular fluid flow scores, as proposed by Löe and Holm-Pedersen. Eighty-one patients were tested using the Gindex chemical analysis kit. Crevicular fluid was collected from the six teeth advocated by Ramfjord, followed by a clinical assessment of these teeth using the G.I. Of the original 81 subjects tested, 11 were given a prophylaxis consisting of scaling, root planing, polishing, and oral hygiene instruction; and were retested 14 days later. Results of the two-sample t test show that there were no significant differences between males and females in any of the three tested parameters. The sample was pooled and tested for multiple correlations between the G.I., crevicular fluid, and Gindex scores. Nonparametric rank correlation coefficient tests indicated a statistically significant correlation between the three parameters. A pair wise "t" test for the pre- and post-treatment sample demonstrated a significant reduction in the three parameters. A pair wise rank analysis also showed a significant reduction in the G.I., crevicular fluid, and Gindex scores.

Comparison of results following modified Widman flap surgery with and without surgical dressing.

The clinical effects of a periodontal dressing after modified Widman flap surgery were studied. A total of thirty surgical sites in 13 patients were included in the study. Half of the sites were not covered by a periodontal dressing while the other half were. To effect a blind evaluation, the dressings were placed and removed by someone other than the examiner. Gingival crevicular fluid flow and gingival inflammation were measured prior to surgery, 2 weeks, 1 month and 2 months after surgery. Clinical attachment level and pocket depth were measured prior to surgery, 1 month and 2 months after surgery. All patients were instructed in oral hygiene procedures and received rubber cup prophylaxes and flossing at 1 week, 2 weeks, 1 month and 2 months postoperatively. At the conclusion of the study, a questionnaire was administered to each patient. No significant differences were found between dressed and undressed segments regarding changes in clinical attachment levels, pocket depth, or gingival inflammation. The omission of a dressing did not result in a greater incidence of discomfort. More patients stated preference for no dressing.

Dextran penetration through nonkeratinized and keratinized epithelia in monkeys.

The purpose of this study was to determine if polysaccharide dextrans would pass through intact-nonkeratinized and induced-keratinized sulcular epithelia in monkeys. Dextran penetration through normally keratinized oral gingival epithelium also was evaluated in the same gingival specimens. Each of three Rhesus monkeys received a thorough prophylaxis 1 week prior to the experiment. During this week, the monkeys also received daily IV injections of Achromycin. After the antibiotic treatment, the teeth were polished and cleaned with a rubber cup using prophylactic paste for 2 consecutive months, as follows: (1) the right maxillary and mandibular teeth received daily prophylaxes on weekdays and (2) the left maxillary and mandibular teeth received one prophylaxis weekly. These frequencies of plaque removal on one-half of the mouth maintained clinically healthy gingiva and produced keratinization of the sulcular epithelium. At the end of the 2-month prophylaxes, a 5% solution of dextrans derived from Leuconostoc mesenteroides was applied topically to the gingiva once daily for 3 consecutive weeks. During this time, the monkeys continued having dental prophylaxes following the previous time schedule. The study showed that induced-keratinized sulcular epithelium as well as normally keratinized oral gingival epithelium resisted penetration of dextrans, whereas intact-nonkeratinized sulcular epithelium apparently lacked a surface layer resistant to penetration.

Mucoperiosteal flaps with and without removal of the pocket epithelium.

The purpose of this study was to clinically evaluate the need for elimination of the pocket epithelium during mucoperiosteal flap surgery aimed at reattachment or readaptation. A split mouth design was used in 13 patients with two bicuspids and two molars included in each quadrant. Two surgical techniques were compared. One of the quadrants received a modified Widman flap with removal of the pocket epithelium, while the contralateral side received a crevicular flap without removing the pocket epithelium. One month after the hygienic phase was completed, the following measurements were taken: Gingival Index, Plaque Index, gingival crevicular fluid flow, mobility, furcation involvement, level of attachment, pocket depth and gingival recession. In addition to these measurements, which were taken immediately prior to the surgery (baseline), 1- and 3-month postsurgical measurements were also taken. Gingival recession was recorded immediately after the flaps were replaced and sutured. All data were analyzed statistically using paired t test and sign test. The biometric results showed that without the removal of the pocket epithelium, good clinical results relative to gain in clinical attachment levels and reduction in probing depth were achieved. Greater gingival recession occurred on the crevicular flap side postsurgically when compared to the modified Widman flap. The other clinical parameters remained the same at the three time intervals. This was true within each technique and when both techniques were compared.

Effects of expanded polytetrafluoroethylene and polylactic acid barriers on healthy sites.

The configuration of the barrier devices to treat interproximal defects by guided tissue regeneration (GTR) necessitates inclusion of healthy adjacent teeth to secure the barriers in place. The purpose of this study was to evaluate the effects of expanded polytetrafluoroethylene (ePTFE) and polylactic acid (PLA) barrier devices on probing depth (PD), clinical attachment level (CAL), and crestal bone height in healthy sites. The study included 30 patients who were in an earlier study which compared the effects of GTR utilizing an ePTFE or a PLA barrier in intrabony defects. Thirty defects were randomly assigned to receive either a PLA (test) or an ePTFE barrier (control) after open flap debridement. The sites in this investigation included those healthy sites in the immediately adjacent non-affected teeth covered by the barriers. CAL and PD were measured at baseline and 12 months. Intrasurgical crestal bone height was recorded at the time of barrier placement and at a 12-month re-entry. Two-sample t-test comparisons of PD and CAL measurements between barrier device covered sites at baseline (PD: ePTFE, 2.32+/-0.51; PLA, 2.59+/-0.74; CAL: ePTFE, 2.71+/-0.66; PLA, 2.59+/-0.65 mm), and at one year (PD: ePTFE, 2.14+/-0.37; PLA, 2.07+/-0.56; CAL: ePTFE, 3.14+/-1.05; PLA, 2.75+/-0.73 mm) were not statistically different (P > 0.05). Paired t-test was utilized to compare changes in PD, CAL, and crestal bone height from baseline to 12 months. A statistically significant reduction in PD was found in the PLA group (delta = -0.52, P = 0.01) while no significant change was found in the ePTFE group (delta = -0.18, P = 0.18). Change in CAL was statistically significant in the ePTFE group (delta = 0.43, P = 0.02) while no significant change was found in the PLA group (delta = 0.16, P = 0.39). Crestal bone height changes from baseline to 12 months were statistically different for both groups (ePTFE, delta = 0.8 mm, P = 0.001; PLA, delta = 0.6 mm, P = 0.001). These resorptive changes, when compared between treatment groups were not statistically different (P > 0.05). In conclusion, the placement of ePTFE or PLA barriers on healthy sites resulted in probing depth reductions and loss of attachment of 0.5 mm or less. Additionally, both groups exhibited less than 1.0 mm of crestal bone resorption.

Keratinizing potential of sulcular epithelium.

It has been shown that the connective tissue base determines the epithelial surface characteristics. Although there is no apparent difference between the connective tissues underlying the subcular and the surface gingival epithelium, the sulcular epithelium is not keratinized as is the gingival surface. The influence of the sulcular environment in determination of keratinization was explored in three adult Rhesus monkeys. Twenty-four intrasulcular mucoperiosteal flaps were elevated beyond the buccal mucogingival border, were turned inside out and sutured to leave the sulcular epithelium exposed on the surface. Short term speciments (1 hour to 7 days) were obtained from one monkey which received H3 thymidine 1 hour prior to sacrifice. Biopsies were obtained from the other two monkeys covering intervals of 1 week to 2 months. The findings indicate that the sulcular epithelium has potential for keratinization. The contact to the tooth appears to determine the lack of keratinization of the sulcular epithelium.