Supracrestal Soft Tissue Research Articles

Preclinical Investigation on the Effect of Collagen Matrix With Polydeoxyribonucleotide at Buccally Positioned Implants.

The objective of this study is to investigate the effect of collagen matrix with polydeoxyribonucleotide (PDRN) at two concentrations on keratinized tissue (KT) regeneration for buccally positioned implants in canines. Four implants were placed in the edentulous mandible of five dogs simultaneously with KT removal. The implants were positioned buccally with respect to the ridge crest. After 2 months, KT augmentation was performed applying the following treatment modalities:(1) free gingival graft (FGG), (2) xenogeneic collagen matrix (XCM), (3) XCM loaded with 2 mg/mL PDRN (PDRN2), and (4) XCM loaded with 4 mg/mL PDRN (PDRN4). All animals were sacrificed 3 months later. Outcomes included clinical (KT height) and histomorphometric measurements (KT height/length, level of the mucosa, mucosal thickness, supracrestal soft tissue height). Clinical and histomorphometric KT formation at 3 months was greatest in groups with FGG (4.70 ± 1.00/3.94 ± 0.93 mm) and PDRN2 (4.85 ± 1.43/3.95 ± 0.87 mm). Group PDRN2 (1.87 ± 1.50 mm) showed a higher marginal mucosal level with respect to the implant platform compared to other groups (range: 0.57 ± 0.97-0.69 ± 1.14 mm). All groups presented a soft tissue thickness of < 2 mm on the buccal aspect of the implants. Based on the limitations of this pilot preclinical study, XCM with 2 mg/mL of PDRN demonstrated a potential for KT augmentation.

Wide Restorative Emergence Angle Increases Marginal Bone Loss and Impairs Integrity of the Junctional Epithelium of the Implant Supracrestal Complex: APreclinical Study.

To assess the influence of the emergence angle on marginal bone loss (MBL) and supracrestal soft tissue around dental implants. In six mongrel dogs, the mandibular premolars and molars were extracted. After 3 months of healing, four dental implants were placed in each hemimandible. The implants were randomly allocated to receive one of four customized healing abutments, each with a different value of the restorative emergence angle: 20°, 40°, 60° or 80°. Intra-oral radiographs were taken after placing the healing abutments and at 6, 9, 16 and 24 weeks of follow-up. Then, micro-CT and undecalcified histology and synchrotron were performed. MBL over time was analysed with generalized estimating equations (GEEs) and adjusted for baseline soft-tissue thickness. From implant placement to 24 weeks, GEE modelling showed that the MBL at mesial and distal sites consistently increased over time, indicating MBL in all groups (p < 0.001). The model indicated that MBL varied significantly across the different restorative angles (angle effect, p < 0.001), with 80° showing the greatest bone loss. Micro-CT, histology and synchrotron confirmed the corresponding trends and showed that wide restorative angles (60° and 80°) impaired the integrity of the junctional epithelium of the supracrestal tissue. A wide restorative angle increases MBL and impairs the integrity of the junctional epithelium of the implant supracrestal complex.

Changes in soft tissue dimensions following horizontal guided bone regeneration with a split-thickness flap design – evaluation of 8 cases with a digital method

BackgroundPeri-implant soft tissue corrections are often indicated following alveolar ridge augmentation, due to the distortion of the keratinized mucosa at the area of augmentation. The objective of the current study was to evaluate the dimensional soft tissue changes following horizontal guided bone regeneration (GBR) utilizing 3D digital data.Methods8 mandibular surgical sites with horizontal alveolar ridge deficiencies were treated utilizing a resorbable collagen membrane and a split-thickness flap design. Baseline and 6-month follow-up cone-beam computed tomography (CBCT) scans were reconstructed as 3D virtual models and were superimposed with the corresponding intraoral scan. Linear changes of supracrestal vertical- horizontal soft tissue alterations were measured in relation to the alveolar crest at the mesial- middle- and distal aspect of the surgical area. Soft tissue dimensions were measured at baseline and at 6-month follow-up.ResultsPreoperative supracrestal soft tissue height measured midcrestally averaged at 2.37 mm ± 0.68 mm, 2.37 mm ± 0.71 mm and 2.64 mm ± 0.87 mm at the mesial-, middle- and distal planes. Whereas postoperative supracrestal soft tissue height was measured at 2.62 mm ± 0.72 mm, 2.67 mm ± 0.67 mm and 3.69 mm ± 1.02 mm at the mesial, middle and distal planes, respectively. Supracrestal soft tissue width changed from 2.14 mm ± 0.72 mm to 2.47 mm ± 0.46 mm at the mesial, from 1.72 mm ± 0.44 mm to 2.07 mm ± 0.67 mm and from 2.15 mm ± 0.36 mm to 2.36 mm ± 0.59 mm at the mesial, middle and distal planes, respectively. Additionally the buccal horizontal displacement of supracrestal soft tissues could be observed.ConclusionsThe current study did not report significant supracrestal soft tissue reduction following horizontal GBR with a split-thickness flap. Even though there was a slight increase in both vertical and horizontal dimensions, differences are clinically negligible.Trail registrationThe trail was approved by the U.S. National Library of Medicine (www.clinicaltrials.gov); trial registration number: NCT05538715; registration date: 09/09/2022.

Guided versus freehand single implant placement: A 3-year parallel randomized clinical trial

ObjectivesThe present parallel randomized clinical trial aimed to assess, after a 3-year follow-up period, whether the choice of surgical technique—either manual or guided—and of the operator - non-expert operator or skilled - can affect the stability of peri‑implant marginal bone levels in implants placed 1 mm sub-crestal. Materials and methodsPatients received platform-switched implants (Anyridge, MegaGen Implant Co., Gyeongbuk, South Korea) featuring a 5-degree internal conical connection and supporting single screw-retained fixed crowns. The implants were randomly assigned to be placed through a digitally static guided surgery procedure (Test group - GS) or a freehand surgical technique (Control Group - FH). A non-expert operator (fewer than 20 implants placed in his professional activity) was selected to perform procedures for the GS Group, while a skilled operator (with over 1000 implants placed in his professional activity) was chosen for the FH Group. Marginal bone level (MBL) was measured at prosthesis installation (t0) and at 1 (t1), 2 (t2) and 3 years (t3) of follow-up. Changes in MBL from t0 to t3 were analyzed through periapical radiographs. Moreover, MBL changes at all time points were correlated to different supra-crestal soft tissue heights (STH): less than 3 and ≥ 3 mm, respectively. Results60 implants in 18 patients were examined, with 30 implants allocated to the GS group and 30 to the FH group. The difference in MBL change between the two groups was 0.11 ± 0.22 mm, which was not statistically significant (p = 0.61). At the time of prosthetic loading, the mean MBL for implants with STH less than 3 mm was 0.33 mm higher than implants with STH ≥ 3 mm, though this difference was not statistically significant (P = 0.065). ConclusionsDigitally static guided implant placement, performed by a non-expert operator, does not limit marginal bone remodeling, when compared to a freehand procedure performed by an experienced operator. Clinical significanceAfter correct and careful planning, early marginal bone levels (MBL) around conical connection, platform-switched implants placed sub-crestally may be stable in time. Digital planning and surgery have the potential to assist non-expert clinicians in achieving implant placements with comparable outcomes to those performed by experts.

Relationship between soft tissue dimensions and tomographic radial root position classification system for immediate implant installation.

The aim of this study was to evaluate the relationship between soft tissue dimensions and radial root position (RRP) classification for immediate implant placement on maxillary anterior teeth. Maxillary anterior teeth (n = 420) were analyzed in the radial plane of cone beam computed tomography (CBCT) scans. Each tooth was classified according to its RRP: class I, (IA, IB); class II (IIA, IIB) class III; class IV, and class V. Soft tissue thickness at different landmarks, supracrestal soft tissue height, and crestal bone thickness were measured in CBCT. Keratinized tissue width was clinically measured. Gingival phenotype (thick or thin) was evaluated by transparency of the periodontal probe and at the landmark 2mm from the gingival margin in CBCT. Class I tooth position accounted for 31.7%, class II for 45%, class III for 13.3%, class IV for 0.5%, and class V for 9.5%. The gingival phenotype was associated with RRP (χ2 test, p < 0.05). Soft tissue dimensions were significantly different over RRP classes (ANOVA and Tukey tests, p < 0.05). Types IA and IIA presented both thick soft and hard tissues. When planning immediate implants in the anterior maxilla, soft tissue dimensions evaluation should be incorporated into RRP classification to increase the accuracy and predictability of treatment outcomes.

A Novel Prehydrated Porcine-Derived Acellular Dermal Matrix: A Histological and Clinical Evaluation.

It is well known that soft tissue quality and quantity around dental implants is of paramount importance for later peri-implant health. For this purpose, the clinical and histological outcomes of the peri-implant mucosa, following soft tissue augmentation for soft tissue improvement with a novel prehydrated porcine acellular dermal matrix graft (PPADMG) in conjunction with simultaneous implant placement, were evaluated in this case series. Twenty-two patients were included in the study. They underwent a late implant placement protocol combined with PPADMG for soft tissue augmentation. A punch biopsy was taken at the time of uncovery of the submerged healed implant after a mean of 157 days healing time. Supracrestal soft tissue height (STH) was measured at the time of implant placement and uncovery. All sites showed a clinical increase in STH. The histological structure of the biopsies resembled a similar structure as found in the healthy oral mucosa. No unexpected tissue reactions could be found. Within the limits of this clinical and histological study, it may be concluded that STH improvement with this novel porcine-derived acellular dermal matrix, in combination with simultaneous implant placement, is a viable option to create a peri-implant tissue thickness and stability.

Hard and soft tissue healing around teeth prepared with the biologically oriented preparation technique and restored with provisional crowns: An in vivo experimental investigation.

To evaluate the hard and soft tissues healing around teeth prepared with the biologically oriented preparation technique (BOPT) versus the chamfer technique versus non-prepared teeth. Thirty-two teeth in eight beagle dogs were randomly prepared with the BOPT (test = 16) or chamfer (control = 16) techniques and covered with polymethylmethacrylate crowns as provisional restorations. Sixteen negative controls (non-prepared teeth) were also used for comparison. Histological description and histomorphometrical measurements of the periodontal tissues were collected at 4 and 12 weeks in 7 out of 8 dogs, including the soft tissue height and thickness, and the horizontal and vertical bone dimensions. When compared with negative controls, test and control preparation techniques exhibited a more apical location of the free gingival margin with respect to the cement-enamel junction (∆ = 1.1 mm for both groups at 4 weeks (p < .05), 0.99 mm for the test group (p = .043) and 0.20 mm for control group (p = 1.000) at 12 weeks). There were no significant differences between test and control groups with respect to vertical and horizontal histometric measurements. The BOPT and chamfer tooth preparation protocols induced similar qualitative and quantitative changes in the healing of the supra-crestal soft tissue complex, when compared with non-prepared teeth. Despite the limited amount of power, it appeared that differences between the tested preparation techniques were not statistically significant.

Relationship between supracrestal soft tissue dimensions and other periodontal phenotypic features: A cross-sectional study.

The purpose of this study was to determine the association between periodontal supracrestal soft tissue dimensions (PSSTDs) and other phenotypic features in non-molar maxillary teeth. Adult subjects in need of comprehensive dental treatment were recruited. Periodontal phenotypic variables (i.e., facial and palatal gingival thickness [GT], alveolar bone thickness [BT], and PSSTDs, namely distance from the gingival margin to the bone crest defined as periodontal supracrestal tissue height [PSTH] and distance from the cementoenamel junction to the bone crest [CEJ-BC]) were recorded using cone-beam computed tomography scans. Standardized intraoral photographs were obtained to assess facial keratinized tissue width (KTW) and other anatomical parameters (i.e., tooth type, gingival architecture, and interproximal papilla height). The study sample was constituted of 87 participants that contributed with a total of 522 maxillary anterior teeth. Differences in mean values of PSSTDs, KTW, GT, and BT were observed between tooth types and gender. Males exhibited a thicker GT and BT, and taller PSTH and KTW compared to females. Shorter CEJ-BC was associated with shorter PSTH, wider KTW, and thicker GT and BT. Shorter PSTH was associated with thicker facial BT. Notably, BT and GT were positively correlated at both facial and palatal sites, meaning that the thicker the gingival phenotype, the thicker the bone morphotype. Facial BT and facial GT were positively correlated with KTW. A flat gingival architecture was associated with the thick periodontal phenotype. Square teeth had shorter CEJ-BC, wider KTW, and thicker GT. Periodontal phenotypic features vary across and within subjects, between facial and palatal sites at different apico-coronal levels, and as a function of gender and tooth type. The shorter the PSSTDs, the wider the KTW and the thicker the GT and BT. PSSTDs, particularly PSTH, should be considered an integral component of the periodontal phenotype.

Immediate placement of one-piece zirconia implants with or without xenograft into the buccal gap. Soft tissues as secondary outcomes of an experimental in vivo study.

To histologically evaluate soft tissue healing following immediately placed one-piece zirconia implant and grafting a xenograft into the buccal gap. The third and fourth premolars (PM3 and PM4) in both quadrants of the mandible of nine dogs were used for this experiment. Those teeth were removed flapless and implants were placed into the distal sockets in a lingual position. In one side of the jaw, the gap between the implant and the socket walls was grafted (test) while no grafting was performed in the contralateral side (control), randomly selected. After 6months of healing, biopsies were obtained and prepared for histological analysis. Soft tissue measures like supracrestal soft tissue height (STH), length of barrier epithelium (BE), and connective tissue (CTC) were measured at buccal and lingual surfaces. The marginal mucosa was in a coronal position on the test side compared with the control side. At the buccal surface, the BE was longer in the test side than in the control side, while the CTC was longer in the control side than in the test side. For the STH (BE + CTC), the difference between the groups was not statistically significant. The placement of a xenograft into the gap between a 1-piece zirconia implant and the buccal wall in dogs modified the process of soft tissue healing, providing less soft tissue recession. The gap size seems to have a modifying effect on the application of this protocol.

Clinical Advances in Implant Transmucosal Contouring for Single Implant Sites: Prosthetic and Biologic Considerations.

Current evidence suggests that proper implant transmucosal contouring can significantly impact supracrestal soft tissue development and crestal bone response both in early and late stages of treatment. The macrodesign and composition of the anatomical healing abutment or temporary prosthesis used during transmucosal contouring are crucial elements for establishing biologic and prosthetic conditions that minimize early bone remodeling, improve esthetic outcomes, and reduce the possibility for future peri-implant inflammation. This article presents clinical directions on the design and fabrication processes of anatomical healing abutments or temporary prostheses for single implant sites under the interpretation of currently available scientific data.

Effect of periodontal phenotype characteristics on post-extraction dimensional changes of the alveolar ridge: A prospective case series.

This study was primarily aimed at assessing the effect that specific periodontal phenotypical characteristics have on alveolar ridge remodelling after tooth extraction. Patients in need of extraction of a non-molar maxillary tooth were enrolled. Baseline phenotypical characteristics (i.e., mid-facial and mid-palatal soft tissue and bone thickness, and supracrestal soft tissue height [STH]) were recorded upon extraction. A set of clinical, digital imaging (linear and volumetric), and patient-reported outcomes were assessed over a 14-week healing period. A total of 78 subjects were screened. Forty-two subjects completed the study. Linear and volumetric bone changes, as well as vertical linear soft tissue and alveolar ridge volume (soft tissue contour) variations, were indicative of a marked dimensional reduction of the alveolar ridge over time. Horizontal facial and palatal soft tissue thickness gain was observed. Thin facial bone (≤1 mm) upon extraction, compared with thick facial bone (>1 mm), was associated with greater linear horizontal (-4.57 ± 2.31 mm vs. -2.17 ± 1.65 mm, p=.003) and vertical mid-facial (-0.95 ± 0.67 mm vs. -4.08 ± 3.52 mm, p < 0.001) and mid-palatal (-2.03 ± 2.08 mm vs. -1.12 ± 0.99 mm, p=0.027) bone loss, as well as greater total (-34% ± 10% vs. 15% ± 6%, p < 0.001), facial (-51% ± 19% vs. 28% ± 18%, p=0.040), and palatal bone volume reduction (-26% ± 14% vs. -8% ± 10%, p < 0.001). Aside from alveolar bone thickness, STH was also found to be a predictor of alveolar ridge resorption since this variable was directly correlated with bone volume reduction. Patient-reported discomfort scores progressively decreased over time, and the mean satisfaction upon study completion was 94.5 ± 0.83 out of 100. Alveolar ridge remodelling is a physiological phenomenon that occurs after tooth extraction. Post-extraction alveolar ridge atrophy is more marked on the facio-coronal aspect. These dimensional changes are more pronounced in sites exhibiting a thin facial bone phenotype (Clinicaltrials.gov NCT02668289).

Influence of buccal emergence profile designs on peri-implant tissues: A randomized controlled trial.

The prosthetic emergence profile design might be an important factor in postsurgical mucosal recession etiology. Therefore, a restorative buccal emergence profile designed correctly might reduce gingival margin recession. To compare the marginal gingival level and the width/height (W/H) ratio between two profile configurations of single implant-supported restorations at molar sites. Twenty-one patients requiring a single mandibular molar tooth replacement with supracrestal mucosal thickness ≥2 mm were recruited and randomly assigned to a prosthesis buccal emergence profile design based on the buccal mucosal W/H ratio (Test Group) or maintained the original emergence profile of the healing abutment (Control Group). Assessments were made before delivery of the definitive restoration (T0), at prosthesis placement (T1), one (T2), and 12 (T3) months after loading. The gingival margin level change (△GM), initial emergence angle, buccal mucosal W/H ratio, marginal bone loss (MBL), implant failure, and complications were assessed. The gingival recession in the test group (0.13 ± 0.32 mm) was significantly lower than in the control group (0.63 ± 0.38 mm) at T3 (p=0.006). The initial emergence angle in the test group (31.4 ± 7.22 degrees) was significantly lower than the control group (40.0 ± 7.60 degrees) (p=0.025). The W/H ratio in the test group at T2 was significantly higher than at T0 but remained stable thereafter. The W/H ratio presented a continued rising trend in the control group. When the initial supracrestal soft tissue thickness was ≥2 mm, a restorative emergence profile based on the W/H ratio significantly reduced gingival margin recession. An emergence angle of 32.4 degrees showed better behavior in maintaining the gingival margin than 40 degrees. ChiCTR190002210.

Effect of Rough Surface Platforms on the Mucosal Attachment and the Marginal Bone Loss of Implants: A Dog Study.

The preservation of peri-implant tissues is an important factor for implant success. This study aimed to assess the influence of the surface features of a butt-joint platform on soft-tissue attachment and bone resorption after immediate or delayed implant placement. All premolars and first molars of eight Beagle dogs were extracted on one mandible side. Twelve-weeks later, the same surgery was developed on the other side. Five implants with different platform surface configurations were randomly inserted into the post-extracted-sockets. On the healed side, the same five different implants were randomly placed. Implants were inserted 1 mm subcrestal to the buccal bony plate and were connected to abutments. The primary outcome variables were the supracrestal soft tissue (SST) adaptation and the bone resorption related to the implant shoulder. The SST height was significantly larger in immediate implants (IC95% 3.9–4.9 mm) compared to delayed implants (IC95% 3.1–3.5 mm). Marginal bone loss tended to be higher in immediate implants (IC95% 0.4–0.9 mm) than in delayed implants (IC95% 0.3–0.8 mm). Linear-regression analysis suggested that the SST height was significantly affected by the configuration of the platform (0.3–1.9 mm). Roughened surface platforms resulted in higher SST height when compared to machined surface platforms. Marginal bone loss was less pronounced in roughened designs.

Enamel Matrix Derivative and Autogenous Bone Graft for Periodontal Regeneration of Intrabony Defects in Humans: A Systematic Review and Meta-Analysis.

The combination of enamel matrix derivative (EMD) with an autogenous bone graft in periodontal regeneration has been proposed to improve clinical outcomes, especially in case of deep non-contained periodontal defects, with variable results. The aim of the present systematic review and meta-analysis was to assess the efficacy of EMD in combination with autogenous bone graft compared with the use of EMD alone for the regeneration of periodontal intrabony defects. A literature search in PubMed and in the Cochrane Central Register of Controlled Trials was carried out on February 2019 using an ad-hoc search string created by two independent and calibrated reviewers. All randomized controlled trials (RCTs) comparing a combination of EMD and autogenous bone graft with EMD alone for the treatment of periodontal intrabony defects were included. Studies involving other graft materials were excluded. The requested follow-up was at least 6 months. There was no restriction on age or number of patients. Standard difference in means between test and control groups as well as relative forest plots were calculated for clinical attachment level gain (CALgain), probing depth reduction (PDred), and gingival recession increase (RECinc). Three RCTs reporting on 79 patients and 98 intrabony defects were selected for the analysis. Statistical heterogeneity was detected as significantly high in the analysis of PDred and RECinc (I2 = 85.28%, p = 0.001; I2 = 73.95%, p = 0.022, respectively), but not in the analysis of CALgain (I2 = 59.30%, p = 0.086). Standard difference in means (SDM) for CALgain between test and control groups amounted to −0.34 mm (95% CI −0.77 to 0.09; p = 0.12). SDM for PDred amounted to −0.43 mm (95% CI −0.86 to 0.01; p = 0.06). SDM for RECinc amounted to 0.12 mm (95% CI −0.30 to 0.55. p = 0.57). Within their limits, the obtained results indicate that the combination of enamel matrix derivative and autogenous bone graft may result in non-significant additional clinical improvements in terms of CALgain, PDred, and RECinc compared with those obtained with EMD alone. Several factors, including the surgical protocol used (e.g. supracrestal soft tissue preservation techniques) could have masked the potential additional benefit of the combined approach. Further well-designed randomized controlled trials, with well-defined selection criteria and operative protocols, are needed to draw more definite conclusions.

Enamel Matrix Derivative in Intrabony Defects: Prognostic Parameters of Clinical and Radiographic Treatment Outcomes

The purpose of this retrospective case series study is to identify possible preoperative parameters that could predict postoperative probing depth (PD), clinical attachment level (CAL) gain, or radiographic defect resolution in intrabony defects treated with enamel matrix derivative (EMD). Sixty-one chronic periodontitis patients, each contributing a 2- or 3-wall intrabony defect treated with EMD, were included. Clinical parameters recorded included the following: PD; CAL; gingival margin position; supracrestal soft tissue (SST); surgical distances of cemento-enamel junction (CEJ) to bone crest (CEJ-BC), CEJ to base of the defect (CEJ-BD), and BC to BD (BC-BD); and depth of 2- and 3-wall components. Radiographic parameters recorded included the following: CEJ-BC, CEJ-BD, BC-BD distances, and radiographic defect angle. Postoperative assessments were performed at 12 months. The probability of postoperative PD >4 mm increased 1.6-fold (odds ratio [OR] = 1.6; 95% confidence interval [CI] = 1.2 to 2.3) with each 1-mm baseline PD increase. Baseline PD and surgical CEJ-BD were statistically significant predictors of CAL gain; the greater the baseline PD (OR = 0.5; 95% CI = 0.3 to 0.8) and bone loss (OR = 0.6; 95% CI = 0.3 to 0.9), the less likely that postoperative CAL gain was ≤3 mm. Smoking and SST were significantly associated with defect resolution; failure to achieve ≥65% defect resolution was six-fold greater for smokers (OR = 6.5; 95% CI = 1.7 to 24.5) and almost double (OR = 1.7; 95% CI = 1.1 to 2.8) for each millimeter of SST increase. In EMD-treated intrabony defects, baseline PD predicts both CAL gain and postoperative PD. Smoking and SST are predictors of defect resolution.

Autogenous bone graft in conjunction with enamel matrix derivative in the treatment of deep periodontal intra‐osseous defects: a report of 13 consecutively treated patients

The purpose of the present study was to investigate the effectiveness of a regenerative procedure based on supra-crestal soft tissue preservation in association with combined autogenous bone (AB) graft/enamel matrix derivative (EMD) application in the treatment of deep periodontal intra-osseous defects. Thirteen consecutively treated patients, seven females and six males, aged 30-65 years, three smokers, were included. A total of 15 deep, one- to two-wall intra-osseous defects were selected. Immediately before surgery and 6 months after surgery, pocket probing depth (PPD), clinical attachment level (CAL), and gingival recession (REC) were recorded. PPD amounted to 9.4+/-1.8 mm before surgery, and decreased to 4.7+/-1.2 mm post-surgery (p<0.0000). CAL varied from 10.5+/-2.0 mm pre-surgery to 6.2+/-1.7 mm post-surgery (p<0.0000), with CAL gain averaging 4.3+/-1.4 mm. Fourteen (93.3%) defects presented CAL gain >/=3 mm. REC change was 0.4+/-0.7 mm. Results from the present study indicated that a regenerative procedure based on supra-crestal soft tissue preservation and combined AB/EMD treatment leads to a clinically and statistically significant improvement of soft tissue conditions of deep periodontal intra-osseous defects.

Supracrestal soft tissue preservation with enamel matrix proteins in treatment of deep intrabony defects.

The purpose of the present study was to investigate the effectiveness of a regenerative procedure based on supracrestal soft tissue preservation in association with enamel matrix proteins (EMP) in the treatment of deep intrabony defects. The subjects included 35 consecutively treated patients, 23 females and 12 males, aged 28-61 years, 11 of whom were smokers. Patients presented with at least one intrabony defect with probing pocket depth > or = 6 mm and a radiographic depth of the defect > or = 4 mm at the initial visit. Immediately before surgery and 9-12 months after surgery, Local Plaque Score (LPS), Local Bleeding Score (LBS), probing pocket depth (PPD), clinical attachment level (CAL), gingival recession (REC), and radiographic depth of the defect (DEPTH) were recorded. Thirty-one (88.6%) defects were LPS-negative presurgery, while 29 (82.9%) defects presented with no plaque postsurgery. The prevalence of LBS-positive defects shifted from 94.3% presurgery to 8.4% postsurgery (p < 0.0000). PPD was 8.9 mm before surgery, and decreased to 3.5 mm postsurgery (p < 0.0000). CAL varied from 10.1 mm presurgery to 5.4 mm postsurgery (p < 0.0000), with an average improvement (gain) of 4.7 +/- 1.7 mm. Twenty-six (74.3%) defects presented a gain of least 4 mm. Regression analysis showed a positive correlation between CAL gain as a dependent variable, and presurgery PPD and amount of supracrestal soft tissues as predictors. DEPTH improvement (gain) was 3.9 +/- 1.8 mm, which represented 65% of defect fill. Twenty (57.1%) defects presented a DEPTH gain of at least 4 mm. DEPTH gain was significantly correlated to presurgery PPD (p < 0.000). No significant differences were found between smokers and non-smokers in terms of CAL and DEPTH gain. Results from the present study indicated that the regenerative procedure based on supracrestal soft tissue preservation and EMP application leads to clinically and statistically significant improvement of hard and soft tissue conditions of deep intrabony defects.

Recession of the soft tissue margin at oral implants. A 2-year longitudinal prospective study.

The aim of this study was to longitudinally evaluate alterations in the position of the periimplant soft tissue margin, occurring during a 2-year period after insertion of fixed prostheses. 41 patients, subjected to treatment with partial or full-arch implant supported fixed prostheses based on a total of 163 standard Brånemark oral implants, were included in the study. A baseline examination was performed at time of insertion of the prosthetic construction and involved assessments of plaque, mucositis, probing depth, bleeding on probing marginal soft tissue level, width of masticatory mucosa and marginal soft tissue mobility. All patients were re-examined after 6 months, and after 1 and 2 years, respectively. A regression analysis was performed to evaluate if alterations, occurring in the position of the periimplant soft tissue margin during the 2 years, could be predicted by various variables recorded at time of the installation of the fixed prosthesis. The descriptive analysis showed a slight decrease in mean probing depth (0.2 mm) and width of masticatory mucosa (0.3 mm) during the follow-up period. Apical displacement of the soft tissue margin mainly took place during the first 6 months of observation. Lingual sites in the mandible showed the most pronounced soft tissue recession, decrease of probing depth, and decrease of width of masticatory mucosa. The statistical analysis revealed that lack of masticatory mucosa and mobility of the periimplant soft tissue at time of bridge installation were poor predictors of soft tissue recession occurring during the 2 years of follow-up, but indicated in greater amount of recession in women than men, in the mandible than in the maxilla, at lingual than at facial sites and with increased initial probing depth. It was suggested that the recession of the periimplant soft tissue margin mainly may be the result of a remodelling of the soft tissue in order to establish "appropriate biological dimensions" of the periimplant soft tissue barrier, i.e., the required dimension of epithelial-connective tissue attachment in relation to the faciolingual thickness of the supracrestal soft tissue.

Cell populations and episodic periodontal attachment loss in humans*

The purpose of the present study was to assess possible associations between episodic probing attachment loss and cell populations in the supracrestal connective tissue in humans. 10 systemically healthy adult patients with untreated advanced periodontitis were monitored during a period of 10 months. At baseline and every month thereafter, probing attachment levels were measured at 6 sites of every tooth using an electronic pressure sensitive probe and flexible stents. Corresponding contralateral sites were identified where 1 site had lost 2 mm or more attachment within the previous month (P), and the other site had not (C). Supracrestal soft tissue biopsies were taken from these sites, processed and cut into 1 micron sections. Cell populations were identified in superficial and deep connective tissue areas by counting fibroblasts, macrophages, plasma cells, mast cells, granulocytes, lymphocytes, endothelial cells and the total number of inflammatory cells. Analysis of variance assessed differences in cell populations between P- and C-sites. There were statistically significantly higher numbers of fibroblasts in the standard areas of C-sites (p less than 0.0001). In P-sites, the numbers of macrophages, plasma cells, mast cells, lymphocytes and total inflammatory cells were significantly higher as compared to C-sites (p = 0.05-0.0001). There were no differences in cell populations between superficial and deep connective tissue areas within P- and C-sites (p greater than 0.2). Clinically assessed episodes of periodontal disease progression may be associated with site-specific shifts in inflammatory cell populations.

Elimination of epithelium from healing postsurgical periodontal wounds by ultra-low temperature. Initial observations.

Prevention of epithelial migration into healing postsurgical periodontal wounds may enhance connective tissue attachment. This study attempted to destroy selectively epithelium on gingival flap surfaces by ultra-low temperature. Sixteen sites in four young adult cats received subcrestal reverse bevel incisions followed by sulcular incisions. Full thickness periodontal flaps were reflected, the remaining supracrestal soft tissue surrounding the teeth was removed, and exposed root surfaces were curetted. Narrow zones measuring about 4 mm along the coronal margins of the flaps were exposed to ultra-low temperature for 5 seconds using a gas expansion cryoprobe cooled to -81 degrees C and placed at the oral gingival aspects of the flaps. Flaps were then repositioned and sutured. Control sites were sham-operated with the cryoprobe kept at room temperature (25 degrees C). Gingival biopsies were taken at 1 hour and at 2, 4, 8 and 12 days following surgery. Microscopically, 1-hour postfreezing and control specimens appeared similar. At 2 and 4 days, large surface areas of corium were denuded of epithelium or were covered by necrotic debris. Mild inflammatory responses were noted within the corium. At 8 days, the epithelium almost completely covered the corium with some initial formation of crevicular epithelium. After 12 days, crevicular epithelium was observed in all tissue sections. No significant morphologic damage to the connective tissue was noted at any time. We, therefore, concluded that low cryodoses can effectively destroy oral gingival epithelium without causing significant morphologic damage to the underlying lamina propria at this level of observation.