Surgical crown lengthening: a 12-month clinical wound healing study.

BACKGROUND: Surgical crown lengthening has been proposed as a means of facilitating restorative procedures and preventing periodontal injuries in teeth with structurally inadequate clinical crowns or exposing tooth structure in the presence of deep, subgingival pathologies which may hamper the access for proper restorative measures. The few clinical studies in the current literature on postsurgical soft tissue modifications after crown lengthening procedures report conflicting results. The present study was designed to assess the alterations of the marginal periodontal tissues as an immediate outcome of surgical crown lengthening and over a 12-month healing period. METHODS: The patient sample included 30 patients (84 teeth) who presented with various conditions hampering proper restorative measures in one or more teeth and, therefore, requiring surgical exposure of tooth substance. After initial supportive therapy, the patients were recalled for a baseline examination, and the following parameters were evaluated at interproximal and buccal/lingual sites of each experimental tooth: plaque index, gingival index, position of the gingival margin, probing depth, and attachment level. After baseline examination, the patients underwent apically positioned flap surgery with osseous and connective tissue attachment resection. During surgery, the amount of resection and the achieved lengthening of the clinical crown were evaluated. The patients were enrolled in a maintenance program including professional tooth cleaning every 2 to 4 weeks. The patients were reexamined 1, 3, 6, 9, and 12 months postoperatively. RESULTS: 1) Immediately after surgery, a significantly (P < 0.001) increased clinical crown length of 3.7 +/- 0.8 mm (mean) at interproximal and 4.1 +/- 0.9 mm (mean) at buccal/lingual sites was achieved; 2) healing resulted in a statistically significant coronal displacement of the gingival margin of 3.2 +/- 0.8 mm at interproximal (P < 0.001) and 2.9 +/- 0.6 mm at buccal/lingual (P < 0.002) sites; and 3) as a consequence of this postsurgical soft tissue regrowth, the amount of the available tooth structure immediately after surgery decreased to 0.5 +/- 0.6 mm at interproximal sites (P < 0.0015) and to 1.2 +/- 0.7 mm at buccal/lingual sites (P < 0.001) at the 12-month examination. CONCLUSIONS: The results of the present clinical investigation demonstrated that during a 1-year period of healing following surgical crown lengthening, the marginal periodontal tissue showed a tendency to grow in a coronal direction from the level defined at surgery. This pattern of coronal displacement of the gingival margin was more pronounced (P < 0.001) in patients with "thick" tissue biotype and also appeared to be influenced by individual variations in the healing response (P < 0.001) not related to age or gender.

The use of barrier membranes and enamel matrix proteins in the treatment of angular bone defects. A prospective controlled clinical study.

UNLABELLED: In the present prospective clinical trial, the effect of various regenerative procedures performed at sites with angular bone defects were evaluated. The main outcome variable was probing attachment alteration. MATERIAL AND METHODS: 40 subjects, aged 32-61 years participated. They met the following inclusion criteria: (i) presence of generalized, advanced periodontal tissue destruction; (ii) presence of 2 similar, contralateral, angular bone defects (experimental sites) located in either the maxilla or the mandible; (iii) the defect site must exhibit a probing pocket depth (PPD) of > or = 6 mm, a probing attachment level (PAL) of > or = 7 mm, and a depth of the intrabony component of > or = 3 mm. All subjects had a good oral hygiene standard, were in good general health and did not use any medication. Prior to the start of the study, all subjects received non-surgical treatment for periodontal disease. Baseline clinical measurements (plaque, gingivitis, PPD, PAL and soft tissue recession) of the selected experimental sites were obtained 6 months after the completion of basic therapy. The 40 subjects were randomly divided into 4 treatment groups including 10 subjects each: 3 membrane groups and one Emdogain group. 1 h before surgery, the patients were given 3 g of Amoxicillin. No other antibiotics were prescribed. The test and control sites were treated during the same surgical session. Full thickness flaps were elevated and the exposed root surfaces were planed. Membrane placement: The root surface was rinsed with saline. A barrier membrane (Guidor or Resolut or Periodontal (e-PTFE) material) was positioned to cover the defect and the adjacent 2-3 mm of bone tissue. The control treatment was identical to the test treatment with the exception of barrier placement. Emdogain placement: The exposed root surfaces at both the test and control sites were, during a 2-min period, conditioned with a 24% EDTA gel. Emdogain was applied to the exposed root surface of the test site. In the control site, the vehicle, the PGA gel, was used as placebo control. The flaps were closed and sutured to obtain a complete coverage of the intrabony defect. RESULTS: Re-examinations, which were performed 12 months after surgery, disclosed that regenerative therapy, including either the use of barrier membranes or application of enamel matrix proteins to an instrumented root surface in an angular, intrabony defect, enhanced outcome variables such as probing pocket depth and probing attachment gain. It was furthermore demonstrated that clinical improvements were better at sites with deep, than at sites with shallow, intrabony defects. CONCLUSION: The 4 regenerative modalities tested appeared to be equally effective in terms of PPD reduction and PAL gain, and superior to open flap curettage alone.

Long-term effects of root-resective therapy in furcation-involved molars. A 10-year longitudinal study.

The present investigation was designed to evaluate the long-term effect of root-resective therapy in the treatment of furcation-involved molars. The patient sample included 72 patients, 21-62 years of age, who presented periodontal lesions in the posteriors segments of the mouth including furcation involvement of various degrees. After an initial examination, each patient was subjected to a series of full-mouth scaling and root planing. They were recalled 1-3 months later for a presurgical examination and subsequently underwent the corrective phase of therapy. During the surgical procedure, the furcation-involved teeth were subjected to root-resective therapy in conjunction with osseous recontouring and apically positioned flaps (test sites). A surgical procedure identical to the test procedure was performed in the non-furcation-involved teeth (control sites) with the exception of the root resection. At the completion of the active phase of treatment, 175 test and 175 control sites were available for the study. After a period of 6 months of healing and plaque control supervision following surgical procedures, the patients were recalled for a baseline examination. They were then enrolled in a maintenance program including professional tooth cleaning every 26 months. The patients were re-examined 3, 5 and 10 years post-operatively. The results of the assessments demonstrated that the survival rate, during the 10-year period of observation, reached 93% at test and 99% at control sites. The positive treatment outcome at the root-resected, furcation-involved teeth as well as at non-furcation-involved teeth was probably the consequence of the reestablishment of a tissue morphology favorable for oral hygiene and careful plaque control by the patients.

Guided tissue regeneration in the treatment of degree II furcations in maxillary molars.

he present clinical trial was designed to evaluate the clinical effect of GTR in the treatment of degree II furcation defects in maxillary molars. 28 patients, 21 to 59 years of age, referred for treatment of advanced periodontal disease were included. They presented with similar periodontal lesions in the right and the left maxillary molar regions, but had only one surface which exhibited furcation involvement. A total of 28 pairs of contralateral furcation defects of degree II including 18 interproximal pairs (10 mesial, 8 distal) and 10 buccal pairs, were available for the study. After the completion of basic therapy, the furcation involved molars in the right and left quadrants in each patient were randomly assigned to either a test or a control treatment procedure. Following flap elevation, scaling, root planing and granulation tissue removal, an e-PTFE membrane at the test site was adjusted to cover the entrance to the furcation defect and adjacent bone and was retained in this position with sling sutures. The mucoperiostal flaps were subsequently adjusted and positioned to cover the entire surface of the membrane and were secured in this position. An identical surgical procedure was performed in the control tooth regions with the exception of the placement of a teflon membrane. No periodontal dressing was used. Starting the day before surgery and continuing for 7 days, the patients received 1 + 1 g of Amoxicillin per day; morning and evening. The sutures were removed after 10 days. At the test sites, the membranes were removed after 6 weeks of healing. The treated sites were examined and re-entry procedures performed 6 months after reconstructive surgery. Open flap debridement at maxillary furcations of degree II resulted in some gingival recession and probing depth reduction, but no change occurred in parameters describing probing attachment or bone levels. The addition of GTR at buccal furcations enhanced the treatment result by promoting probing attachment and bone gain and reduced the amount of soft tissue recession above what was accomplished by flap debridement alone. No such benefit of membrane therapy was observed at mesial and distal furcations.

Guided tissue regeneration in the treatment of degree III furcation defects in maxillary molars.

11 subjects with generalized periodontitis and advanced lesions in the maxillary molar regions, including bilateral mesial-distal, but not buccal, degree III furcation defects in the 1st and/or 2nd molars, were recruited for the present clinical trial. The patients were given oral hygiene instruction and full-mouth scaling and root planing. A re-examination was performed after 3 months of healing, after which the furcation involved molars were randomly selected for a GTR or conservative treatment modality. An informed consent form was signed by each participating patient. The GTR procedure involved the elevation of mucoperiostal flaps, root surface debridement, and the placement of an e-PFTE membrane at the 2 entrances of the furcation defect. The flaps were repositioned and secured. The contralateral molar was treated in an identical manner but without the placement of the teflon membrane. The patients received amoxicillin (1g x 2/day for 8 days), were placed on chlorhexidine mouth rinsing and were recalled for prophylaxis 1x every 2 weeks. The teflon membranes were removed at a 2nd stage procedure after 6 weeks. All subjects were re-examined 6 months after the regenerative procedure, and in addition, all sites were evaluated following a reentry procedure. The final examination and measurements made during the reentry procedure documented that, although some reduction in probing pocket depth and some gain in probing attachment had occurred at both test and control sites, none of the furcation defects had closed, but retained the characteristics of a degree-III furcation involvement.

The effect of flap management and bioresorbable occlusive devices in GTR treatment of degree III furcation defects. An experimental study in dogs.

The present experiment on guided tissue regeneration had 2 objectives namely: (i) to study if an improved anchorage of the soft tissue flaps during the initial healing period after membrane placement would reduce the tendency for soft tissue recession and allow for healing of also large furcation defects; (ii) to determine if the use of biodegradable membranes in GTR procedures may promote new attachment formation in degree III furcation defects. 2 experiments were performed which included 5 and 8 dogs each. In each animal, the 3rd premolar of the left or right side of the mandible was selected as test site using the contralateral tooth as control. 2 months prior to the start of the experiment, the 2nd and 4th premolars in each side of the mandible were extracted. The extractions were performed to create a large edentulous space mesial and distal to the 3rd premolar. During GTR therapy the incisions prepared in this edentulous region were used to allow proper suture retention and flap stability during the initial phase of healing. In study 1, furcation defects (degree III) were prepared and subsequently treated according to GTR using e-PTFE membranes in the test and no membrane in the control site. In study 2, a bioresorbable membrane (Resolut) was installed in the test and an e-PTFE membrane in the control sites. The non-resorbable membranes were removed after 30 days. The animals were sacrificed 5 months after reconstructive surgery, biopsies were harvested, sectioned and analyzed histologically for new connective tissue attachment and bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimentally induced peri-implant mucositis. A clinical study in humans.

The purpose of this study was to compare the clinical and microbiological (microscopic) parameters during the development of experimental gingivitis and experimental peri-implant mucositis. Twenty partially edentulous patients were treated for moderate to advanced periodontal disease. Following active periodontal therapy consisting of motivation, instruction in oral hygiene practices, scaling and root planing and periodontal surgery where indicated, IMZ oral implants were incorporated in posterior edentulous areas. After 3 months of healing, the prosthetic abutments were connected, and the patients were closely supervised for another 2 months of healing. At this time, baseline data were obtained. Re-examinations were scheduled at 3 and 6 months. Following this, the patients were asked to refrain from oral hygiene practices for 3 weeks. At all examinations including the end of the period of no oral hygiene, the following clinical parameters were obtained: Plaque Index, Gingival Index and Sulcus Bleeding Index, all modified by Mombelli et al. (1987), probing pocket depths and recession in mm. Furthermore, submucosal/subgingival plaque samples were obtained and analyzed using phase contrast microscopy. At the end of the 3-week period of plaque accumulation, optimal oral hygiene was reinstituted. There were no statistically significant differences between the mean values of all parameters at implant compared to tooth sites at any observation periods. The period of no oral hygiene demonstrated a similar cause-effect relationship between the accumulation of bacterial plaque and the development of peri-implant mucositis as established for the gingival units by the experimental gingivitis model.

Guided tissue regeneration in surgically-produced furcation defects. An experimental study in the beagle dog.

The aim of the investigation was to evaluate the potential for new attachment formation at various degree III furcation involvements in the beagle dog. 3 differently shaped furcation defects were prepared; one small and one large key-hole defect, and one furcation defect which was part of "circumferential" loss of attachment and bone. 15 beagle dogs were used in the experiments. The furcation defects were surgically created at mandibular premolars in the right and left side of the jaw. Test teeth were subsequently treated according to the GTR principle, while control teeth were treated without the application of membranes. The result from the histological examination of biopsy specimens revealed that GTR treatment may result in complete new attachment at surgically produced "through and through" furcation involvements in dogs. The study, however, also revealed that the size of the furcation defect as well as the shape of the surrounding alveolar bone were factors that determined the outcome of this kind of treatment. The treatment failures were consistently associated with flap recession during healing which resulted in the exposure of the furcation defect.

Guided tissue regeneration in the treatment of furcation defects in mandibular molars. A clinical study of degree III involvements.

The present investigation was designed to evaluate the regenerative potential of the periodontal tissues in degree III furcation defects at mandibular molars using a treatment procedure based on the principle of guided tissue regeneration. The patient sample included 21 patients, 26-65 years of age, who presented periodontal lesions in the right and left molar regions including "through and through" furcation defects. After an initial examination, each patient was subjected to a series of full-mouth scaling and root planing. 2-3 months later, they were recalled for a baseline examination. The furcation-involved molars were randomly assigned in each patient to either a test or a control treatment procedure. The test procedure included the elevation of muco-periosteal flaps at the buccal and lingual aspects of the molars. Granulation tissue was removed and the exposed root surfaces were debrided and planed. The width and the height of the entrance openings to the furcation defects were assessed. A teflon membrane was adjusted to cover the entrances to the defects (buccal and lingual) and was retained in the manner described by Pontoriero et al. (1988). The flaps were repositioned on the outer surface of the membrane and secured by sutures which were removed after 10 days. Following surgery, the patients were instructed to rinse the mouth twice daily for 4 weeks with chlorhexidine gluconate. The membranes were removed after a healing period of 1-2 months. A surgical procedure identical to the test procedure was performed in the control tooth regions with the exception of the placement of membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Guided tissue regeneration in degree II furcation-involved mandibular molars. A clinical study.

The present clinical trial was designed to evaluate the regenerative potential of the periodontal tissues in degree II furcation defects at mandibular molars using a surgical treatment technique based on the principles of guided tissue regeneration. The patient sample included 21 subjects, 22-65 years of age. The patients selected had periodontal lesions in the right and left molar regions including advanced periodontal tissue destruction within the interradicular area. After an initial examination, each patient received a series of full-mouth scalings and root planings. 2-3 months later, they were recalled for a baseline examination including assessment of plaque, gingivitis, probing depths and probing attachment levels. The furcation involved molars were randomly assigned in each patient to either a test or a control treatment procedure. The test procedure included the elevation of mucoperiosteal flaps at the buccal and lingual aspect of the alveolar process. The inner surface of each flap was carefully curetted to remove epithelium and granulation tissue. The root surfaces were scaled and planed. A teflon membrane was adjusted to cover the entrance of the furcation area and the adjacent root surfaces as well as a portion of the alveolar bone apical to the crest. The flaps were repositioned and placed on the outer surface of the membrane and secured with interdental sutures which were removed after 10 days of healing. Following surgery, the patients were instructed to rinse the mouth twice daily with chlorhexidine gluconate. A second surgical procedure was performed after a healing period of 1-2 months to remove the teflon membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

The angular bony defect in the maintenance of the periodontal patient.

The present retrospective study was performed to evaluate some long-term alterations of the alveolar bone level at periodontal sites with angular and even ("horizontal") patterns of bone loss. The investigation included 48 patients who, following treatment for advanced periodontal disease, were placed in a maintenance care program which included recall appointments every 3-6 months for a period of 5 to 16 years. The material of the study comprised all teeth at which angular osseous defects (test sites) could be detected in a full-mouth series of radiographs obtained at the end of the active treatment phase. Alterations in the position of the marginal alveolar bone crest and the base of the osseous defect which took place during the maintenance period were assessed by comparing the post-treatment radiographs with a 2nd set of radiographs obtained at the final examination. In the same patients, an equal number of contralateral or neighboring teeth at which bone loss in the radiographs had an even or "horizontal" character were included as controls. The results from the assessments demonstrated that periodontal sites which, following active therapy displayed either angular or "horizontal" patterns of alveolar bone loss underwent, during a 5-16 year period of maintenance, only minor bone level alterations. Additional loss of supporting bone occurred equally frequently at sites with "horizontal" and angular patterns of bone loss. Thus, the findings reported failed to show up sites with angular bony defects as being particularly susceptible to recurrent destructive periodontitis.

Guided tissue regeneration in the treatment of furcation defects in man.

The regenerative potential of the periodontal tissues in degree II and III furcation defects at mandibular molars was assessed in a clinical trial using a surgical treatment technique based on the principles of guided tissue regeneration. The patient sample included 37 subjects who had periodontal lesions in the right and left mandibular molar regions, including advanced periodontal destruction within the radicular area. Following a baseline examination, the furcation-involved molars were randomly assigned in each patient to either a test or a control treatment procedure. The test procedure included the elevation of mucoperiosteal flaps and the placement of a teflon membrane to cover the entrance of the furcation area and the adjacent root surfaces as well as a portion of the alveolar bone apical to the crest. The flaps were repositioned and secured with interdental sutures. A procedure identical to the one used at the test teeth was performed at the control tooth regions with the exception of the placement of the teflon membrane. Following surgery, all patients were placed on a plaque control regimen which involved daily rinsing with chlorexidine gluconate and, in addition, professional tooth cleaning once every 2 weeks for 6 months. After 6 months of healing, the test and control sites were re-examined. The findings demonstrated that the treatment of degree II furcation defects at mandibular molars using the principles of guided tissue regeneration in 19 sites out of 21 resulted in the resolution of the furcation defect. Conventional therapy reached the same goal in less than 20% of the cases treated.(ABSTRACT TRUNCATED AT 250 WORDS)