Evidence of re-osseointegration after electrolytic cleaning and regenerative therapy of peri-implantitis in humans: a case report with four implants.

OBJECTIVE: To evaluate re-osseointegration after electrolytic cleaning and regenerative therapy of dental implants with peri-implantitis in humans. MATERIAL AND METHODS: Four dental implants that developed peri-implantitis underwent electrolytic cleaning followed by regenerative therapy with guided bone regeneration. All four implants developed recurrent peri-implantitis and were therefore explanted 6 to 13 months later. Radiographic bone level, probing depth, and bleeding on probing were determined at the time of surgery, 6 months later, and before implant retrieval. The peri-implant tissues were histologically and histomorphometrically analyzed. RESULTS: All four implants demonstrated radiographic and histological bone gain, reduced probing depth, and bleeding on probing. Radiographic bone gain was 5.8 mm mesially and 4.8 mm distally for implant #1, 3.3 mm and 2.3 mm for implant #2, 3.1 mm and 0.5 mm for implant #3, and 3.5 mm and 2.8 mm for implant #4. The histometric mean and maximum vertical bone gain for implant #1 to #4 was 1.65 mm and 2.54 mm, 3.04 mm and 3.47 mm, 0.43 mm and 1.27 mm, and 4.16 mm and 5.22 mm, respectively. The percentage of re-osseointegration for implant #1 to #4 was 21.0%, 36.9%, 5.7%, and 39.0%, respectively. In one implant, the newly formed bone was deposited directly onto calculus on the implant surface. CONCLUSIONS: We found that (1) re-osseointegration is possible on a formerly contaminated implant surface and (2) the electrolytic cleaning process seems to be effective enough at sites with calculus residues. CLINICAL RELEVANCE: Since re-osseointegration can be achieved by electrolytic cleaning, this decontamination technique may be considered as a future treatment concept.

Influence of different agents on the preload force of implant abutment screws.

STATEMENT OF PROBLEM: Screw loosening is a common problem in implant dentistry; however, information is sparse on the influence of different fluids on the screw threads. PURPOSE: The purpose of this in vitro study was to investigate the influence of 4 different fluids and agents (saliva, blood, chlorhexidine [CHX] gel, and special sealing silicone) on the preload force of abutment screws. MATERIALS AND METHODS: The test specimens (N=50) consisted of a thread sleeve resembling the implant, an abutment analog, and an abutment screw. The tightening of the screw with a torque wrench was performed in 5 steps (15 Ncm, 20 Ncm, 25 Ncm, 30 Ncm, and 35 Ncm). Each agent was applied in the lumen of the thread sleeve of 10 specimens. Ten dry thread sleeves served as the control. Comparisons between 2 independent groups were performed with the t test or Wilcoxon-Mann-Whitney test, as appropriate. The Bonferroni correction was used for multiple comparisons (α=.05). RESULTS: Preload forces increased linearly with the applied tightening torque for dry implant lumina, as well as for saliva, blood, silicone, and CHX gel in the implant lumina or thread sleeves. In general, none of the tested agents resulted in significantly higher preload forces compared with the dry control. CONCLUSIONS: The agents investigated did not have any lubricant action on implant abutment screws.

How meta-analytic evidence impacts clinical decision making in oral implantology: a Delphi opinion poll.

OBJECTIVES: To investigate the impact of meta-analytic evidence in scientific literature on clinical decision making in the field of oral implantology. METHODS: A Delphi opinion poll was performed at the meeting of the "Next Generation" Committees of the Austrian, German and Swiss Societies for Implantology (ÖGI, DGI and SGI). First, the experts gave their opinion on 20 questions regarding routine implant treatment (uninformed decisions), then they were confronted with up-to-date Level I evidence from scientific literature on these topics and again asked to give their opinion (informed decisions) as well as to rate the available evidence as satisfactory or insufficient. Topics involved surgical issues, such as immediate implant placement, flapless surgery, tilted and short implants and bone substitute materials, as well as opinions on prosthodontic paradigms, such as immediate loading, abutment materials and platform switching. RESULTS: Compared to their uninformed decisions prior to confrontation with recent scientific literature, on average, 37% of experts (range: 15-50%) changed their opinion on the topic. When originally favoring one treatment alternative, less than half were still convinced after review of meta-analytic evidence. Discrepancy between uninformed and informed decisions was significantly associated with insufficient evidence (P = 0.014, 49% change of opinion vs. 26% on topics rated as sufficiently backed with evidence). Agreement regarding strength of evidence could be reached for eight topics (40%), in three issues toward sufficiency and in five issues toward lack of evidence. CONCLUSION: Confrontation with literature results significantly changes clinical decisions of implantologists, particularly in cases of ambiguous or lacking meta-analytic evidence.

Annual failure rates and marginal bone-level changes of immediate compared to conventional loading of dental implants. A systematic review of the literature and meta-analysis.

BACKGROUND: Immediate loading of dental implants appears to be a successful option. Questions still remain whether annual failure rates (AFRs) as well as annual marginal bone-level changes are comparable with conventionally loaded implants. HYPOTHESIS: Immediately loaded implants (≤24 h after implantation) do not show different annual survival rates or peri-implant bone-level changes as compared to conventionally loaded implants (≥3 months after implantation). MATERIAL AND METHODS: An electronic search in the National Library of Medicine and in Cochrane Central Register of Controlled Trials was performed for articles published up to November 2013. Only publications in English were considered. Additionally, the bibliographies of the full-text papers were searched. Primary outcome variable was percentage AFR; secondary outcome variable was annual radiographic bone-level change. RESULTS: Electronic search yielded 154 full-text articles; ten randomized controlled clinical trials were eventually meta-analyzed. Annual failure rates were 2.3% and 3.4% for conventionally and immediately loaded implants, respectively. No difference in implant failure rates was found (RR: 0.82). Regarding marginal bone-level changes, the weighted mean difference (WMD) between immediate and conventional loading amounted to 0.02 mm at 1 year (P > 0.05), to 0.08 mm at 2 years (P > 0.05), -0.10 mm at 3 years (P > 0.05) and -0.3 mm at 5 years (P < 0.05). The total WMD for the combined follow-up was 0.01 mm (P > 0.05). CONCLUSION: No clinically relevant differences regarding annual failure rates or radiographic bone-level changes between conventionally and immediately loaded implants can be found for up to 5 years of follow-up.

Retrospective analysis of augmentation procedures with umbrella screws, a novel tenting technique: a consecutive case series in 279 patients.

OBJECTIVES: The consecutive case series accesses the results and experiences of ridge augmentation using an umbrella screw tenting technique. METHOD AND MATERIALS: In total, 279 patients were treated between 26 May 2015 and 16 June 2021, including horizontal and vertical ridge defects. Sex, age, smoking behavior, jaw, graft material, soft tissue thickness, extent of horizontal/vertical augmentation, resorption rate, and occurrence of early/late exposure were evaluated. Bone gain was determined by resorption at the screw head. Only cases without premature screw removal were evaluated metrically (n = 201). All other augmentations were evaluated according to whether implantation was possible with or without further augmentation (n = 27). A target performance index was calculated, which should enable evidence-based comparability of different augmentation methods in future. RESULTS: In total, 54 wound dehiscences (39 early, 15 late exposures) occurred, which corresponds to 24.08% of the augmented sites; 42 umbrella screws were removed prematurely. In all cases an implantation was possible at the desired position afterwards. Cases with a vertical augmentation component showed a higher prevalence of exposure (early, P = .000; late, P = .024). The extent of the vertical augmentation was only relevant for early exposure (P = .048). Mean bone gain of 4.23 ± 1.69 mm horizontally and 4.11 ± 1.99 mm vertically could be achieved. Regression analysis showed that there was no limit in horizontal/vertical direction. Mean percentage target performance index was 75.90 ± 20.54 for vertical and 82.25 ± 16.67 for horizontal portions. CONCLUSION: The umbrella technique is an effective augmentation method, which can be applied to any defect morphology.

The Impact of Implant Abutment Angle and Height on Peri-implant Tissue Health: Retrospective Analyses from a Randomized Controlled Clinical Trial.

PURPOSE: To examine the influence of abutment emergence angle and abutment height on marginal peri-implant bone stability in patients not considered susceptible to peri-implantitis. Furthermore, it was analyzed whether titanium-base (Ti-base) abutments lead to wider abutment emergence angles compared to one-piece abutments. MATERIALS AND METHODS: A total of 48 abutments (ie, 24 Ti-base and 24 one-piece abutments in 24 patients) were evaluated at abutment installation, after 1 year, and thereafter on a yearly basis for up to 5 years. Clinical and radiographic outcome variables were assessed. RESULTS: With regard to peri-implant marginal bone stability, only moderately negative, albeit significant, correlations were found on the mesial sides of the one-piece abutments after 4 and 5 years for an abutment emergence angle > 30 degrees. No statistically significant negative correlations were found for distances of ≤ 1.5 mm between the restoration margin and the crestal peri-implant bone level for either Ti-base or for one-piece abutments. Furthermore, abutments bonded to Ti-bases were not associated with larger emergence angles than one-piece abutments. CONCLUSIONS: For patients at low risk of developing peri-implantitis, it can be concluded that neither a larger abutment emergence angle (> 30 degrees) nor a distance of ≤ 1.5 mm between the restoration margin and the crestal peri-implant bone level are associated with marginal peri-implant bone loss. Furthermore, abutments bonded to Ti-bases are not associated with wider emergence angles than one-piece abutments.

The impact of implant abutment angle and height on peri-implant tissue health: Retrospective analyses from a randomized, controlled, clinical trial.

PURPOSE: Implant abutment design may influence the predisposition of peri-implant sites to develop peri-implant inflammation, especially peri-implantitis. Therefore, the objectives of the current study were to examine the influence of (1) abutment emergence angle and, (2) abutment height on marginal periimplant bone stability in patients not considered susceptible to peri-implantitis. Furthermore, it was analyzed (3) whether Ti-Base abutments lead to wider abutment emergence angles as compared to onepiece abutments. MATERIALS AND METHODS: 48 abutments (i.e., 24 Ti-base- and 24 one-piece abutments in 24 patients) have been at abutment installation, after one year, and thereafter on a yearly basis for up to five years. Clinical and radiographic outcome variables were assessed. RESULTS: With regard to peri-implant marginal bone stability, (1) only moderately negative, albeit significant, correlations were found on the mesial sides of the one-piece abutments after 4 and 5 years for an abutment emergence angle >30° and no statistically significant negative correlations were found between a distance of less than or equal to versus more than 1.5 mm between the restoration margin and the crestal peri-implant bone level, neither for Ti-Base nor for one-piece abutments. Furthermore, (3) abutments bonded to Ti-bases are not associated with larger emergence angles than one-piece abutments. CONCLUSION: For patients at low risk of developing peri-implantitis it can be concluded, that neither (1) a larger abutment emergence angle (>30°) nor (2) a distance of less than or equal to 1.5 mm between the restoration margin and the crestal peri-implant bone level are per se associated with marginal periimplant bone loss. Furthermore, (3) abutments bonded to Ti-bases are not as such associated with wider emergence angles than one-piece abutments. Int J Prosthodont 2023. doi: 10.11607/ijp.8138.

Influence of Anodizing Stages on the Preload Force of Implant-Abutment Screws and Their Benefits Regarding the Concept of Immediate Implant Placement-An In Vitro Study.

The tightening torque applied to a screw in a provisional restoration immediately after implant placement in a fresh extraction socket is often too low to gain sufficient preload force. Therefore, abutment screw loosening is a common complication. The aim of this study was to investigate whether it is possible to increase the preload force of a given tightening torque by anodizing parts of the implant-abutment complex. In test group 1 (TG1), only the abutment screw was anodized, in four different stages, whereas in test group 2 (TG2), the abutment and the threaded sleeve were anodized in four anodizing stages (TG2a-TG2d). The control group (CG) consisted of non-anodized components. The results were tested for normal distribution, and the components were subsequently parametrically analyzed using a linear model. Both test groups showed higher preload forces compared to the non-anodized control group. The CG obtained an average preload force of 390 N at a tightening torque of 35 Ncm. Comparable values were already obtained at a tightening torque of 20 to 30 Ncm in TG1c/D and TG2b/d. It can be concluded that anodization of abutment screws and components is an effective measure to increase the preload force of the abutment screws by a given tightening torque.

Long-term effects of titanium-base abutments on peri-implant health: A 5-year randomised controlled trial.

PURPOSE: Titanium bases are used frequently in daily practice for bonding to CAD/CAM abutments or crowns. Due to intimate contact between the adhesive gap of the titanium-base abutment and the peri-implant bone, the physical and chemical characteristics of the bonding material, or the gap itself, may affect peri-implant inflammatory reactions. The present study therefore aimed to examine the long-term effects of individualised abutments bonded to titanium bases on peri-implant health. MATERIALS AND METHODS: A total of 24 patients, each with one test and one control abutment, participated in the present prospective, single-blind, randomised controlled clinical trial. The test abutments were CAD/CAM titanium abutments bonded to titanium bases. As the control abutments were individualised, one-piece CAD/CAM titanium abutments were used. Clinical and radiographic parameters were assessed at abutment insertion and then on a yearly basis over the following 5 years. RESULTS: No significant differences in marginal bone level were observed between the titanium-base and one-piece abutments at any of the follow-up time points; however, when intragroup marginal bone levels were compared to the baseline values, significant differences were found at several follow-up time points. Intergroup differences were only found to be significant for pocket depth at the 4- (P = 0.006) and 5-year follow-ups (P = 0.024), favouring titanium-base abutments. CONCLUSIONS: Within the limitations of the present study, it appears that the peri-implant tissues of this specific patient cohort responded to titanium-base abutments in a rather similar manner to one-piece abutments over a 5-year period; however, no definitive conclusions can be drawn due to the low power of the present study.

Inflammatory effects of individualized abutments bonded onto titanium base on peri-implant tissue health: A randomized controlled clinical trial.

BACKGROUND: In implant prosthodontics, computer-assisted design and computer-assisted manufacturing (CAD/CAM) zirconia abutments bonded onto titanium bases are frequently used in prosthetic dentistry. Unpolymerized monomer of the bonding material or the adhesive gap itself may have a negative effect on peri-implant tissue health. However, evidence addressing this problem is not available. PURPOSE: The aim of the current trial was to study inflammatory effects of individualized abutments bonded onto titanium bases. MATERIAL AND METHOD: A total of 24 patients with one test abutment and one control abutment each participated in this prospective, double-blind, randomized controlled clinical trial. Thereby, test abutments were CAD/CAM titanium abutments bonded onto titanium abutments (Ti-Base). As control abutments individualized, one-piece CAD/CAM titanium abutments were used. At abutment installation as well as 6 and 12 months thereafter bone level changes, clinical parameters as well as Il-1ß levels were assessed. RESULTS: Neither for bone level or clinical parameters nor for Il-1ß levels, significant differences between test and control abutments could be found. However, in both groups Il-1ß levels were significantly elevated at both the 6 and 12 months follow-up compared to baseline. CONCLUSION: Within the limits of this RCT, it can be concluded that effects on the inflammatory state of peri-implant tissues do not differ between individualized abutments bonded onto Ti-Bases and individualized one-piece abutments.

Treatment of Periimplantitis with Electrolytic Cleaning versus Mechanical and Electrolytic Cleaning: 18-Month Results from a Randomized Controlled Clinical Trial.

Aim of the study: This RCT assesses patients' 18-month clinical outcomes after the regenerative therapy of periimplantitis lesions using either an electrolytic method (EC) to remove biofilms or a combination of powder spray and an electrolytic method (PEC). Materials and Methods: Twenty-four patients (24 implants) suffering from periimplantitis were randomly treated by EC or PEC followed by augmentation and submerged healing. Probing pocket depth (PPD), Bleeding on Probing (BoP), suppuration, and standardized radiographs were assessed before surgery (T0), 6 months after augmentation (T1), and 6 (T2) and 12 (T3) months after the replacement of the restoration. Results: The mean PPD changed from 5.8 ± 1.6 mm (T0) to 3.1 ± 1.4 mm (T3). While BoP and suppuration at T0 were 100%, BoP decreased at T2 to 36.8% and at T3 to 35.3%. Suppuration was found to be at a level of 10.6% at T2 and 11.8% at T3. The radiologic bone level measured from the implant shoulder to the first visible bone to the implant contact was 4.9 ± 1.9 mm at mesial sites and 4.4 ± 2.2 mm at distal sites at T0 and 1.7 ± 1.7 mm and 1.5 ± 17 mm at T3. Conclusions: Significant radiographic bone fill and the improvement of clinical parameters were demonstrated 18 months after therapy.

Is Complete Re-Osseointegration of an Infected Dental Implant Possible? Histologic Results of a Dog Study: A Short Communication.

Complete reosseointegration after treatment of periimplantitis was never published yet. This short scientific communication reports about results of a randomized controlled preclinical study. An electrolytic approach was compared to a classical modality (ablative, cotton pellets soaked with sodium chloride solution and H2O2. For electrolytic cleaning a complete reosseointegration was achieved in several cases serving as a proof of concept.

Acellular dermal matrix allograft versus autogenous connective tissue grafts for thickening soft tissue and covering multiple gingival recessions: a 5-year preference clinical study.

OBJECTIVES: The present preference clinical trial compared the long-term outcome of acellular dermal matrix allograft (ADMA) versus autogenous connective tissue graft (CTG) in the treatment of gingival recessions. METHOD AND MATERIALS: Thirty-nine consecutive patients with 233 Miller Class I and II recessions were treated by one operator (MS) with coronally advanced flaps and in addition either ADMA or CTG harvested from their palate. Clinical parameters were measured by an independent and masked assessor at baseline, 6 months, and 5 years. RESULTS: Thirty-two patients could be recruited for long-term examination (seven dropouts). At 6 months and 5 years, all clinical parameters showed significant improvements in both groups with slightly better but statistically not significant clinical results for CTGs. At 5 years, the CTG group revealed an additional gain of keratinized mucosa width (t6m-0: CTG 1.88 mm, ADMA 1.04 mm, P = .081; and t5y-0: CTG 3.98 mm, ADMA 3.06 mm, P = .01) compared to 6 months, whereas the mean for ADMAs remained stable (intergroup comparison statistically significant, P = .010). In all other parameters in both groups, slight but not statistically significant relapses were detected. Only one minor postoperative complication at one ADMA-treated site occurred. CONCLUSIONS: Regarding the long-term results, ADMA could be an alternative treatment option to thicken soft tissue and to cover multiple gingival recessions. If the gain of keratinized mucosa width is considered as a main goal, CTG may have a slight advantage over ADMA.

Treatment of Peri-implantitis-Electrolytic Cleaning Versus Mechanical and Electrolytic Cleaning-A Randomized Controlled Clinical Trial-Six-Month Results.

OBJECTIVES: The present randomized clinical trial assesses the six-month outcomes following surgical regenerative therapy of periimplantitis lesions using either an electrolytic method (EC) to remove biofilms or a combination of powder spray and electrolytic method (PEC). MATERIALS AND METHODS: 24 patients with 24 implants suffering from peri-implantitis with any type of bone defect were randomly treated by EC or PEC. Bone defects were augmented with a mixture of natural bone mineral and autogenous bone and left for submerged healing. The distance from implant shoulder to bone was assessed at six defined points at baseline (T0) and after six months at uncovering surgery (T1) by periodontal probe and standardized x-rays. RESULTS: One implant had to be removed at T1 because of reinfection and other obstacles. None of the other implants showed signs of inflammation. Bone gain was 2.71 ± 1.70 mm for EC and 2.81 ± 2.15 mm for PEC. No statistically significant difference between EC and PEC was detected. Significant clinical bone fill was observed for all 24 implants. Complete regeneration of bone was achieved in 12 implants. Defect morphology impacted the amount of regeneration. CONCLUSION: EC needs no further mechanical cleaning by powder spray. Complete re-osseointegration in peri-implantitis cases is possible.

Clinical performance of self-assembling peptide P11 -4 in the treatment of initial proximal carious lesions: A practice-based case series.

AIM: The aim of the present study was to investigate the clinical performance of self-assembling peptide P11 -4 on non-cavitated initial proximal carious lesions 12 months after treatment. METHODS: Twenty-six patients, aged between 18 and 65 years, with 35 carious lesions were included in this practice-based, uncontrolled, prospective case series. The opacity and size of the proximal lesions were evaluated visually at baseline and at day 360 using standardized single-tooth or bite-wing and digital-subtraction radiography. Pairwise evaluation of images was carried out in a randomized and blinded manner with respect to the time point. RESULTS: Twelve months after treatment of the proximal carious lesions, the visual evaluation showed a predominant shift toward regression of the initial lesions. Radiographic assessment yielded regression of the caries in 17 of 28 cases; four of 28 were regarded as unchanged, and seven of 28 lesions showed progression of the carious lesion. Combined assessment of clinical radiographs and digital subtraction radiographs confirmed the radiographic assessment, with 20 of 28 lesions showing total or partial regression, four unchanged, and four progressing. CONCLUSION: Radiographic and digital subtraction analyses suggest that initial proximal carious lesions can regress after treatment with P11 -4, but additional factors might influence the overall treatment outcome.

Self-assembling peptide matrix for treatment of dentin hypersensitivity: A randomized controlled clinical trial.

BACKGROUND: Patient-reported dentin hypersensitivity [DHS] pain is a common finding linked with periodontal disease. This pilot clinical study investigates a novel therapeutic regimen using self-assembling peptide matrix [SAPM] gel (test) compared with use of an 8% arginine and calcium carbonate [ACC] toothpaste (control) for treatment of DHS. METHODS: A total of 50 patients with history of supportive periodontal therapy were enrolled in this prospective, randomized monocentric clinical study, of which 45 (test: n = 22; control: n = 23) fulfilled all the study visits. Test group patients performed ex-office application of SAPM gel over 1 week, while control group patients performed ex-office application of ACC toothpaste over 90 days. DHS was assessed in office by Visual Analog Scale [VAS], and patient's perception of pain relief was evaluated by questionnaire. In support of the clinical data, scanning electron microscopy images were recorded to investigate tubule occlusion of both control and test product. RESULTS: Both SAPM and ACC significantly reduced DHS in patients throughout the study, with the patient questionnaire indicating higher patient satisfaction at the earlier time points for the test group. CONCLUSIONS: Both SAPM gel and ACC toothpaste were successful in providing relief from DHS and showed similar outcomes on VAS and verbal response scale (VRS) throughout the study period of 90 days. The new therapeutic regimen using SAPM resulted in higher patient satisfaction at day 7, as indicated by the patient questionnaire and the higher number of pain-free patients at day 7 and day 90. This is a pilot study describing a novel therapy for DHS.

Effects of Screw Configuration on the Preload Force of Implant-Abutment Screws.

PURPOSE: The aim of this study was to investigate the effects of tightening torque, screw head angle, and thread number on the preload force of abutment screws. MATERIALS AND METHODS: The test specimens consisted of three self-manufactured components (ie, a thread sleeve serving as an implant analog, an abutment analog, and an abutment screw). The abutment screws were fabricated with metric M1.6 external threads. The thread number varied between one and seven threads. The screw head angles were produced in eight varying angles (30 to 180 degrees). A sensor unit simultaneously measured the preload force of the screw and the torsion moment inside the screw shank. The tightening of the screw with the torque wrench was performed in five steps (15 to 35 Ncm). The torque wrench was calibrated before each step. RESULTS: Only the tightening torque and screw head angle affected the resulting preload force of the implant-abutment connection. The thread number had no effect. There was an approximately linear correlation between tightening torque and preload force. CONCLUSION: The tightening torque and screw head angle were the only study parameters that affected the resulting preload force of the abutment screw. The results obtained from this experiment are valid only for a single torque condition. Further investigations are needed that analyze other parameters that affect preload force. Once these parameters are known, it will add value for a strong, but detachable connection between the implant and abutment. Short implants and flat-to-flat connections especially will benefit significantly from this knowledge.

[The use of Emdogain in periodontal and osseous regeneration]. / Die Verwendung von Emdogain in der parodontalen und ossären Regeneration.

The goal of regenerative periodontal therapy is the reconstitution of the lost periodontal structures (i. e. the new formation of root cementum, periodontal ligament and alveolar bone). Results from basic research have pointed to the important role of an enamel matrix protein derivative (EMD) in periodontal wound healing. Histological results from experiments in animals and from human case reports have shown that treatment with EMD promotes periodontal regeneration. Moreover, clinical studies have indicated that treatment with EMD positively influences periodontal wound healing in humans. The goal of the current overview is to present the clinical indications for regenerative therapy with EMD based on the existing evidence.

[External root resorption]. / Externe Wurzelresorption.

Root resorption may be a physiological (resorption of deciduous teeth) or a pathological process (resorption of permanent teeth). In the latter case an external and an internal form of resorption can be distinguished. Root resorption may occur on one tooth or on several teeth within a dentition and it may be caused by trauma, periodontitis, orthodontic treatment, internal bleaching, cysts, tumors, or by stimuli from a necrotic dental pulp. Current knowledge concerning the pathogenesis of root resorption and therapeutic approaches are presented. For cervical resorption, it is assumed that the stimulus for the resorbing cells originates from the bacteria within the gingival sulcus and along the affected root surface. The case presented here was initially diagnosed as chronic periodontitis of medium severity. Scaling and root planing were performed resulting in a significant improvement of the periodontal status. Two years later, following a period of irregular recall visits, the patient presented with large areas of cervical resorption on teeth 36 and 37 which made it impossible to preserve these teeth. After another six months, teeth 34 and 35 showed deep destruction caused by external root resorption, mandating the extraction of these teeth as well. Fourteen months later, external root resorptions were evident on teeth 32 and 33, and at the same time, a recurrence of the chronic periodontitis was noted. Periodontal therapy was performed under a systemic antibiotic regime. It was possible to preserve teeth 32 and 33 through surgical crown lengthening procedures. No additional resorption has been observed ever since.

Treatment of multiple recessions by means of a collagen matrix: a case series.

This case series evaluated the use of a collagen matrix with a coronally advanced flap procedure for the treatment of multiple recession defects. Fifteen patients with a total of 80 recession defects were included. Root coverage was 85% ± 13% at 6 months and 81% ± 22% at 12 months. Complete root coverage was achieved in 60% of the sites after 6 months and in 56% after 12 months. The percentage of sites with thick gingival morphotype increased significantly. The results indicated that the collagen matrix may be a useful alternative to the connective tissue graft in the treatment of multiple recession defects.