Accuracy of Dental Implant Placement with Dynamic Navigation-Investigation of the Influence of Two Different Optical Reference Systems: A Randomized Clinical Trial.

This randomized prospective clinical study aims to analyze the differences between the computer-assisted planned implant position and the clinically realized implant position using dynamic navigation. In the randomized prospective clinical study, 30 patients were recruited, of whom 27 could receive an implant (BLT, Straumann Institut AG, Basel, Switzerland) using a dynamic computer-assisted approach. Patients with at least six teeth in their jaws to be implanted were included in the study. Digital planning was performed using cone beam tomography imaging, and the visualization of the actual situation was carried out using an intraoral scan. Two different workflows with differently prepared reference markers were performed with 15 patients per group. The actual clinically achieved implant position was recorded with scan bodies fixed to the implants and an intraoral scan. The deviations between the planned and realized implant positions were recorded using evaluation software. The clinical examinations revealed no significant differences between procedures A and B in the mesiodistal, buccolingual and apicocoronal directions. For the mean angular deviation, group B showed a significantly more accurate value of 2.7° (95% CI 1.6-3.9°) than group A, with a value of 6.3° (95% CI 4.0-8.7°). The mean 3D deviation at the implant shoulder was 2.35 mm for workflow A (95% CI 1.92-2.78 mm) and 1.62 mm for workflow B (95% CI 1.2-2.05 mm). Workflow B also showed significantly higher accuracy in this respect. Similar values were determined at the implant apex. The clinical examination shows that sufficiently accurate implant placement is possible with the dynamic navigation system used here. The use of different workflows sometimes resulted in significantly different accuracy results. The data of the present study are comparable with the published findings of other static and dynamic navigation procedures.

Digital Evaluation of Vertical Ridge Augmentation with the Modified Shell Technique Using a Xenogeneic Bone Lamina: A Case Series.

Vertical ridge augmentation is a demanding and technique-sensitive surgical procedure. In the present case series, cone beam CT (CBCT) scans from the clinical routine of patients treated using a novel approach for vertical bone augmentation were assessed. All patients showed a single-tooth class 5 defect and were treated using a modification of the original shell technique. Cortical bone plates were replaced with a lamina composed of a partially demineralized porcine xenograft. CBCT scans of six consecutive patients were treated with the lamina and particulate bone from the mandibular ramus prior to a single tooth implant in the anterior maxilla were included. Pre- and postsurgical CBCT data sets were superimposed and analyzed digitally using surface matching and Boolean subtraction. The volume of the grafted area was calculated with and without the xenograft. The vertical gain of the ridge height measured in this case series varied from 7 to 11.3 mm. The mean vertical gain was 8.97 mm. The mean volume including the xenograft was 382.59 mm3 (SD 73.39) and 250.84 mm3 (SD 53.67) without the lamina. The modified shell technique used in this case series for the vertical augmentation of single-tooth class 5 defects provided sufficient bone for single implant restorations.

Technical Complications of Removable Partial Dentures in the Moderately Reduced Dentition: A Systematic Review.

The aim of this study was to conduct a systematic literature review with a subsequent meta-analysis on the technical complications and failures of removable partial denture (RPD) therapy in the moderately reduced dentition. A systematic literature search of established medical databases, last updated 06/2022, was conducted. RCTs and prospective and retrospective studies were included that had information on technical complications and failures of RPDs, at least 15 participants, an observation period of at least two years and a drop-out rate of less than 25%. Publications were selected on the title, abstract and full-text level by at least three of the participating authors. The evidence of the included studies was classified using the GRADE system. The bias risk was determined using the RoB2 tool and the ROBINS-I tool. Of 19,592 initial hits, 43 publications were included. Predominantly, retention of the prosthesis, retention loss of anchor crowns (decementations), fractures/repairs of frameworks, denture teeth, veneering or acrylic bases, and a need for relining were reported depending on prosthesis type and observation time. Focusing on technical complications and failures, only very heterogeneous data were found and publications with the highest quality level according to GRADE were scarce. Whenever possible, data on technical complications and failures should be reported separately when referencing the tooth, the prosthesis and the patient for comparability. Prostheses with differing anchorage types should be analyzed in different groups, as the respective complications and failures differ. A precise description of the kinds of complications and failures, as well as of the resulting follow-up treatment measures, should be given.

Orthodontic pretreatment with aligners for optimizing the result prior to fixed restorations in the esthetic zone.

OBJECTIVE: To show the benefit of a minor orthodontic pretreatment prior to fixed restorations in the esthetic zone in challenging situations. OVERVIEW: Esthetic rehabilitations in complex situations need careful treatment planning and comprehensive interdisciplinary approach. Minor orthodontic pretreatments may transfer complex situations into straight forward situations. Typical indications are space opening in order to provide space for a restoration with anatomic proportion or corrections of the tooth axis. CONCLUSION: This article presents three clinical cases that show how decision making can be facilitated by a functional and esthetic wax-up/mock-up workflow and how orthodontic pretreatment can contribute to a more functional, less invasive, and more esthetic outcome of restorative treatments in the esthetic zone. CLINICAL SIGNIFICANCE: Some complex cases in restorative dentistry can be transformed to straight forward cases with the help of minor orthodontic tooth movements.

Influence of the macrodesign of an implant and the sleeve system on the accuracy of template-guided implant placement: A prospective clinical study.

STATEMENT OF PROBLEM: Three-dimensional (3D) implant planning facilitates determining the optimal position and number of implants, in terms of function and esthetics, by taking into account adjacent structures. Template-guided implant placement is an established procedure for implementing this planning, although the accuracy between the planned and the actual implant position is subject to many influences. The influences of the macrodesign of the implants and the sleeve materials used have rarely been investigated clinically. PURPOSE: The purpose of this prospective clinical study was to investigate the accuracy of template-guided implant placement according to the macrodesign of different implants and the design of the drill sleeve. MATERIAL AND METHODS: Implants were placed in 60 participants within 3 groups (n=20): tapered implant with a metal sleeve (T-MS), tapered implant with a polymeric sleeve (T-PS), and progressive tapered implant with a polymeric sleeve (XT-PS). After overlaying the 3D implant planning image with the postoperative intraoral scan, deviations were 2-dimensionally related to the implant shoulder (S) and the apex (A) in terms of height (2DHS/2DHA), mesiodistal (2DSmd/2DAmd) and buccolingual (2DSbo/2DAbo), as well as 3-dimensionally on the implant shoulder (3DS), on the apex (3DA), and on the axis deviation (Axis). The groups were compared by using the analysis of variance. The Tukey post hoc test was performed for normally distributed data to identify significant differences among groups (α=.05). RESULTS: The errors for 2DSmd and 2DSbo were 0.26 to 0.40 mm across all groups. The 3DS group varied between 0.67 and 0.87 mm. No significant differences were found in terms of the material of the sleeves or the macrodesign of the implants (P>.05). Significant differences were found for 2DHS (P=.029) and 2DHA (P=.016) between the groups with the different sleeves. Group T-PS showed the least height deviation. CONCLUSIONS: In terms of height deviation, significant differences were found among the groups, with deviations depending on the implant type and the sleeve type. Overall, the method showed a high level of accuracy, providing good predictability of the prosthetic rehabilitation.

Quantification of MRP8 in immunohistologic sections of peri-implant soft tissue: Development of a novel automated computer analysis method and of its validation procedure.

BACKGROUND: As manual cell counting lacks objectivity in the assessment of positive marker cells in immunohistologic sections, there has been a shift to automated computer analysis solutions. However, quantifying inflammation around dental implants is still often done by manual cell counting. METHOD: With mucosal sections stained against MRP8 harvested around dental implants, we developed an automated method (AM) to identify positive marker cells. In this proof-of-concept study, we developed a procedure for its validation on an exemplary data set. Therefore, the sections were also analyzed with the manual method (MM). Intrarater and interrater reliability as well as time analyses were conducted. RESULTS: The newly developed AM was based on a color deconvolution in the open-source software ImageJ2. We embedded the determination of the most appropriate filter setting into the systematic validation procedure, implementing the intraclass correlation (ICC) and the Bland-Altman bias (BA). The newly developed validation procedure carried out on the data set of this proof-of-concept study resulted in an excellent reliability of the AM (ICC = 0.97). Both the reliability and time analyses' results were in favor of the AM. CONCLUSION: Our newly developed AM showed advantages in terms of repeatability and objectivity combined with a shorter duration. The detailed descriptions of its application and its validation procedure offers the opportunity to apply it for further immunohistologic questions. The prerequisite for the replacement of the MM is that the validation, carried out on a sufficient number of samples, leads to satisfactory results.

Dental and Maxillofacial Cone Beam CT-High Number of Incidental Findings and Their Impact on Follow-Up and Therapy Management.

Cone beam computed tomography (CBCT) is increasingly used for dental and maxillofacial imaging. The occurrence of incidental findings has been reported, but clinical implications of these findings remain unclear. The study's aim was to identify the frequency and clinical impact of incidental findings in CBCT. A total of 374 consecutive CBCT examinations of a 3 year period were retrospectively evaluated for the presence, kind, and clinical relevance of incidental findings. In a subgroup of 54 patients, therapeutic consequences of CBCT incidental findings were queried from the referring physicians. A total of 974 incidental findings were detected, involving 78.6% of all CBCT, hence 2.6 incidental findings per CBCT. Of these, 38.6% were classified to require treatment, with an additional 25.2% requiring follow-up. Incidental findings included dental pathologies in 55.3%, pathologies of the paranasal sinuses and airways in 29.2%, osseous pathologies in 14.9% of all CBCT, and findings in the soft tissue or TMJ in few cases. Clinically relevant dental incidental findings were detected significantly more frequently in CBCT for implant planning compared to other indications (60.7% vs. 43.2%, p < 0.01), and in CBCT with an FOV ≥ 100 mm compared to an FOV < 100 mm (54.7% vs. 40.0%, p < 0.01). Similar results were obtained for paranasal incidental findings. In a subgroup analysis, 29 of 54 patients showed incidental findings which were previously unknown, and the findings changed therapeutical management in 19 patients (35%). The results of our study highlighted the importance of a meticulous analysis of the entire FOV of CBCT for incidental findings, which showed clinical relevance in more than one in three patients. Due to a high number of clinically relevant incidental findings especially in CBCT for implant planning, an FOV of 100 × 100 mm covering both the mandible and the maxilla was concluded to be recommendable for this indication.

Gingival Displacement in the Vertical and Horizontal Dimension under the Condition of Mild Gingivitis-A Randomized Clinical Study.

This randomized clinical study aimed at quantifying the gingival displacement performance in the vertical and horizontal directions of the 3M™ Astringent Retraction Paste (3M Oral Care, Seefeld, Germany) in comparison with the double-cord technique with aluminum chloride as an astringent. Afterward, any soft-tissue changes were assessed for 12 months. After inducing mild gingivitis, 18 probands received the intervention 'cord' and 22 probands received the intervention 'paste' at the palatal half of upper premolars prior to conventional impression making. The resulting plaster casts were digitized and analyzed for the vertical and horizontal gingival displacement, applying a newly developed computer-assisted methodology. The entire palatal half of the tooth was evaluated instead of only single sites. Under the condition of mild gingivitis, the gingival displacement performance was comparable for both techniques in the horizontal direction (width) and only somewhat better for the cord technique in the vertical direction (depth). The magnitude of displacement was in a similar range in both directions, with somewhat higher values in the vertical direction. The marginal gingiva height changes were of such low extent during the follow-up period of 12 months with only minimally higher values for the paste that they cannot be considered as clinically relevant recessions.

Er:YAG laser-induced damage to a dental composite in simulated clinical scenarios for inadvertent irradiation: an in vitro study.

Inadvertent Er:YAG laser irradiation occurs in dentistry and may harm restorative materials in teeth. The aim of this in vitro study was to quantify Er:YAG laser-induced damage to a nanohybrid composite in simulated clinical scenarios for inadvertent direct and indirect (reflection) laser irradiation. The simulation was performed by varying the output energy (OE;direct˃indirect) reaching the specimen and the operating distance (OD;direct˂indirect). Composite specimens were irradiated by an Er:YAG laser. The ablation threshold was determined and clinically relevant parameters were applied (n = 6 for each OE/OD combination) for direct (OE: 570 mJ/OD: 10 mm, OE: 190 mJ/OD: 10 mm) and indirect irradiation (OE: 466 mJ/OD: 15 mm, OE: 57 mJ/OD: 15 mm, OE: 155 mJ/OD: 15 mm, OE: 19 mJ/OD: 15 mm). The extent of damage in the form of craters was evaluated using a laser scanning microscope (LSM) and a conventional light microscope (LM). The ablation threshold was determined to be 2.6 J/cm2. The crater diameter showed the highest value (LM: 1075 ± 18 µm/LSM: 1082 ± 17 µm) for indirect irradiation (reflectant:dental mirror) (OE: 466 mJ/OD: 15 mm). The crater depth showed the highest and comparable value for direct (OE: 570 mJ/OD: 10 mm; LSM: 89 ± 2 µm) and indirect irradiation (OE: 466 mJ/OD: 15 mm; LSM: 90 ± 4 µm). For each OD, the crater diameter, depth, and volume increased with higher laser fluence. However, the OD-and thus the laser spot diameter-also had an enlarging effect. Thus, indirect irradiation (reflectant:dental mirror) with only 47% of the laser fluence of direct irradiation led to a larger diameter and a comparable depth. The three-dimensional extent of the crater was large enough to cause roughening, which may lead to plaque accumulation and encourage caries, gingivitis, and periodontitis under clinical conditions. Clinicians should be aware that reflected irradiation can still create such craters.

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

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.

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

(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.

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

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 (p-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.

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

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.

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

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.

5-year randomized multicenter clinical trial on single dental implants placed in the midline of the edentulous mandible.

OBJECTIVES: This multicenter randomized controlled clinical trial was conducted to investigate whether the loading protocol of single dental implants placed in the midline of edentulous mandibles will influence the implant survival or prosthetic maintenance. MATERIALS AND METHODS: In total, 158 patients were randomly assigned either to the immediate loading group (n = 81) or to the delayed loading group (n = 77). All implants were loaded with an overdenture retained by a ball attachment. RESULTS: After 5 years, 102 patients attended the follow-up investigation. Immediately loaded single implants in the midline of the edentulous mandible revealed a statistically significant lower survival rate than implants loaded conventionally over an observation period of 5 years. In the immediate loading group, 9 implants failed within the first three months of implant loading. No further implant loss was recorded for this group. Two implants failed in the delayed loading group, whereas one implant had to be removed during second-stage surgery and the second five years after implant loading. Non-inferiority of the survival rate of the midline implant of the immediate loading group, compared with the delayed loading group, could not be shown (p = .79, CI immediate loading: 74.9%; 100.0%, CI delayed loading: 73.0%; 100.0%). The observed difference in implant survival between the two treatment groups over time was statistically significant. CONCLUSIONS: The results of the present study indicate that immediate loading of a single mandibular implant in the edentulous mandible should be considered only in exceptional cases.

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

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.

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

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.

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

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.

Stabilizing mandibular complete dentures by a single midline implant-influence on quality of life: 2-year results from a randomized clinical trial comparing different loading protocols.

OBJECTIVES: The knowledge about the influence of dental treatment on health-related quality of life (HRQoL) is still limited. The aim of this multicenter randomized controlled clinical trial was to assess the effect of stabilizing an existing complete denture, by means of a single mandibular implant, on HRQoL. Furthermore, the impact of the loading protocol, i.e., immediate or delayed loading, in edentulous patients was evaluated. METHODS: One hundred fifty-eight participants aged 60-89 years were randomly assigned to study group A (immediate loading; n = 81) and to group B (delayed loading; n = 78). All participants received a single midline implant in the mandible. The implants were either immediately loaded (group A) or after a closed healing period of 3 months (group B) by connecting the existing mandibular complete dentures to ball attachments. HRQoL was assessed with the Short Form-36 questionnaire of health (SF-36) at baseline, 4 months, and 24 months after implant loading. RESULTS: Improvement of HRQoL by means of a single implant-retained mandibular overdenture could not be demonstrated after 4 and 24 months of implant loading. Furthermore, the application of two different loading protocols did not influence HRQoL ratings of study participants. CONCLUSION: The loading protocol is not a factor, influencing HRQoL in patients treated by a single midline implant in the edentulous mandible. CLINICAL RELEVANCE: A single midline implant in the edentulous mandible, stabilizing a mandibular complete denture, cannot be recommended for improving HRQoL.