Dealing with Evidence in Dental Professional Liability Lawsuits-General Recommendations for Dental Expert Witness Work Using the Example of Germany: A Narrative Review.

Dental treatment can lead to disputes between patients and dentists, which are then brought before the civil courts as medical malpractice cases. The court regularly commissions a dental expert to answer questions of evidence in court. In the majority of cases, the expert is able to answer these questions based on his professional expertise and practical experience. In order to make the assessment comprehensible and credible for the judge and the parties, it can be helpful and reasonable to cite relevant literature references from dental textbooks and specialist journals. In individual cases, it may be necessary to carry out a systematic literature search on specific topics. Based on the situation in Germany, this narrative review makes recommendations of how to perform a literature search and make citations specifically for expert opinions that are generally applicable independent of national jurisdiction.

All-on-4 Concept With Use Of Zygoma Implants for Rehabilitation in the Severely Atrophied Maxilla With a Definitive Immediate Restoration.

This case report of a 45-year-old patient at initial presentation shows an illustration of the limitations of periodontal maintenance therapy and subsequent implant prosthetic therapy. In close consultation with the patient, treatment strategies were adopted to maximize the preservation of prognostically questionable teeth. Eight years later, the patient had a highly atrophied maxilla that could be successfully restored with implants. This was achieved with 2 zygoma implants and 2 anterior conventional implants, which were immediately loaded according to the All-on-4 concept and immediately provided with a definitive prosthetic restoration. The case report demonstrates to the general practitioner that using zygoma implants in such constellations may offer a solution to achieve a fixed, rapid, and financially acceptable prosthetic rehabilitation.

Gemination of an Erupted Mandibular Third Molar: A Short Presentation of an Exceptionally Rare Clinical Occurrence.

Double teeth, like fusions and geminations, are rare disorders of tooth development. In this short case presentation, we describe the unique appearance of a fully erupted mandibular wisdom tooth in a 72-year-old patient whose tooth exhibited gemination. This was possible because tooth 46 had to be removed from the patient at the age of 20 and the missing molar was not replaced. This geminated tooth of 48 had been in function for almost 50 years and finally had to be removed due to a periodontal inflammation. To the best of our knowledge, this is the first case presented of this dental anomaly for a fully erupted lower wisdom tooth.

Unexpected metallic foreign bodies on panoramic scans - a narrative review. / Unerwartete metallene Fremdkörper auf Panoramaschichtaufnahmen ­ eine Übersicht.

BACKGROUND: The digital panoramic radiograph (orthopantomogram, OPG) is the standard radiographic technique for basic diagnostics in dental practice. A correctly taken image provides a good overview of teeth and jaw, whereas radiopaque foreign materials, e. g. metal, can obscure relevant findings. METHODS: A literature review on unexpected metallic foreign bodies in OPG was performed to determine the spectrum of metallic foreign bodies that may cause radiopaque areas on panoramic radiographs in routine clinical use. RESULTS AND CONCLUSION: A total of 37 different unexpected metallic foreign bodies were found. They can be categorized as jewelry, clothing, personal protective equipment, medical devices, iatrogenic foreign bodies, and rare incidental findings. Radiopaque foreign materials in the OPG are often relatively easy to recognize as artifacts because of their location, and they are avoidable in most cases. If unclear, a three-dimensional radiograph was helpful for determining the location. Radiopaque areas caused by foreign bodies can lead to misinterpretation or partial or complete non-evaluability and should therefore be avoided. KEY POINTS: · The OPG is the standard radiograph for dentists, oral surgeons, and oral and maxillofacial surgeons.. · Foreign bodies made of metal can lead to non-evaluability of panoramic radiographs. Based on a review of the literature and exemplary radiographs, this article provides an overview of rare but typical metallic foreign bodies in OPG, thus addressing the problem of the subfield of radiography by making radiologists more familiar with these images.. · The spectrum of unexpected metallic foreign bodies includes unremoved earrings with the typical ghost images on the contralateral side, piercings, hearing aids, acupuncture needles, rare iatrogenic foreign bodies, incidental findings in infants in the nose and external auditory canal, vascular clips after surgical interventions, and ritual subcutaneous foreign materials.. CITATION FORMAT: · Brauer HU, Bartols A, Hellmann D et al. Unexpected metallic foreign bodies on panoramic scans - a narrative review. Fortschr Röntgenstr 2023; 195: 809 - 818.

Lateral Alveolar Ridge Augmentation with Autologous Dentin of Periodontally Compromised Teeth: A Retrospective Study.

Tooth shell technique (TST) using autologous dentine is possible with lateral ridge augmentation while avoiding a donor region. This study aimed to clarify whether the use of periodontally compromised teeth (PCT) leads to similar results compared to non-periodontally compromised teeth (NPCT). In this retrospective study, the dentin matrix of 41 patients (PCT: n = 19 with 29 implants; NPCT: n = 22, with 29 implants) was used for TST. All cases were re-examined. Outcome parameters were biological complications, horizontal hard tissue loss, osseointegration, and the integrity of the buccal lamella. Only in one case in the PCT group, a graft was lost. In three cases, minor complications were identified, including two cases of wound dehiscence and one case of inflammation with suppuration (PCT: n = 1, NPCT: n = 3). All implants, except the one with the severe complication, were osseointegrated and the integrity of the buccal bone lamella was preserved. Mean difference of the resorption of the crestal width and the buccal lamella did not differ statistically between the two groups. TST using PCT showed results comparable to those of NPCT in terms of complications and graft resorption. Processed dentin matrix from PCT can be used and applied with predictable results for bone grafting, utilizing TST.

How do specialist surgeons treat the atrophic tooth gap? A vignette-based study among maxillofacial and oral surgeons.

BACKGROUND: There is little information available regarding the decision-making process of clinicians, especially in the choice of therapy for a severely atrophic tooth gap. The aim of this research was to use case vignettes to determine the influence of possible factors on the decision making of maxillofacial and oral surgeons. METHODS: A total of 250 maxillofacial (MFS) and oral (OS) surgeons in southern Germany were surveyed for atrophic single- or multiple-tooth gap with the help of case vignettes. The influence of different determinants on the therapy decision was investigated. Two case vignettes were designed for this purpose: vignette 1 with determinants "patient age" and "endocarditis prophylaxis" and vignette 2 with determinants "anxiety" and "bisphosphonate therapy". Furthermore, the specialist designation was assessed for both. The options available to achieve a sufficient implant site were "bone split", "bone block", "augmentation with bone substitute material" and "bone resection". Therapy was either recommended or rejected based on principle. RESULTS: A total of 117 participants returned the questionnaire: 68 (58%) were OS and 49 (42%) MFS. "Patient age" and "patient anxiety" were not significantly associated with any therapy decision. However, required "endocarditis prophylaxis" led to significantly higher refusal rates for "bone split", "bone block" and "bone replacement material" and to higher rates of general refusal of a therapy. "Bisphosphonate therapy" was significantly associated with general refusal of therapy, but with no significant correlation with different therapy options. In vignette 1, OS refused therapy significantly more often than MFS, though there was no association with the specialist designation for other therapy modalities. In vignette 2, specialty was not significantly associated with the therapy decision. CONCLUSION: "Patient age" as well as "patient anxiety" appear to have no or little influence on the treatment decision for severely atrophic single- or multiple-tooth gap by specialist surgeons. Surgeons more often refuse treatment for patients with endocarditis prophylaxis and bisphosphonate therapy.

Evaluation of the surgical and prosthetic success of All-on-4 restorations: a retrospective cohort study of provisional vs. definitive immediate restorations.

BACKGROUND: All-on-4 concept allows an immediate restoration, which is frequently a provisional restoration (PR), and will be replaced by a definitive restoration (DR) a few months later. However, this approach involves much higher treatment efforts and costs, compared to a DR immediately after implantation. PRs were mostly incorporated in the introductory phase of the All-on-4 concept in our respective clinics. Today, PRs are only used for referred patients and bimaxillary restorations. The aim of the study was to investigate whether PRs and DRs have comparable success rates. METHODS: A total of 126 patients with 136 All-on-4 restorations supported by 544 implants were included in this retrospective cohort study. The observation period was 1 year. In 42 cases, a PR was placed initially and replaced by a DR 3 months later. In 94 cases, a DR was placed immediately. Biological, technical, and severe (loss of an implant or PR/DR) complications associated with PRs and DRs were compared. The absence of a serious complication was considered a success. RESULTS: A total of 27 patients were affected by 33 complications, 19 biological (2 PR and 17 DR) and 14 technical (6 in PR and 8 in DR) in the first 3 months. Eight patients had ten severe complications (1 PR and 9 DR). Severe complications were all implant losses. Implant survival rate was 98.2% (99.4% PR and 97.6 DR), and restoration survival rate was 94.4% (97.6% PR and 92.6% DR). Six out of the ten implant losses occurred in the posterior maxillae of male patients. After 3 months, ten complications occurred in six patients within 1 year. One of these complications was an implant loss in the posterior maxillae of a male patient. CONCLUSION: PRs and DRs showed comparable complication rates during the observation period. Only in male patients did implant losses occur more frequently in the posterior maxilla.

Decision-Making in Implantology-A Cross-Sectional Vignette-Based Study to Determine Clinical Treatment Routines for the Edentulous Atrophic Mandible.

This cross-sectional study aimed to investigate the influence of possible factors in the patient history on decision making in the therapy for a severely atrophied edentulous mandible. A vignette-based survey among 250 maxillofacial and oral surgeons was conducted. Determinants that could influence the therapy decision were patient age, smoking, fear of surgery, and radiotherapy in the head and neck area (the implant region is not in the direct radiation area). To achieve a suitable implant site, the options offered to the surgeons were bone split, bone block, augmentation with bone substitute material, and bone resection. There also was the option of rejecting any therapy. The response rate was 47%. Patient age, radiotherapy, and fear of surgery did not influence the approval of a therapy. Smoking was associated with a significantly lower endorsement of a treatment. Resection was preferred by a large majority to all other forms of therapy, regardless of the four determinants. Surgeons tend to refrain from bone block transplants in older patients. In summary, it can be said that, of the four determinants, only smoking influenced treatment refusal. Bone resection is the preferred therapy independent of all determinants.

Pre-implantological treatment routines for alveolar ridge atrophy - an investigation among maxillofacial and oral surgeons in southern Germany.

BACKGROUND: It is not well-known which pre-implantological procedures are preferred by maxillofacial (MFS) and oral surgeons (OS) for the narrow atrophic alveolar ridge under practice based conditions and, if different training paths in surgery lead to other pre-implantological techniques being preferred. This study aims to identify which procedures are preferred by the respective specialists in which indication. METHODS: A questionnaire was sent to a total of 300 MFS and OS in southern Germany. The questionnaire examined pre-implantological procedures (bone block, bone grafting material and/or particulate autogenous bone, titanium mesh, bone split, resection) in the edentulous severely atrophic mandible and in the severely atrophic single-tooth gap. Kendall's Tau-b test was used for statistical analyses. RESULTS: One hundred seventeen participants returned the questionnaire. 68 (58%) were OS and 49 (42%) were MFS. In the edentulous mandible, bone substitute material and resection were most preferred by both specialists. Bone blocks were statistically significantly more frequently associated with MFS and bone substitute materials with OS. Bone split was more frequently used in the atrophic single tooth gap than in the edentulous mandible. OS preferred bone blocks in the single tooth gap more often than in the edentulous mandible. MFS and OS preferred resection in the edentulous mandible significantly more frequently than in the single tooth gap. CONCLUSIONS: MFS in general prefer more invasive pre-implantological therapies with the same initial diagnosis than OS, which seems to be attributed to different training paths.

A retrospective assessment of different endodontic treatment protocols.

BACKGROUND: The aim of this study was to assess the clinical impact of non-surgical root canal treatments (NSRCT) performed with different treatment protocols on the probability of tooth survival without untoward events and to identify predictors influencing the outcome. METHODS: During the period from July 1999 to October 2016, 5,858 patients were identified in which 9,967 NSRCTs were performed. The treatments were followed up and divided into three groups. In Group 1 root canal treatment was performed with hand instruments, in Group 2 with multiple file rotary instruments and passive ultrasonic irrigation (PUI), and Group 3 was treated with Reciproc instruments and PUI. Untoward events were defined as orthograde retreatment, apicoectomy or extraction of the tooth after initial treatment. Weibull regression was used to analyse the data. RESULTS: A total of 9,938 cases could be included into the analyses. The results showed 5-years predicted survival rates without untoward events of 73.9% (95% CI [71.7%-76.1%]), 75.1% (95% CI [71.7%-78.0%]) and 78.4% (95% CI [75.1%-81.4%]) for study group 1 (N = 5,580), 2 (N = 1,700) and 3 (N = 2,658), respectively. The differences between Group 1 and 3 were statistically significant (p < 0.006). Higher age of the patient (per year increase) and number of earlier NSRCTs (per unit increase) reduce the survival without untoward events statistically significant (both p < 0.02), while treatment of premolars had a statistically significant lower hazard ratio [0.89 (95% CI [0.79-0.99]; p = 0.030)] compared to treatment of molars and anterior teeth. A higher number of supportive periodontal treatments (per unit increase) improved tooth survival without untoward events highly significant (p < 0.0001). DISCUSSION: More recent endodontic treatment protocols involving reciprocating instruments and PUI appear to be associated with higher tooth survival rates without untoward events compared to hand instruments.

Postoperative discomfort after implant placement according to the All-on-4 concept with or without Zygoma implants: A prospective clinical study.

OBJECTIVES: The purpose of the study was to assess patients' postoperative discomfort after implantations according to the All-on-4 concept with and without using Zygoma implants. MATERIAL AND METHODS: Three treatment groups were formed for this prospective study: All-on-4 rehabilitation in the maxilla (group 1, N = 25), All-on-4 rehabilitation in the maxilla using at least two Zygoma implants (group 2, N = 25), and All-on-4 rehabilitation in the mandible (group 3, N = 20). Principal outcome parameters were postoperative pain (100 mm VAS) and perceived swelling (100 mm VAS). Also, the use of analgesics was documented. RESULTS: The worst postoperative pain of 21.3 (SD 18.9) VAS was observed in group 2, but there was no statistically significant difference between the groups (mixed ANOVA p = .791). The postoperative total intake of painkillers was significantly higher in group 2 than in the other groups (p < .001). On postoperative day 28, the mean pain scores in all groups declined to values below 5 VAS. Postoperative perceived swelling in group 2 was significantly more severe than it was in group 1 and 3 (p < .001). CONCLUSIONS: The use of Zygoma implants in All-on-4 surgical interventions had an essential effect on postoperative swelling, but less so on postoperative pain. The slightly increased, but statistically not significantly different postoperative pain in group 2 was compensated by an overall higher postoperative intake of painkillers compared to the other groups.

Lateral alveolar ridge augmentation with autogenous block grafts fixed at a distance vs resorbable poly-D-L-lactide foil fixed at a distance: 5-year results of a single-blind, randomised controlled trial.

PURPOSE: To report the 5-year outcomes of autogenous bone block grafts fixed at a distance (BBG-D) versus a resorbable poly-D-L-lactide foil fixed at a distance (SonicWeld Rx shell technique [SWST]) randomised controlled trial, for lateral alveolar ridge augmentation. MATERIALS AND METHODS: Thirty patients with a buccopalatal bone width of ≤ 3 mm were randomised into the following treatment groups: BBG-D and SWST. The implant survival, changes in bone morphology visualised in a cone beam computed tomography scan and periodontal parameters were assessed. RESULTS: Thirteen patients in the BBG-D group and seven in the SWST group could be included in the analysis. All implants that osseointegrated initially (BBG-D = 13 and SWST = 7) were functional at the 5-year re-evaluation. The buccopalatal bone width significantly (P < 0.001) decreased over time regardless of the study group. A bone loss of 0.00 mm was observed at the distal implant shoulder in the BBG-D group and 0.29 mm (SD 0.49 mm) in the SWST group (P = 0.04). The mean buccal bone loss was 2.56 mm (SD 3.65 mm) in the BBG-D group and 1.71 mm (SD 4.11 mm) in the SWST group (P = 0.64). The mean probing pocket depth was within sound limits in both groups without significant differences (P > 0.05). Bleeding on probing was low. CONCLUSIONS: Within the limitations of this study, a similar implant survival rate was observed between the BBG-D and SWST techniques during the 5-year follow-up. The buccopalatal bone width decreased over time regardless of the augmentation method used.

Current Knowledge on Correlations Between Highly Prevalent Dental Conditions and Chronic Diseases: An Umbrella Review.

INTRODUCTION: Studies have investigated the relationships between chronic systemic and dental conditions, but it remains unclear how such knowledge can be used in clinical practice. In this article, we provide an overview of existing systematic reviews, identifying and evaluating the most frequently reported dental-chronic disease correlations and common risk factors. METHODS: We conducted a systematic review of existing systematic reviews (umbrella review) published between 1995 and 2017 and indexed in 4 databases. We focused on the 3 most prevalent dental conditions and 10 chronic systemic diseases with the highest burden of disease in Germany. Two independent reviewers assessed all articles for eligibility and methodologic quality using the AMSTAR criteria and extracted data from the included studies. RESULTS: Of the initially identified 1,249 systematic reviews, 32 were included for qualitative synthesis. The dental condition with most frequently observed correlations to chronic systemic diseases was periodontitis. The chronic systemic disease with the most frequently observed correlations with a dental condition was type 2 diabetes mellitus (T2DM). Most dental-chronic disease correlations were found between periodontitis and T2DM and periodontitis and cardiovascular disease. Frequently reported common risk factors were smoking, age, sex, and overweight. Using the AMSTAR criteria, 2 studies were assessed as low quality, 26 studies as moderate quality, and 4 studies as high quality. CONCLUSION: The quality of included systematic reviews was heterogeneous. The most frequently reported correlations were found for periodontitis with T2DM and for periodontitis with cardiovascular disease. However, the strength of evidence for these and other disease correlations is limited, and the evidence to assess the causality of these disease correlations remains unclear. Future research should focus on the causality of disease links in order to provide more decisive evidence with respect to the design of intersectoral care processes.

Assessment of Different Root Canal Preparation Techniques with Rotary Nickel-Titanium Instruments by Novice Students.

This study investigated which preparation strategy for root canals leads to the best technical preparation quality, and moreover, which is perceived to be performed best by novice students. Sixty-four students were recruited to prepare one simulated root canal with each of the following: FlexMaster files (F), Mtwo files (M), and Reciproc files (R). After preparation, the students assessed the different instrument systems through a questionnaire. The technical quality of the root canal preparations was evaluated by the centering ratio of the preparation. A total of 186 prepared root canals were submitted for evaluation. With R, significantly better centered preparations were achieved when compared to M and F (p < 0.001). The students evaluated R faster than M and F, and evaluated F significantly (p < 0.05) slower than R and M. M was rated as the easiest system to learn and to handle, as well as the best at reaching the working length; therefore, it was evaluated as the overall favorite of the students. A difference was found between the students' perceptions and their achieved technical quality of root canal preparations.

Shaping ability of four root canal instrumentation systems in simulated 3D-printed root canal models.

INTRODUCTION: The aim of this study was to compare the shaping ability of four root canal preparation systems in newly developed 3D-printed root canal models. MATERIALS AND METHODS: For this study, 1080 3D-printed acrylic resin blocks with nine different root canal configurations were produced. They were prepared with Reciproc R25 (#25), F6 SkyTaper (#25 and #30) F360 (#25 and #35) and One Shape (#25) (N = 30 per system). Pre- and post-instrumentation images were superimposed for evaluation of the centering ratio of the different systems. Ledges, instrument fractures and preparation times were also recorded. Analysis of variance (ANOVA) and post-hoc Tukey tests were conducted, comparing the mean canal centering ratios and the mean preparation times. RESULTS: There were significant differences between all systems regarding the centering ratios in the different root canal configurations (ANOVA p < 0.001). The root canal configuration had considerable effect on the centering ratio of the instruments. The best overall mean centering ratios were achieved with F6 SkyTaper #25 instruments especially in canal configurations with big curvature angles and radii, while F360 #35 was least centered especially in canals with small curvature angles and radii. Most ledges occurred with OneShape, while it was the significantly (p < 0.001) fastest preparation system (86.7 s (SD 13.53)) and Reciproc the significantly (p < 0.001) slowest (103.0 s (SD 20.67)). CONCLUSION: 3D-printed root canals are suitable to produce challenging canal configurations and to investigate the limitations of root canal instruments. We found that all instruments caused canal transportations. However, F6 SkyTaper #25 files had better overall centering ratios than the other instruments. In canal configurations with small curvature radii, the centering ratio of some instruments is low and the probability for ledges is increased.

Lateral alveolar ridge augmentation with autogenous block grafts fixed at a distance versus resorbable Poly-D-L-Lactide foil fixed at a distance: A single-blind, randomized, controlled trial.

OBJECTIVES: The aim of this study was to compare bone block grafts fixed at a distance (BBG-D) with the SonicWeld Rx shell technique (Poly-D-L-Lactide foil fixed at a distance, augmented with autogenous and deproteinized bovine bone particles (SWST)) for lateral alveolar ridge augmentation. METHODS: In this single-blinded, randomized, controlled trial, 30 patients with a bucco-palatal bone width of ≤3 mm were randomized into the treatment groups: "BBG-D" and "SWST". Bone width was measured with cone beam computed tomography (CBCT). One implant was placed at each grafted site. Frequencies of complications, bone gain and bone resorption in the CBCT were assessed as outcomes. RESULTS: Fifteen sites were augmented in each treatment group. One graft (7%) in the BBG-D group and five (33%) in the SWST group were lost (p = 0.17). In the SWST group, two implants (20%) were lost and none in the BBG-D group (p = 0.18). The rate of pooled severe complications (loss of graft and/or implant) was different (p = 0.035). Five (33%) wound dehiscences happened in the SWST group and none in the BBG-D group (p = 0.042). Seven (47%) nonsevere complications (wound dehiscence, inflammation, transient nerve injury) happened in the SWST group and one (7%) in the BBG-D group (p = 0.035). At the one-year evaluation, there were no significant differences in bone loss at the mesial, distal or buccal implant shoulder between treatment groups. CONCLUSIONS: Within the limitations of this study, the BBG-D method remains the gold standard for lateral alveolar ridge augmentation compared to the shell technique because of the lower complication rates.

The accuracy of the auto-stop function of different endodontic devices in detecting the apical constriction.

BACKGROUND: Electronic apex locators (EALs) are modern devices used to determine the working length during root canal preparation. The newest endodontic motors provide an integrated EAL with auto-stop function to prevent instrumentation beyond the predefined working length during rotary root canal preparation. The aim of this study was to compare the accuracy of the auto-stop function of the VDW.Gold RECIPROC motor (VDW, Munich, Germany), the EndoPilot motor (Schlumbohm, Brokstedt, Germany) and the manual measurement with Raypex 6 (VDW, Munich, Germany) to detect the apical constriction (AC). METHODS: Ninety human teeth were chosen and randomly assigned to three experimental groups (30 teeth each): VDW.Gold RECIPROC motor continuous measuring (RCM), EndoPilot continuous measuring (ECM) and Raypex 6 manual measuring (RMM). When the measurement file reached the AC, the file was fixed in the tooth. The tooth was embedded in acrylic resin and the root tip was exposed, so that the histologic structure of the root canal and the file tip was visible for microscopic analysis. Afterwards, the distance of the file tip to the AC (DAC) was automatically computed with a specially developed software tool. RESULTS: The mean DAC were -13.18 µm (SD 88.46 µm) for RMM, -22.70 µm (SD 91.57 µm) for RCM and 18.74 µm (SD 88.11 µm) for ECM. The differences were not statistically significant (P = 0.181). The rates for instrumentation beyond the AC were not statistically different (Chi2 = 4.753, p = 0.096). CONCLUSIONS: All measurement methods showed a high accuracy in detecting the AC. The auto-stop function of these endodontic motors is a reliable addition to the endodontic armamentarium.

The ability of Reciproc instruments to reach full working length without glide path preparation: a clinical retrospective study.

BACKGROUND: Reciproc instruments are the only contemporary root canal instruments where glide path preparation is no longer strictly demanded by the manufacturer. As the complete preparation of root canals is associated with success in endodontic treatment we wanted to assess the ability and find predictors for Reciproc instruments to reach full working length (RFWL) in root canals of maxillary molars in primary root canal treatment (1°RCTx) and retreatment (2°RCTx) cases. METHODS: This retrospective study evaluated 255 endodontic treatment cases of maxillary molars. 180 were 1°RCTx and 75 2°RCTx. All root canals were prepared with Reciproc instruments. The groups were compared and in a binary logistic regression model predictors for RFWL were evaluated. RESULTS: A total of 926 root canals were treated with Reciproc without glide path preparation. This was possible in 885 canals (95.6%). In 1°RCTx cases 625 of 649 (96.3%) canals were RFWL and in 2°RCTx cases 260 of 277 (93.9%). In second and third mesiobuccal canals (MB2/3) 90 out of 101 (89.1%) were RFWL with Reciproc in 1°RCTx and in the 2°RCTx treatment group 49 out of 51 cases (96.1%). In mesio-buccal (MB1) canals "2°RCTx" was identified as negative predictor for RFWL (OR 0.24 (CI [0.08-0.77])). In MB2/3 canals full working length was reached less often (OR 0.04 (CI [0.01-0.31])) if the tooth was constricted and more often if MB2/3 and MB1 canals were convergent (OR 4.60 (CI [1.07-19.61])). DISCUSSION: Using Reciproc instruments, the vast majority of root canals in primary treatment and retreatment cases can be prepared without glide path preparation.

First Evidence for Regeneration of the Periodontium to Mineral Trioxide Aggregate in Human Teeth.

INTRODUCTION: The aim of this study was to elucidate whether the use of mineral trioxide aggregate (MTA) in endodontic therapy in human teeth leads to the same regeneration of the apical tissues as observed in animals. METHODS: Four human teeth were identified in a policlinic that had been treated endodontically with MTA and had to be extracted for other reasons than just endodontic failure. All teeth were processed for histologic and one for immunohistochemical analyses to analyze the histologic response of the periapical structure to the former treatment with MTA. RESULTS: All identified teeth showed clinical and radiographic signs of healing at the time of extraction. In the histologic evaluation, all teeth showed a layer of cementlike tissues at least on the MTA surface. Further double immunofluorescence analyses for collagen type I and type III revealed protein expression and colocalization of the 2 proteins, implicating formation of periodontal ligamentlike tissue, presumably fibers. CONCLUSIONS: Histologic healing of the human periodontium to MTA corresponds to the healing pattern shown in animal studies. Cementlike tissues were formed on the surface of MTA, which proves regeneration of the periodontal ligament.

Cement-associated peri-implant mucositis. A 1-year follow-up after excess cement removal on the peri-implant tissue of dental implants.

BACKGROUND: Methacrylate-based cements seem to promote peri-implant tissue inflammation even in the absence of excess cement. PURPOSE: The present study deals with the question of whether the removal of methacrylate cement from the peri-implant sulcus will lead to peri-implant tissues free of inflammation on a 1-year follow-up basis. MATERIAL AND METHODS: Implant supported suprastructures that had been in the mouth for at least 3.5 years either cemented with methacrylate (premier implant cement [PIC]) or zinc eugenol (temp bond [TB]) cement were compared. All superstructures in 33 patients with a total of 61 implants (35 with PIC and 26 with TB) were removed and excess cement, bleeding on probing (BOP), suppurationen and probing depth were documented. Excess cement found was removed, and in all cases the suprastructure was recemented with TB. Patients were followed up after 4 weeks (F1) and 1 year (F2). RESULTS: Excess cement was found around 60% of the implants with PIC. No excess cement was found around implants with TB. At the time of revision therapy, BOP was found around 100% of the implants with PIC and excess cement (PIC+), 93% around implants with PIC but no excess cement (PIC-), and around 42% of the TB-cemented implants (Chi-squared P < .01). Suppuration was observed in 86% of the PIC+ implants, in 14% of the PIC- implants and in 0% of the TB implants (Chi-squared P < .01). At the time of both F1 and F2, the inflammation parameters, that is BOP and suppuration, on implant level were significantly reduced in the PIC+ cases (McNemar's test P < .01). For PIC-, BOP was significantly reduced at both points in time (P < .05). For TB no differences were found. Probing depth at F2 had significantly decreased in all groups (t test P < .05). CONCLUSION: The removal of excess cement and recementation with TB had an anti-inflammatory effect on the peri-implant tissues after 1 year.