Publications by authors named "Sigmar Schnutenhaus"

21 Publications

  • Page 1 of 1

A virtual clinical feasibility study for the indication of one-piece ceramic implants in the anterior maxilla.

Int J Comput Dent 2021 Sep;24(3):263-273

Aim: One-piece ceramic implants (O-PCIs) have proven to be clinically useful, with high survival rates. The biocompatibility and bio-inert characteristics of ceramics in addition to the fact that minimal plaque deposits occur on these materials provide esthetic advantages and justification for their use in the anterior maxilla. The objective of the present study was to investigate the suitability of O-PCI use in the anterior maxilla.

Materials And Methods: The data of patients who had received conventional two-piece titanium implants were analyzed. Virtual planning was performed to determine whether O-PCIs could have been used. Three groups were formed: single-tooth gap (group A); multiple-tooth gap treated with two implants (group B); and complex treatments with at least three implants (group C). In addition to assessing the feasibility of O-PCIs, their usefulness as well as additional procedures such as augmentation and a change in the implant quantity or position were evaluated. Values of the location of the virtual cementation line were summarized for all cases.

Results: Without additional procedures, O-PCIs could be used in 97.9% of group A, 77.3% of group B, and 59.1% of group C. For group B, 18.2% of the cases could have been managed with additional augmentation. For the complex cases (group C), 18.2% of the patients would have been treatable if the planning had been altered, augmentation had been performed or implants with an inclined abutment had been available. The mean value of the lowest point of the cementation line was 2.9 mm (standard deviation 1.23; 0.0 to 7.2 mm).

Conclusion: O-PCIs can be used in the anterior maxilla with planning. The esthetic advantages of ceramics can be leveraged for this part of the mouth, especially for single-tooth gaps.
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September 2021

Influence of the Gingival Condition on the Performance of Different Gingival Displacement Methods-A Randomized Clinical Study.

J Clin Med 2021 Jun 22;10(13). Epub 2021 Jun 22.

Department of Prosthetic Dentistry, Center of Dentistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.

This randomized clinical study examined the influence of the gingival condition-healthy versus mild inflammation-on sulcus representation and possible gingival recession for two gingival displacement procedures prior to conventional impression making. The interventions double cord technique or a kaolin paste containing aluminum chloride were applied to 40 probands. The opposite quadrant served as intrapersonal reference (split-mouth design). Precision impressions were then made. Extraoral digitization of the plaster models resulting from the reference impression prior to gingival displacement, the intervention impression and control impressions were the basis for the computer-aided three-dimensional analysis. After six months, a mild artificial gingivitis was induced, and the contralateral quadrant (cross-over design) was examined for the intervention. The gingivitis deteriorated the sulcus representation for the double cord technique group but did not affect the paste technique group. The gingival condition had no influence on the marginal gingiva height changes. The minor extent of those changes, which were measured up to six months after intervention at the palatal study site, were not considered to be in the clinically relevant range for gingival recession. For healthy gingiva, the cord technique showed superior sulcus representation compared to the paste technique. This advantage was lost to a great extent under the conditions of mild gingivitis.
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http://dx.doi.org/10.3390/jcm10132747DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8268533PMC
June 2021

Factors Influencing the Accuracy of Freehand Implant Placement: A Prospective Clinical Study.

Dent J (Basel) 2021 May 10;9(5). Epub 2021 May 10.

Department of Prosthetic Dentistry, Center of Dentistry, Ulm University, 89081 Ulm, Germany.

(1) Background: The objective of implant prosthetic restoration is to ensure the best possible rehabilitation of function and esthetics. Optimal positioning of the implant with regard to the bone availability, surrounding soft tissue, and prosthetic sustainability should be strived for during implant placement. The factors influencing freehand implant placement and the accuracy achieved with this procedure are investigated in this prospective clinical study. (2) Methods: Implants were placed in the single-tooth edentulous sites of the premolar and molar areas in 52 patients. Three-dimensional (3D)-planning was performed virtually prior to the freehand implant operation, and the desired position of the implant was provided to the surgeon. (3) Results: The deviations between the planned and the actually achieved position with freehand implant placement showed the following mean values and standard deviations: angle 8.7 ± 4.8°, 3D deviation at the implant shoulder 1.62 ± 0.87 mm, mesiodistal deviation 0.87 ± 0.75 mm, buccolingual deviation 0.70 ± 0.66 mm, and apiocoronal deviation 0.95 ± 0.61 mm. The type of jaw had a significant influence on accuracy. Major deviations were observed in the lower jaw. Furthermore, the timing of implant placement influenced the mesiodistal deviation and angular deviation; (4) Conclusions: Freehand implant placement demonstrated a higher level of deviation between the planned and actually achieved implant positions. In particular, the ranges showed a large spread. From a prosthetic point of view, there may be complications during the restoration of the prosthetic crown if the implant exit point is not optimally located or if the implants show a high angular deviation.
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http://dx.doi.org/10.3390/dj9050054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151810PMC
May 2021

Accuracy of Computer-Assisted Dynamic Navigation in Implant Placement with a Fully Digital Approach: A Prospective Clinical Trial.

J Clin Med 2021 Apr 21;10(9). Epub 2021 Apr 21.

Centre for Dentistry, Dr Schnutenhaus Community Health Centre (CHC) GmbH, 78247 Hilzingen, Germany.

Background: This prospective clinical study aimed to investigate a possible deviation between the digitally planned implant position and the position achieved using dynamic navigation. The aim of the study was to establish clinical effectiveness and precision of implantation using dynamic navigation.

Methods: Twenty consecutive patients received an implant (iSy-Implantat, Camlog, Wimsheim, Germany). One screw implant was placed in one jaw with remaining dentition of at least six teeth. The workflow was fully digital. Digital implant planning was conducted using cone-beam computed tomography (CBCT) and an intraoral scan of the actual condition. Twenty implants were subsequently placed using a dynamic computer-assisted procedure. The clinical situation of the implant position was recorded using an intraoral scan. Using these data, models were produced via 3D printing, and CBCTs of these models were made using laboratory analogs. Deviations of the achieved implant position from the planned position were determined using evaluation software.

Results: The evaluation of 20 implants resulted in a mean angle deviation of 2.7° (95% CI 2.2-3.3°). The 3D deviation at the implant shoulder was 1.83 mm (95% CI 1.34-2.33 mm). No significant differences were found for any of the parameters between the implantation in the upper or lower jaw and an open or flapless procedure (-value < 0.05).

Conclusion: The clinical trial showed that sufficiently precise implantation was possible with the dynamic navigation system used here. Dynamic navigation can improve the quality of implant positioning. In particular, the procedure allows safe positioning of the implants in minimally invasive procedures, which usually cannot be performed freehand in this form. A clinical benefit and effectiveness can be determined from the results.
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http://dx.doi.org/10.3390/jcm10091808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8122675PMC
April 2021

Does the macro design of an implant affect the accuracy of template-guided implantation? A prospective clinical study.

Int J Implant Dent 2021 04 26;7(1):42. Epub 2021 Apr 26.

Clinic for Dental Prosthetics, Center for Dental, Oral and Maxillofacial, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.

Background: An implant prosthesis aims to ensure the best possible rehabilitation of function and esthetics following tooth loss. Template-guided insertion is used to achieve an optimal position of the implant with regard to prosthetic restorability, bone availability, and condition of the surrounding soft tissues. The accuracy of template-guided implant placement is subject to various influencing factors. The clinically achievable accuracy depending on the macro design of the implant body was investigated in this prospective clinical study.

Material And Methods: In this prospective clinical study, 20 implants were placed in 20 patients. The implant had a pronounced conical outer geometry (Conelog ProgressiveLine, Camlog Wimsheim, Germany). Data from a study using an implant with a distinct cylindrical outer geometry were used as a comparison group (Conelog ScrewLine, Camlog, Wimsheim, Germany). The clinically achieved implant position was compared with the planned position.

Results: The evaluation of the two-dimensional deviations in direction resulted in the following mean values (standard deviation) at the shoulder: 0.42 mm (0.33) in the buccolingual direction, 0.27 mm (0.25) in the mesiodistal direction, and 0.68 mm (0.55) in the apicocoronal direction. The mean angular deviation was 4.1° (2.3). The three-dimensional (3D) deviation was 0.94 mm (0.53) at the shoulder and 1.36 mm (0.62) at the apex of the implant. Significant differences between implants with different macro designs were found in the apicocoronal direction. In connection to this, a significant 3D deviation was found at the implant shoulder.

Conclusions: Significant differences in height were found between the groups. The study had shown that the macro design of an implant has no influence on accuracy in all other directions. Overall, the implants showed a high level of accuracy and a low variation in values. The values were in the range determined by the template-guided insertion system in numerous other investigations. This provides good predictability of prosthetic rehabilitation.

Trial Registration: German Register for Clinical Studies (DRKS-ID: DRKS000018939 ). Date of registration: November 11, 2019.
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http://dx.doi.org/10.1186/s40729-021-00320-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071785PMC
April 2021

Accuracy of Computer-Assisted Dynamic Navigation as a Function of Different Intraoral Reference Systems: An In Vitro Study.

Int J Environ Res Public Health 2021 03 21;18(6). Epub 2021 Mar 21.

Department for Dentistry, Clinic for Prosthodontics, Ulm University, 89081 Ulm, Germany.

The aim of this in vitro study was to determine whether the process chain influences the accuracy of a computer-assisted dynamic navigation procedure. Four different data integration workflows using cone-beam computed tomography (CBCT), conventional impressions, and intraoral digitization with and without reference markers were analyzed. Digital implant planning was conducted using data from the CBCT scans and 3D data of the oral models. The restoration of the free end of the lower jaw was simulated. Fifteen models were each implanted with two new teeth for each process chain. The models were then scanned with scan bodies screwed onto the implants. The deviations between the planned and achieved implant positions were determined. The evaluation of all 120 implants resulted in a mean angular deviation of 2.88 ± 2.03°. The mean 3D deviation at the implant shoulder was 1.53 ± 0.70 mm. No significant differences were found between the implant regions. In contrast, the workflow showed significant differences in various parameters. The position of the reference marker affected the accuracy of the implant position. The in vitro examination showed that precise implantation is possible with the dynamic navigation system used in this study. The results are of the same order of magnitude that can be achieved using static navigation methods. Clinical studies are yet to confirm the results of this study.
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http://dx.doi.org/10.3390/ijerph18063244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8003934PMC
March 2021

Effects of abutment height and type of cements on bond strength of monolithic zirconia single crowns luted to one-piece zirconia implants.

Int J Prosthodont 2021 Mar 18. Epub 2021 Mar 18.

Purpose: To test the bond strength of one-piece zirconia implants with either standard or reduced height using different luting agents and pretreatments of the ceramic crowns' inner surfaces.

Materials And Methods: Twenty monolithic CAD/CAM-fabricated zirconia single crowns were cemented onto 10 one-piece zirconia implants with either 5-mm or 4-mm abutment height (Z-Look3 Evo SLM, Z-Systems) using 13 different luting agents. After water storage, the crowns were removed using a specially developed test fixture in a universal testing machine (Z010, Zwick/Roell). The maximum force was recorded (N), and the force per area was calculated (MPa). The statistical evaluation was performed using univariate analysis of variance (SPSS version 25.0, IBM).

Results: A mean of 4.19 MPa (SD 2.90) at 5 mm and 3.89 MPa (SD 2.85) at 4 mm was obtained for all luting agents. The highest values were achieved for a resinmodified glass-ionomer cement, with 12.37 MPa (4 mm)/12.00 MPa (5mm). The lowest values were shown for a long-term temporary material, with 0.73 MPa (4 mm)/1.07 MPa (5 mm). Only a polycarboxylate cement (P < .001) and a glass-ionomer cement (P = .006) showed statistically significant differences, in favor of the reduced abutment height. The latter did not significantly reduce bond strength for any of the materials examined.

Conclusion: Implants with a reduced abutment height are clinically suitable. Pretreatment of the crowns' inner surfaces with ceramic primer showed to be advantageous.
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http://dx.doi.org/10.11607/ijp.7110DOI Listing
March 2021

Accuracy of Dynamic Computer-Assisted Implant Placement: A Systematic Review and Meta-Analysis of Clinical and In Vitro Studies.

J Clin Med 2021 Feb 11;10(4). Epub 2021 Feb 11.

Center of Dental, Oral and Maxillofacial Medicine, Clinic for Dental Prosthetics, Ulm University, 89081 Ulm, Germany.

The aim of this systematic review and meta-analysis is to analyze the accuracy of implant placement using computer-assisted dynamic navigation procedures. An electronic literature search was carried out, supplemented by a manual search. The literature search was completed in June 2020. The results of in vitro and clinical studies were recorded separately from each other. For inclusion in the review, the studies had to examine at least the prosthetically relevant parameters for angle deviation, as well as global deviation or lateral deviation at the platform of the implant. Sixteen of 320 articles were included in the investigation: nine in vitro and seven clinical studies. The meta-analysis showed values of 4.1° for the clinical studies (95% CI, 3.12-5.10) and 3.7° for the in vitro studies (95% CI, 2.31-5.10) in terms of the angle deviation. The global deviation at the implant apex of the implant was 1.00 mm for the clinical studies (95% CI, 0.83-1.16) and 0.91 mm for the in vitro studies (95% CI, 0.60-1.12). These values indicate no significant difference between the clinical and in vitro studies. The results of this systematic review show a clinical accuracy of dynamic computer-assisted navigation that is comparable to that of static navigation. However, the dynamic navigation systems show a great heterogeneity that must be taken into account. Moreover, currently there are few clinical data available. Therefore, further investigations into the practicability of dynamic navigation seem necessary.
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http://dx.doi.org/10.3390/jcm10040704DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7916851PMC
February 2021

Prosthetic rehabilitation of a patient with cleidocranial dysplasia using dental implants-a clinical report.

Int J Implant Dent 2021 01 22;7(1). Epub 2021 Jan 22.

Department of Prosthetic Dentistry, Center of Dentistry, Ulm University, Ulm, Germany.

Adult patients with oral manifestations of untreated syndromic malformations usually exhibit a high degree of suffering. In this clinical report, we describe the implant-supported prosthetic treatment of a patient with cleidocranial dysplasia, a rare autosomal-dominant inherited malformation syndrome. Therapy for oral manifestations of cleidocranial dysplasia should be started in early childhood; however, the 26-year-old patient in the present study had not undergone orthodontic therapy in childhood. The treatment measures performed prior to this study were limited to the removal of several permanent teeth. Surgical pretreatment, placement of six implants each in the maxilla and mandible, and prosthetic restoration are described. The implantation was guided using a three-dimensional template. Long-term immediate temporary restoration and immediate loading of the implants were performed. The definitive prosthetic restoration was completed using fixed, acrylic resin-veneered screw-retained fixed dental prostheses. The clinical and radiological parameters observed in this case suggest that surgical and prosthetic procedure concepts from implantology can be adopted for patients with CCD.
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http://dx.doi.org/10.1186/s40729-020-00287-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820043PMC
January 2021

Associations among Primary Stability, Histomorphometric Findings, and Bone Density: A Prospective Randomized Study after Alveolar Ridge Preservation with a Collagen Cone.

Dent J (Basel) 2020 Oct 2;8(4). Epub 2020 Oct 2.

Center of Dentistry, Department of Prosthetic Dentistry, Ulm University, 89081 Ulm, Germany.

Background: The objective of this investigation was to examine whether determination of bone density (BD) with a cone beam computed tomography (CBCT) scan could help predict the primary stability (PS) of the implants and to investigate whether associations between the histomorphometric findings and the CBCT scan could be observed.

Materials And Methods: In this randomized clinical study, the efficacy of alveolar ridge preservation (ARP) with a combination of a collagen cone and a collagen membrane procedure after tooth extraction was investigated. CBCT scans were obtained after a healing period of 8 (±1) weeks. Subsequently, the CBCT scans were evaluated in terms of BD at different heights of the former socket. Eleven (±1) weeks after tooth extraction, implant placement was performed and PS was measured with resonance frequency analysis. Potential associations among the radiologically measured BD, the histomorphometric results, and the PS were analyzed.

Results: No direct association was observed between the radiologically determined BD and the histomorphometric findings. No significant associations could be found between the BD and the PS.

Conclusion: No significant associations were observed among the BD determined by the CBCT, the histomorphometric findings, and the PS.
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http://dx.doi.org/10.3390/dj8040112DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7712570PMC
October 2020

Alveolar ridge preservation and primary stability as influencing factors on the transfer accuracy of static guided implant placement: a prospective clinical trial.

BMC Oral Health 2020 06 29;20(1):178. Epub 2020 Jun 29.

Department for Dentistry, Clinic for Prosthodontics, Universität Ulm, Department für Zahnheilkunde, Klinik für Zahnärztliche Prothetik [Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.

Background: The aim of this prospective clinical study was to investigate differences between virtually planned and clinically achieved implant positions in completely template-guided implant placements as a function of the tooth area, the use of alveolar ridge preservation, the implant length and diameter, and the primary implant stability.

Methods: The accuracy of 48 implants was analyzed. The implants were placed in a completely template-guided manner. The data of the planned implant positions were superimposed on the actual clinical implant positions, followed by measurements of the 3D deviations in terms of the coronal (dc) and apical distance (da), height (h), angulation (ang), and statistical analysis.

Results: The mean dc was 0.7 mm (SD: 0.3), the mean da was 1.4 mm (SD: 0.6), the mean h was 0.3 mm (SD: 0.3), and the mean ang was 4.1° (SD: 2.1). The tooth area and the use of alveolar ridge preservation had no significant effect on the results in terms of the implant positions. The implant length had a significant influence on da (p = 0.02). The implant diameter had a significant influence on ang (p = 0.04), and the primary stability had a significant influence on h (p = 0.02).

Conclusion: Template-guided implant placement offers a high degree of accuracy independent of the tooth area, the use of measures for alveolar ridge preservation or the implant configuration. A clinical benefit is therefore present, especially from a prosthetic point of view.

Trial Registration: German Clinical Trial Register and the International Clinical Trials Registry Platform of the WHO: DRKS00005978 ; date of registration: 11/09/2015.
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http://dx.doi.org/10.1186/s12903-020-01155-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7322921PMC
June 2020

Alveolar ridge preservation with a collagen cone: Histological, histochemical, and immunohistochemical results of a randomized controlled clinical trial.

Clin Exp Dent Res 2020 06 22;6(3):345-355. Epub 2020 Jan 22.

Department of Orthodontics, Oral Biology Laboratory, University of Bonn, Bonn, Germany.

Objectives: The objective of the present study was to examine the influence of a combination material of a collagen cone and a collagen membrane on the healing process of extraction sockets with regard to histological, histochemical, and immunohistochemical parameters.

Materials And Methods: In a prospective randomized clinical study, 10 patients (test group) received a collagen combination material after tooth removal. The extraction sockets of 10 other patients (control group) were left to heal without further intervention. Eleven ±1 weeks after tooth extraction, histological biopsies were performed in both groups at the time of implant placement. Subsequently, the biopsies were evaluated semiquantitatively in terms of histological, histochemical, and immunohistochemical parameters for the identification of factors of bone metabolism and vascularization.

Results: No significant difference between test and control group were found for any parameter. According to the descriptive data, the use of a collagen combination material seems to result in slightly higher values of the osteogenic Runt-related transcription factor 2 (Runx2) and vascularization.

Conclusion: The histological, histochemical, and immunohistochemical analysis of ARP with a collagen cone combined with a collagen membrane showed no significant differences in terms of bone metabolism and vascularization.
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http://dx.doi.org/10.1002/cre2.279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301397PMC
June 2020

Reproducibility of CBCT image analysis: a clinical study on intrapersonal and interpersonal errors in bone structure determination.

Oral Radiol 2019 05 27;35(2):152-158. Epub 2018 Jul 27.

Department of Prosthetic Dentistry, Center of Dentistry, Ulm University, Albert-Einstein-Allee 1, 89081, Ulm, Germany.

Objective: For correct implant planning based on cone-beam computed tomography (CBCT), the bone contour must be accurately determined. Identification of the contour is difficult in bones with incomplete mineralization. In this clinical study, we investigated the intrapersonal and interpersonal reproducibilities of manual bone contour determination on CBCT images using a semi-automated computerized process.

Methods: The bone surface level in the area of the socket in 20 patients who had undergone tooth extraction from the upper jaw at 10 ± 1 weeks previously was determined on CBCT images. Two investigators with different levels of experience determined the bone structure initially (T) and repeated the procedure after 3 months (T). The bone structure marked on CBCT images was converted into a surface data set. The resulting data sets were superimposed on one another. In the analyses, the shortest distances between the datasets were identified and measured. The average deviations were statistically evaluated.

Results: The intrapersonal evaluation resulted in an average deviation of 0.18 mm across both investigators. The interpersonal analysis comparing the two investigators resulted in average deviations of 0.15 mm at T and 0.26 mm at T. Significant differences were not found.

Conclusions: The low intrapersonal deviation indicates that the procedure has satisfactory reproducibility. All deviations were within the range of the selected resolution of the CBCT device. Application of a semi-automated procedure to detect the bone border in areas with incomplete mineralization is a predictable process.

Trial Registration: The study was registered in the German Clinical Trials Register and the International Clinical Trials Registry Platform of the WHO: DRKS00004769, date of registration: 28 February 2013; and DRKS00005978, date of registration: 09 November 2015.
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http://dx.doi.org/10.1007/s11282-018-0340-1DOI Listing
May 2019

Alveolar ridge preservation with a collagen material: a randomized controlled trial.

J Periodontal Implant Sci 2018 Aug 31;48(4):236-250. Epub 2018 Aug 31.

Department of Prosthetic Dentistry, Center of Dentistry, Ulm University, Ulm, Germany.

Purpose: Resorption of the alveolar bone is an unavoidable consequence of tooth extraction when appropriate alveolar ridge preservation (ARP) measures are not taken. The objective of this trial was to test the hypothesis that dimensional changes in the alveolar bone after tooth extraction would be reduced by inserting an equine collagen membrane and a collagen cone to fill and seal the alveolus (as ARP), in comparison to extraction with untreated alveoli.

Methods: In this randomized clinical trial, 31 patients were directly treated with the collagen material after extraction of a tooth from the maxilla (the ARP group). Twenty-nine patients served as the control group. After extraction, no further treatment (i.e., no socket preservation measures) was performed in the control group. Changes in the alveolar process immediately after extraction and after an 8 (±1)-week healing period were evaluated 3-dimensionally. Blinded analyses were performed after superimposing the data from the digitalized impressions and surfaces generated by cone-beam computed tomography.

Results: Both the ARP and control groups showed a reduction of bone in the alveolar area after tooth extraction. However, significantly less bone resorption was detected in the clinically relevant buccal region in the ARP group. The median bone reduction was 1.18 mm in the ARP group and 5.06 mm in the control group (=0.03).

Conclusions: The proposed hypothesis that inserting a combination material comprising a collagen cone and membrane would lead to a difference in alveolar bone preservation can be accepted for the clinically relevant buccal distance. In this area, implantation of the collagen material led to significantly less alveolar bone resorption. German Clinical Trials Register at www.drks.de, DRKS00004769.
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http://dx.doi.org/10.5051/jpis.2018.48.4.236DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6125670PMC
August 2018

Dimensional Changes of the Soft Tissue after Alveolar Ridge Preservation with a Collagen Material. A Clinical Randomized Trial.

Open Dent J 2018 30;12:389-399. Epub 2018 May 30.

Department of Prosthetic Dentistry, Center of Dentistry, University of Ulm, Ulm, Germany.

Background: Reduction of the soft tissue is an unavoidable consequence of tooth extraction without appropriate measures of Alveolar Ridge Preservation (ARP).

Objectives: The objective of this study is the volumetric investigation of the dimensional change of the soft tissue post tooth extraction to compare an Alveolar Ridge Preservation (ARP) measure with the insertion of a combination material with a collagen cone to fill the alveolus, combined with a collagen membrane, with untreated extraction alveoli.

Methods: In the context of a randomized clinical trial, 31 patients were treated with the combination material directly post tooth extraction in the maxilla (ARP). In 29 further patients, the extraction alveoli were left without further measures (control group).The changes of the soft tissue contour were measured 6 (+/- 1) weeks post extraction. The measurements were performed by superimposing digital models. The groups were compared using the Wilcoxon rank-sum-test.

Results: The premolar subgroup revealed a significant difference of the soft tissue dimension post insertion of a collagen material into the alveolus in comparison to untreated alveoli. In these cases, the mean loss of soft tissue volume after use of the collagen material was significantly lower.

Conclusion: The proposed hypothesis that there is a difference of the soft tissue preservation between alveoli with and without the use of a collagen material can be accepted with restrictions to the premolar region. A statistically significant lower volume reduction of the soft tissue by implantation of the collagen material could be detected with premolars.
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http://dx.doi.org/10.2174/1874210601812010389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5997874PMC
May 2018

Digital implantological workflow for a CAD/CAM immediate long-term temporary restoration for the edentulous maxilla.

Int J Comput Dent 2018;21(2):133-146

The rehabilitation of the edentulous jaw using angulated implants and screw-retained retrievable fixed prosthetic dentures is a well-established treatment method. Possible advantages include the option to avoid bone augmentation, to provide an immediate long-term provisional restoration, and, where appropriate, to perform a minimally invasive procedure. A variety of prosthodontic solutions are available for the definitive restoration, not least allowing the patient's financial situation to be accommodated. Implementing this concept requires systematic planning and an exacting surgical procedure. It makes sense to rely on a computer-assisted process for this purpose as it standardizes the procedure and makes it reproducible, with all the benefits this entails. The present report highlights the consistent integration of virtual planning and computer-aided design/computer-aided manufacturing (CAD/CAM), from the surgical template to the immediate long-term provisional restoration. The relevant procedures are described in general terms and illustrated by a patient case.
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October 2018

Precision of sleeveless 3D drill guides for insertion of one-piece ceramic implants: a prospective clinical trial.

Int J Comput Dent 2018;21(2):97-105

Objective: The insertion of implants through template-guided surgery is an established method. At the present time, the static navigation is based on sleeves integrated into the guides, through which drill bits of the corresponding size are passed. The present clinical trial is designed to test a new sleeveless system to determine the precision of implant insertion for one-piece ceramic implants.

Materials And Methods: For 12 patients, implant bed preparation and the insertion of the implants were done using a sleeveless implant guide. Twenty implants were inserted in this way and checked for precision. The check was done using a noninvasive method, which permitted comparison of the planning data with the actually realized positions after superimposition.

Results: The mean deviations were 0.52 mm (95% CI: 0.37 to 0.67 mm) at the crestal position of the implant, and 0.82 mm (95% CI: 0.56 to 1.08 mm) at the apical tip of the implant. The height deviation was 0.35 mm (95% CI: 0.01 to 0.68 mm). The mean angular deviation was measured as 2.85 degrees (95% CI: 2.18 to 3.51 degrees).

Conclusion: The values showed good precision in all the parameters measured. The results were thus in a range equal to or better than the mean precision found in numerous clinical trials described in the literature. In particular, the method showed little deviation, as illustrated by the confidence interval (CI), but also by the clinically critical maximum deviations.
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October 2018

Accuracy of the match between cone beam computed tomography and model scan data in template-guided implant planning: A prospective controlled clinical study.

Clin Implant Dent Relat Res 2018 Aug 25;20(4):541-549. Epub 2018 Apr 25.

Department of Prosthetic Dentistry, Center of Dentistry, University of Ulm, Germany and Private practice, Hilzingen, Germany.

Background: Template-guided implant placement is a method for optimal implant positioning from a prosthetic and surgical viewpoint. The treatment planning is based on three-dimensional X-ray data and model scan data, as well as on prosthetic planning (set-up). These data are matched (superimposed) with the aid of an X-ray template or by manual matching without special referencing.

Purpose: The objective of this prospective controlled clinical study was to determine and compare the accuracy of the match with and without an additional X-ray template.

Materials And Methods: The DICOM data of the cone beam computed tomography (CBCT) were converted into surface data sets and then superimposed on model scan data using three different methods (manually, based on an X-ray template, or semi-automatically with computer assistance). The mean deviations between these results of these matching methods were investigated.

Results: The procedures achieved a matching accuracy of 0.2 mm on average. This corresponds to the resolution of the CBCT (0.2 voxels). Further studies are necessary to verify the procedure even for patients with few (0-4) residual teeth.

Conclusion: In the presence of a sufficient number of residual teeth, the manual matching of model scan data with CBCT data is sufficiently accurate for implant planning and template-guided implementation. The results of the present study suggest that X-ray templates can be dispensed with saving the patient a substantial amount of time and money.
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http://dx.doi.org/10.1111/cid.12614DOI Listing
August 2018

3D accuracy of implant positions in template-guided implant placement as a function of the remaining teeth and the surgical procedure: a retrospective study.

Clin Oral Investig 2018 Jul 22;22(6):2363-2372. Epub 2018 Jan 22.

Department of Prosthetic Dentistry, Center of Dentistry, University of Ulm, Ulm, Germany.

Objective: The aim of this study was to investigate differences between the virtually planned and clinically achieved implant positions in completely template-guided implantations as a function of the type of edentulous space, the residual natural dentition, and the surgical implementation.

Materials And Methods: Fifty-six patient cases with a total of 122 implants were evaluated retrospectively. The implantations were completely template-based. The data of the planned implant positions were overlaid with the actual clinical implant positions, followed by measurements of the 3D deviations in terms of coronal (x) and apical distance, height (x), and angulation (ang) and statistical analysis.

Results: The mean x was 1.2 mm (SD 0.7 mm); the mean x was 1.8 mm (SD 0.9 mm), the mean x was 0.8 mm (SD 0.7 mm); and the mean ang was 4.8° (SD 3.1). The type of edentulous space and the jaw (maxilla/mandible) had no significant effect on the results in terms of implant positions. The presence of an adjacent natural tooth at the time of implantation had a significant influence on x (p = 0.04) and ang (p = 0.05). No significant differences were found regarding the surgical approach for any of the parameters examined.

Conclusion: The results of our study are in the same range as those of other studies. Template-guided implantation offers a high degree of accuracy even in the presence of different configurations of the residual dentition or different surgical approaches. A clinical benefit is therefore present, especially from a prosthetic point of view.

Clinical Relevance: The clinically achievable accuracy can be described as sufficient for further prosthetic treatment, given the intrinsic and methodological tolerances, making prosthetic rehabilitation safe and predictable.
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http://dx.doi.org/10.1007/s00784-018-2339-8DOI Listing
July 2018

Retrospective study to determine the accuracy of template-guided implant placement using a novel nonradiologic evaluation method.

Oral Surg Oral Med Oral Pathol Oral Radiol 2016 Apr 4;121(4):e72-9. Epub 2016 Jan 4.

Clinic of Prosthetic Dentistry, Ulm University Hospital, Department of Dentistry, Ulm, Germany.

Objectives: With a novel, noninvasive method for determining three-dimensional accuracy, the realized implant position relative to the planned implant position was analyzed retrospectively. Additional postoperative cone beam computed tomography was thus dispensable.

Study Design: Twelve cases with distal extension situations (DESs) or single tooth gaps (STGs) were evaluated. The data sets of the planned implant position were superimposed on the actually achieved implant position, retrieved from digitizing the implant impression. The deviations were measured and statistically analyzed.

Results: The mean deviation was 5° in the DES group and 4° in the STG group for the implant axes, 1 mm (DES) and 0.9 mm (STG) at the implant neck, and 1.6 mm (DES) and 1.5 mm (STG) at the implant apex. The mean height discrepancy was 0.5 mm (DES) and 0.5 mm (STG). No significant differences (P > .05) were found between the DES and STG groups.

Conclusions: The innovative, noninvasive evaluation method is suitable and sufficiently accurate for the assessment of larger cohorts. The results of our study showed a sufficiently high degree of accuracy when using a virtual planning program for which no radiopaque template is needed when performing cone beam computed tomography.
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http://dx.doi.org/10.1016/j.oooo.2015.12.012DOI Listing
April 2016

Histological examination and clinical evaluation of the jawbone of an adult patient with cleidocranial dysplasia: a case report.

Int J Clin Exp Pathol 2015 1;8(7):8521-31. Epub 2015 Jul 1.

Department of Orthodontics, Oral Biology Laboratory, University of Bonn Germany.

Objectives: Cleidocranial dysplasia (CCD) is a rare congenital malformation syndrome, inherited autosomal-dominantly. During a course of treatment including surgical, implantological and restorative procedures, an opportunity arose to histologically examine biopsies of the maxilla and mandible of a CCD patient 47 years of age.

Case Report: The aim of this case report is to present the results of the histological evaluation of the alveolar bone and the surgical pretreatment for and placement of six implants each in the maxilla and the mandible. The implants were inserted in a minimally invasive procedure using 3D template guidance. Following uneventful healing of the implants, ceramically veneered bridges were cemented on individual titanium abutments. Since the patient had not received orthodontic treatment in childhood-which would have been the treatment modality of choice-this implantological and prosthodontic approach was necessary. Biopsies were taken from the maxilla and the mandible before placing the implants. Histological evaluation showed bone with strong, coarsely interconnecting trabeculae, especially in the maxilla. Both the bone and the gingiva otherwise exhibited a normal structure without pathological features or anomalies.

Conclusion: The clinical parameters and histological evaluation of this one clinical case suggest that the concepts familiar from general oral implantology in terms of surgical and prosthetic procedures can be adopted for older patients with CCD.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4555756PMC
June 2016
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