Inter- and intraindividual variability in virtual single-tooth implant positioning.

OBJECTIVES: The purpose of this prospective study was to determine the inter- and intraindividual variability in virtual single-tooth implant positioning based on the level of expertise, specialty, total time spent, and the use of a prosthetic tooth setup. MATERIALS AND METHODS: Virtual implant planning was performed on matched pre- and post-extraction intraoral scans (IOS), and cone-beam computed tomography scans of 15 patients. Twelve individual examiners, involving six novices and experts from oral surgery and prosthodontics positioned the implants, first based on anatomical landmarks utilizing only the post-extraction, and second with the use of the pre-extraction IOS as a setup. The time for implant positioning was recorded. After 1 month, all virtual plannings were performed again. The individual implant positions were superimposed to obtain 3D deviations using a software algorithm. RESULTS: An interindividual variability with mean angular, crestal, and apical positional deviations of 3.8 ± 1.94°, 1.11 ± 0.55, and 1.54 ± 0.66 mm, respectively, was found. When assessing intraindividual variability, deviations of 3.28 ± 1.99°, 0.78 ± 0.46, and 1.12 ± 0.61 mm, respectively, were observed. Implants planned by experts exhibited statistically lower deviations compared to those planned by novices. Longer planning times resulted in lower deviations in the experts' group but not in the novices. Oral surgeons demonstrated lower crestal, but not angular and apical deviations than prosthodontists. The use of a setup only led to minor adjustments. CONCLUSIONS: Substantial inter- and intraindividual variability exists during implant positioning utilizing specialized software planning. The level of expertise and the time invested influenced the deviations of the implant position during the planning sequence.

[Comprehensive Digital Workflow and Computer-Assisted Implant Surgery in a Patient with Reduced Crest Width. Case Report of a Split-Mouth Approach]. / Patienten-zentrierte digitale Implantologie. Minimalinvasiv und regenerativ: Implantattherapie bei reduzierter Kieferkammbreite mit volldigitalem Workflow. Fallbericht einer Split-Mouth-Behandlung.

Modern treatment protocols in implant dentistry focus on lower morbidity and patient-centered outcomes, in addition to commonly applied treatment success criteria. Prosthetically-driven digital planning followed by static computer-assisted implant surgery (sCAIS) may minimize the need for bone augmentation by ideally utilizing the residual crest and thereby improve patient satisfaction. A healthy 37-year-old female suffered from agenesis of both second mandibular premolars and presented wide single-tooth gaps on both sides of the mandible with a moderate (left) and pronounced (right) horizontal bone deficiency. 3D implant planning allowed ideal implant positioning in the residual bone volume while respecting critical anatomical structures. This enabled a flapless sCAIS procedure without bone grafting in the left mandible. On the right side, the insufficient bone volume was augmented simultaneously to the sCAIS using GBR. The clinical and radiographic parameters showed a good oral health status in the 1-year postop examination. The final implant position presented a minimal angular and horizontal deviation from the initial planning. The patient was highly satisfied with the two applied methods but preferred the flapless procedure.

Digital workflow for implant-supported fixed complete dentures based on backwards planning in an edentulous patient.

AIM: This case report describes a digital workflow for prosthetically driven surgical planning, implant placement, and the fabrication of two screw-retained, complete-arch, implant-supported dentures in an edentulous patient. The purpose of this case report is to present and discuss the digital steps in the workflow, especially the scanning technique to obtain the centric relation, through a clinical case. The limitations of the workflow are also discussed. MATERIALS AND METHODS: Static computer-aided implant surgery (s-CAIS) was planned three-dimensionally, based on cone beam computed tomography, intraoral optical scanning, and digital bite registration. Using s-CAIS, four and six implants were placed in the edentulous mandible and maxilla, respectively. The final screw-retained complete-arch monolithic zirconia restorations were manufactured based on a digital workflow, using the pre-existing modified radiologic guide for the digital maxillomandibular record. CONCLUSIONS: The evolution of digital processing methods allows for design, processing, and fabrication of implant-supported fixed complete dentures using a surgical, prosthetic, and technical workflow based on 3D restorative backward planning. A digital prosthetic setup and CAD/CAM can be used for the fabrication of intraoral try-ins that serve as a model for the final monolithic zirconia superstructure.

A retrospective analysis of autotransplanted teeth including an evaluation of a novel surgical technique.

OBJECTIVES: To assess survival rates and frequency of complications for immature and mature autotransplanted teeth after at least 1 year in function. MATERIALS AND METHODS: All consecutive patients who had undergone tooth autotransplantation between 2000 and 2018 were invited to a clinical and radiographic follow-up examination. First, survival rates were calculated on the basis of a phone inquiry. A clinical follow-up examination allowed for the calculation of the success rate, i.e., absence of any potentially adverse clinical and radiographic findings of the autotransplanted teeth. Moreover, the effect of demographic, dental, and surgical variables on survival/success was analyzed statistically. RESULTS: Thirty-eight teeth in 35 patients were transplanted during the study period. Three teeth in 3 patients were excluded due to missing records. All other patients were successfully contacted and interviewed by phone. Out of these 35 transplants, 32 were still in function, and 3 had been extracted, yielding a 91.4% survival probability after a median follow-up of 3.4 years. Of the 32 teeth qualifying for the success analysis, 20 (62.5%) showed absence of potentially adverse findings, while 3 (9.4%) required root canal treatment (RCT). Out of the 9 mature, root-end resected transplants, 4 exhibited ongoing pulp canal obliteration, all with a single root canal. Postoperative and potentially adverse findings or failures were found more frequently in the group of mature transplants (55.6%) than immature transplants (30.4%) and for molars (72.7%) than premolars (17.6%) or canines (25%). None of the potential predictors had a statistically significant effect on survival or success. CONCLUSION: Autotransplanted teeth yielded a satisfying midterm survival rate regardless of their stage of development. An additional, extraoral root-end resection of mature transplants may lead to rates of revascularization and postoperative pulp canal obliteration higher than the data reported on unmodified mature transplants. CLINICAL RELEVANCE: Extraoral root-end resection of mature teeth shows promising outcomes for transplants especially with a single root canal and uncomplicated root morphology.

Mandibular implant-supported fixed complete dental prostheses on implants with ultrashort and standard length: A pilot treatment.

Edentulous patients may be restored with complete-arch implant-supported fixed complete dental prostheses (IFCDPs) on angled distal implants or on parallel implants distributed equally across the mandible to increase the area of support. A treatment is presented to introduce the clinical concept of providing edentulous patients with an implant-supported fixed complete dental prosthesison parallel tissue-level implants in the mandible with standard length implants interforaminally and ultrashort implants distally. A structured prosthetic approach was used for the tooth arrangement with a modified workflow as per the Biofunctional Prosthetic System adapted for static computer-aided implant surgery (s-CAIS) and computer-aided design and computer-aided manufacturing (CAD-CAM) of the screw-retained implant-supported fixed complete dental prosthesis. The concept offered advantages in challenging anatomic, surgical, and prosthetic conditions; providing distal nonangled abutments and implant platforms, which were straightforward to clean. If necessary, the prosthesis could have been easily converted into a removable overdenture using the existing digital prosthetic arrangement. Should implant removal be required, the extrashort implants can be removed with minimal surgical risk or morbidity.

Bioceramic root repair material (BCRRM) for root-end obturation in apical surgery. An analysis of 174 teeth after 1 year.

The objective of this paper was the analysis of the 1-year outcome of teeth treated with apical surgery and a recently introduced bioceramic root repair material (BCRRM) for root-end filling. Patients were consecutively enrolled from 2015 to 2017. Apical surgery included the modern technique, i.e. the use of a surgical microscope, ultrasonic preparation of a root-end cavity, and retrofilling with BCRRM. The cohort comprised 150 patients with 174 treated teeth. Patients were recalled one year after surgery for a clinical and radiographic re-examination. Three experienced observers evaluated the periapical radiographs with regard to periapical healing utilizing the healing criteria established by Rud et al. (1972) and Molven et al. (1987). Based on the clinical findings and the radiographic assessment, healing was judged as successful, uncertain, or failed. Study parameters included gender, age, type of treated tooth, and type of BCRRM (regular vs. fast set putty). At the 1-year follow-up, 170 teeth could be reexamined (drop-out rate 2.3%). Healing outcome was categorized as successful in 94.1%, uncertain in 4.1%, and failed in 1.8%. No significant differences were observed when comparing the success rates among the different subcategories of study parameters. The lowest success rate was noted in mandibular premolars (86.7%) but without reaching statistical significance. In conclusion, BCRRM appears to be a biocompatible root-end filling material showing excellent 1-year results. The success rate was similar to recently reported success rates for BCRRM in apical surgery.

Crestal bone response to loaded zirconia and titanium implants: a radiographic and histometric analysis in canines.

OBJECTIVES: To evaluate the crestal bone response to a two-piece zirconia implant compared with a control titanium implant using periapical radiographs (PAs) and histometry. MATERIALS AND METHODS: Thirty zirconia and 30 titanium implants were placed in healed posterior mandibles of five canines. Full-ceramic single-tooth restorations were cemented after 6 weeks of healing. Three observers measured the distance between the implant shoulder and the crestal bone (DIB) at placement, loading, and harvesting after 4 or 16 weeks in function. The influence of implant material and loading time on DIB as well as the inter-observer agreement were analyzed. Additionally, histometric distance between implant shoulder and most coronal bone-to-implant contact (IS-cBIC) was compared with DIB. RESULTS: Mean DIB values increased between 4 and 16 weeks of loading for both zirconia (from 1.66 to 2.25 mm; P < 0.0001) and titanium (from 1.81 to 1.95 mm; P = 0.06). Zirconia yielded mean IS-cBIC values of 2.18 mm and 2.48 mm (P < 0.001) and titanium 2.23 mm and 2.34 mm (P = 0.27) after 4 and 16 weeks, respectively. The raters reached an excellent intraclass correlation coefficient. PAs underestimated the bone loss on average by 0.39 mm. CONCLUSIONS: Zirconia implants showed a greater increase of DIB during early healing and function than titanium. CLINICAL RELEVANCE: Crestal peri-implant tissue dimensions may show more pronounced changes around two-piece zirconia implants during early healing. PAs may underestimate peri-implant bone loss.

Unique air inclusions within the nasopalatine duct indicating its presence radiographically: a case presentation.

The anterior maxilla is characterized by the nasopalatine canal that originates bilaterally from the anterior nasal floor, subsequently fuses, and terminates at the incisive foramen in the anterior palate. Embryologically, this structure forms within the primary palate, and contains the neurovascular bundle, but also continuous epithelialized bands. The latter, termed nasopalatine ducts, usually degenerate and/or obliterate before birth. However, in some individuals, the ducts may remain partially or completely patent. The present case report describes for the first time in the literature a rare finding of air inclusions within the anatomical area of the nasopalatine canal indicating the presence of a nasopalatine duct as visualized with cone beam computed tomography. The patient was asymptomatic and the radiographic findings were seen incidentally. An endoscopic inspection of the anterior nasal cavities confirmed the presence of the nasal openings of the partially patent nasopalatine ducts.

Sinus floor elevation or referral for further diagnosis and therapy: A comparison of maxillary sinus assessment by ENT specialists and dentists using cone beam computed tomography.

OBJECTIVES: To compare ear, nose, and throat (ENT) specialists and dentists assessing health or pathology of maxillary sinuses using cone beam computed tomography (CBCT). MATERIAL AND METHODS: Two ENT specialists and two oral surgeons assessed 100 CBCT datasets of healthy patients referred for dental implant placement in the posterior maxilla and decided on the possibility of sinus floor elevation or the necessity for further diagnostic examinations based solely on radiographic findings. Inter-rater agreements within the same specialty were calculated with Cohen's kappa and overall agreements with Fleiss kappa, and factors influencing the decisions taken were evaluated using regression analyses. RESULTS: The correlation between all four raters was generally fair to moderate. The intra-specialty comparison showed a lower correlation between dentists than between ENT specialists. Absence of membrane thickening and total or subtotal sinus opacification showed the highest predictive value for a consensus in favor of sinus floor elevation and ENT referral, respectively. Flat membrane thickening with an irregular surface morphology was associated with disagreement between the examiners. Dome-shaped membrane thickenings were often considered as to be referred by dentists but not by ENTs. CONCLUSION: The assessment of maxillary sinuses using CBCT imaging exhibited unsatisfactory agreement between ENT specialists and oral surgeons. Referral guidelines based on accidental CBCT findings that aim to diagnose relevant sinus pathologies early and avoid unnecessary diagnostics and/or therapies are needed, and an initial proposal for such recommendations is provided. Further research on correct interpretation of sinus findings and a validation of the present recommendations are required.

Radiographic Assessment of Bone Healing Using Cone-beam Computed Tomographic Scans 1 and 5 Years after Apical Surgery.

INTRODUCTION: The objective of this long-term study was to evaluate radiographic healing in cone-beam computed tomographic (CBCT) scans taken 1 and 5 years after apical surgery. METHODS: In the context of a prospective clinical study, postsurgical CBCT scans were taken 1 and 5 years after apical surgery. Three calibrated observers independently assessed buccolingual CBCT images oriented along the longitudinal axis of the treated roots. Radiographic periapical healing was categorized as "fully, partially, or not healed" for each of the following study parameters: the resection plane, the cortical plate, the apical area, and the overall bone healing. The analysis included the interobserver agreement (Fleiss kappa values), the comparison of 5- and 1-year ratings, and the changes of healing categories from 1-5 years (McNemar-Bowker tests). Data were analyzed statistically for the detection of significant differences. RESULTS: CBCT images of 41 teeth (in 41 patients) with 47 treated roots were evaluated. At 5 years, all studied parameters had higher rates of fully healed cases compared with the rate at 1 year. The resection plane and apical area parameters each were judged in 72.3% as fully healed at 5 years, whereas the cortical plate and overall bone healing parameters showed clearly lower fully healed rates (42.6% and 38.3%, respectively). Fully healed cases at 1 year remained so at 5 years in 87.5%-100% depending on the study parameter. CONCLUSIONS: This 5-year CBCT follow-up study of apical surgery showed a marked improvement of radiographic healing from 1-5 years but to a varying degree regarding the different study parameters. Although new hard tissue formation at the resection plane and within the former apical defect was advanced in most cases at 5 years, the reestablishment of the cortical bone plate clearly lagged behind.

Influence of surgical guide support and implant site location on accuracy of static Computer-Assisted Implant Surgery.

OBJECTIVE: To investigate the effect of surgical guide support and implant site location on the accuracy of static Computer-Assisted Implant Surgery (sCAIS) in partially edentulous patients. MATERIALS AND METHODS: 375 replica implants were inserted in 85 study models. Surgical implant placement was done using static 3D printed surgical guides, which were designed to be supported either by all the teeth present in the model (full arch), or by 4-teeth), 3-teeth or 2-teeth. Each study model included three single-tooth gap (STG) situations; one extraction socket site and two implants placed in a distal extension situation. Preplanned and postoperative implant positions were compared using the treatment-evaluation tool in digital software. 3-dimensional and angular deviations were measured. Statistical analysis was done using ANOVA, and pairwise t tests and Bonferroni-Holm's adjustment were applied as a post hoc test. RESULTS: Accuracy of surgical guides used in sCAIS was significantly affected by the number and type of teeth used for its support. Guides supported by 4 teeth were not significantly different from accuracy of full-arch-supported guides (p > .05). Guide support by posterior teeth was associated with an increased level of accuracy, when compared to anterior teeth guide support. Implants placed in extraction sockets were associated with significantly higher 3D and angular deviation values (p < .05), and surgical guides with a distal extension situation resulted in significantly higher deviation values (p < .05). CONCLUSION: The number and location of teeth supporting the surgical guide can significantly influence the accuracy of sCAIS, with 4 teeth providing equal accuracy to full-arch guides in (STG) situations.

A 10-year Follow-up Study of 119 Teeth Treated with Apical Surgery and Root-end Filling with Mineral Trioxide Aggregate.

INTRODUCTION: The objective of this clinical study was to assess the long-term outcome (clinical signs/symptoms and radiographic healing) of teeth treated with apical surgery and mineral trioxide aggregate (MTA) for root-end filling. METHODS: One hundred ninety-five patients were recalled 1, 5, and 10 years after apical surgery for clinical and radiographic examinations. Three calibrated observers evaluated the periapical radiographs independently. The evolution of the cases over time was analyzed. Healing classification of teeth was divided into "healed" versus "not healed" teeth using well-established clinical and radiographic healing criteria. The potential influence of sex, age, type of treated tooth, type of MTA, and first-time versus repeat surgery on healing outcome was statistically analyzed. RESULTS: The inception cohort included 195 teeth. The dropout rate after 10 years amounted to 39% (n = 76). Of the 119 teeth available for the 10-year analysis, 97 teeth were classified as healed (81.5%). No significant differences were found with regard to the rate of healed cases for the subcategories of the parameters of age, sex, type of MTA, and first-time or repeat surgery. Concerning the type of treated tooth, the rate of healed maxillary molars (95.2%) differed significantly (P = .035) from the rate of healed maxillary premolars (66.7%). The predictive value of the cases classified as healed at 1 year and remaining so over the 10-year observation period was 86.8%. CONCLUSIONS: This 10-year follow-up study of teeth treated with apical surgery and MTA as root-end filling material showed an acceptable rate of healed cases. Many of the lost teeth had been extracted because of longitudinal root fractures during the observation period.

The influence of guided sleeve height, drilling distance, and drilling key length on the accuracy of static Computer-Assisted Implant Surgery.

OBJECTIVE: The aim of this study was to evaluate the effect of guided sleeve height, drilling distance, and guided key height on accuracy of static Computer-Assisted Implant Surgery (sCAIS). MATERIALS AND METHODS: Pre and post-operative positions of implants placed in duplicate dental models were compared and recorded after placement of implants according to a standardized treatment planning and execution sCAIS protocol. Guided sleeve heights: 2 mm, 4 mm, 6 mm and guided key heights: 1 mm and 3 mm were equally randomized in six test groups with varying implant lengths (10-16 mm) and surgical drilling protocols. The mean crestal and apical three-dimensional (3D) deviation, as well as the angular deviation were calculated for each group. Data was analyzed using multivariate analysis anova. P values less than .05 were considered statistically significant. All P values of post-hoc tests were corrected for multiple testing using Bonferroni-Holm's adjustment method. RESULTS: 3D implant positioning accuracy was not significantly affected by the difference in sleeve height alone or by the implant length alone (P > .05). However, 3D and angular deviation values became significantly higher as the total drilling distance below the guided sleeve increased and significantly became lower as the guided key height above the sleeve increased. 18 mm drilling distance resulted in a significantly higher deviation, when compared to 14 mm or 16 mm drilling distances, irrespective of sleeve height or implant length (P < .01). 3 mm key height resulted in significantly less 3D deviation than 1 mm key height (P < .01). CONCLUSION: Decreasing the drilling distance below the guided sleeve, by using shorter sleeve heights or shorter implants can significantly increase the accuracy of sCAIS.

Bone response to functionally loaded, two-piece zirconia implants: A preclinical histometric study.

OBJECTIVE: To evaluate the bone response to a two-piece zirconia implant in comparison with a control titanium implant in the canine mandible 4 and 16 weeks after restoration. MATERIAL AND METHODS: Zirconia and titanium implants were alternately placed bilaterally in healed mandibular molar and premolar sites of five canines. Full-ceramic single-tooth restorations were cemented after 6 weeks of transmucosal healing, allowing for full functional loading of the implants. Histologic and histometric analyses were performed on orofacial and mesiodistal undecalcified sections of the specimens obtained upon sacrifice after 4 and 16 weeks of functional loading. Bone-to-implant contact (BIC), multinucleated giant cells-to-implant contact (MIC), crestal bone level, and peri-implant bone density were histometrically assessed. RESULTS: All 60 implants and 60 restorations were still in function after 4 and 16 weeks of loading in both test and control groups. No implant loss, no implant or abutment fracture, and no chipping of the restorations could be detected. Histometric analysis showed no statistically significant differences between zirconia and titanium implants in BIC, crestal bone level, and peri-implant bone density at both time points. Between 4 and 16 weeks, the crestal bone level around zirconia implants showed a small but statistically significant increase in its distance from the implant shoulder. MIC was very low on both implant types and both time points and decreased statistically significantly overtime. CONCLUSION: The present two-piece zirconia implant showed a similar bone integration compared to the titanium implant with similar surface morphology after 4 and 16 weeks of loading.

The influence of collagen membrane and autogenous bone chips on bone augmentation in the anterior maxilla: a preclinical study.

OBJECTIVES: To evaluate the effect of a resorbable collagen membrane and autogenous bone chips combined with deproteinized bovine bone mineral (DBBM) on the healing of buccal dehiscence-type defects. MATERIAL AND METHODS: The second incisors and the first premolars were extracted in the maxilla of eight mongrels. Reduced diameter, bone-level implants were placed 5 weeks later. Standardized buccal dehiscence-type defects were created and grafted at implant surgery. According to an allocation algorithm, the graft composition of each of the four maxillary sites was DBBM + membrane (group D + M), autogenous bone chips + DBBM + membrane (group A + D + M), DBBM alone (group D) or autogenous bone chips + DBBM (group A + D). Four animals were sacrificed after 3 weeks of healing and four animals after 12 weeks. Histological and histomorphometric analyses were performed on oro-facial sections. RESULTS: The pattern of bone formation and resorption within the grafted area showed high variability among the same group and healing time. The histomorphometric analysis of the 3-week specimens showed a positive effect of autogenous bone chips on both implant osseointegration and bone formation into the grafted region (P < 0.05). The presence of the collagen membrane correlated with greater bone formation around the DBBM particles and greater bone formation in the grafted region after 12 weeks of healing (P < 0.05). The oro-facial width of the augmented region at the level of the implant shoulder was significantly reduced in cases where damage of the protection splints occurred in the first week of healing (P < 0.05). CONCLUSIONS: The addition of autogenous bone chips and the presence of the collagen membrane increased bone formation around DBBM particles. Wound protection from mechanical noxa during early healing may be critical for bone formation within the grafted area.

Evaluation of New Cone-beam Computed Tomographic Criteria for Radiographic Healing Evaluation after Apical Surgery: Assessment of Repeatability and Reproducibility.

INTRODUCTION: Conventional 2-dimensional radiography uses defined criteria for outcome assessment of apical surgery. However, these radiographic healing criteria are not applicable for 3-dimensional radiography. The present study evaluated the repeatability and reproducibility of new cone-beam computed tomographic (CBCT)-based healing criteria for the judgment of periapical healing 1 year after apical surgery. METHODS: CBCT scans taken 1 year after apical surgery (61 roots of 54 teeth in 54 patients, mean age = 54.4 years) were evaluated by 3 blinded and calibrated observers using 4 different indices. Reformatted buccolingual CBCT sections through the longitudinal axis of the treated roots were analyzed. Radiographic healing was assessed at the resection plane (R index), within the apical area (A index), of the cortical plate (C index), and regarding a combined apical-cortical area (B index). All readings were performed twice to calculate the intraobserver agreement (repeatability). Second-time readings were used for analyzing the interobserver agreement (reproducibility). Various statistical tests (Cohen, kappa, Fisher, and Spearman) were performed to measure the intra- and interobserver concurrence, the variability of score ratios, and the correlation of indices. RESULTS: For all indices, the rates of identical first- and second-time scores were always higher than 80% (intraobserver Cohen κ values ranging from 0.793 to 0.963). The B index (94.0%) showed the highest intraobserver agreement. Regarding interobserver agreement, the highest rate was found for the B index (72.1%). The Fleiss' κ values for R and B indices exhibited substantial agreement (0.626 and 0.717, respectively), whereas the values for A and C indices showed moderate agreement (0.561 and 0.573, respectively). The Spearman correlation coefficients for R, A, C, and B indices all exhibited a moderate to very strong correlation with the highest correlation found between C and B indices (rs = 0.8069). CONCLUSIONS: All indices showed an excellent intraobserver agreement (repeatability). With regard to interobserver agreement (reproducibility), the B index (healing of apical and cortical defects combined) and the R index (healing on the resection plane) showed substantial congruence and thus are to be recommended in future studies when using buccolingual CBCT sections for radiographic outcome assessment of apical surgery.

The resection angle in apical surgery: a CBCT assessment.

OBJECTIVES: The primary objective of the present radiographic study was to analyse the resection angle in apical surgery and its correlation with treatment outcome, type of treated tooth, surgical depth and level of root-end filling. MATERIALS AND METHODS: In the context of a prospective clinical study, cone beam computed tomography (CBCT) scans were taken before and 1 year after apical surgery to measure the angle of the resection plane relative to the longitudinal axis of the root. Further, the surgical depth (distance from the buccal cortex to the most lingual/palatal point of the resection plane) as well as the level of the root-end filling relative to the most coronal point of the cut root face was determined. Treated teeth were categorized into four groups (maxillary and mandibular anterior and posterior teeth). The final material comprised 62 treated roots in 55 teeth. RESULTS: The mean calculated resection angle of all roots was 17.7° ± 11.4° (range -9.6° to 43.4°). Anterior maxillary roots presented the highest mean angle (25.8° ± 10.3°) that was significantly different from the mean angle in posterior maxillary roots (10.7° ± 9.4°; p < 0.001) and from the mean angle in posterior mandibular roots (15.1 ± 9.8°; p < 0.05). In roots with a shallow resection angle (≤20°), the rate of healed cases was higher than in roots with an acute resection angle (>20°), however without reaching statistical significance (p = 0.0905). Angles did not correlate either with the surgical depth or with the retrofilling length. CONCLUSIONS: Statistically significant differences were observed comparing resection angles of different tooth groups. However, the angle had no significant effect on treatment outcome. CLINICAL RELEVANCE: Contrary to common belief, the resection angle in maxillary anterior teeth was greater than in the other teeth. The surgeon is advised to pay attention to the resection angle when bevelling maxillary anterior teeth in apical surgery.

Indications and Frequency for the Use of Cone Beam Computed Tomography for Implant Treatment Planning in a Specialty Clinic.

PURPOSE: To analyze the indications and frequency for three-dimensional (3D) imaging for implant treatment planning in a pool of patients referred to a specialty clinic over a 3-year period. MATERIALS AND METHODS: All patients who received dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology at the University of Bern were included in the study. The influence of age, gender, and time of treatment (2008 to 2010) on the frequency of use of two-dimensional (2D) radiographic imaging modalities alone or in combination with 3D cone beam computed tomography (CBCT) scans was analyzed. Furthermore, the influence of the indication, location, and need for bone augmentation on the frequency of use of 2D imaging modalities alone or in combination with CBCT was evaluated. RESULTS: In all, 1,568 patients (792 women and 776 men) received 2,279 implants. Overall, 633 patients (40.4%) were analyzed with 2D imaging procedures alone. CBCT was performed in 935 patients (59.6%). There was a statistically significant increase in CBCT between 2008 and 2010. Patients older than 55 years received a CBCT scan in addition to 2D radiographic imaging statistically significantly more often. Additional 3D imaging was most frequently performed in the posterior maxilla, whereas 2D radiographs alone exhibited the highest frequency in the anterior mandible. The combination of 2D with CBCT was used predominantly for implant placement with simultaneous or staged guided bone regeneration or sinus elevation. CONCLUSION: Based on these findings from a specialty clinic, the use of additional CBCT imaging for implant treatment planning is influenced by the indication, location, local anatomy (including the need for bone augmentation), and the age of the patient.

Implant therapy in a surgical specialty clinic: an analysis of patients, indications, surgical procedures, risk factors, and early failures.

PURPOSE: The aim of this study was to analyze the patient pool referred to a specialty clinic for implant surgery over a 3-year period. MATERIALS AND METHODS: All patients receiving dental implants between 2008 and 2010 at the Department of Oral Surgery and Stomatology were included in the study. As primary outcome parameters, the patients were analyzed according to the following criteria: age, sex, systemic diseases, and indication for therapy. For the inserted implants, the type of surgical procedure, the types of implants placed, postsurgical complications, and early failures were recorded. A logistic regression analysis was performed to identify possible local and systemic risk factors for complications. As a secondary outcome, data regarding demographics and surgical procedures were compared with the findings of a historic study group (2002 to 2004). RESULTS: A total of 1,568 patients (792 women and 776 men; mean age, 52.6 years) received 2,279 implants. The most frequent indication was a single-tooth gap (52.8%). Augmentative procedures were performed in 60% of the cases. Tissue-level implants (72.1%) were more frequently used than bone-level implants (27.9%). Regarding dimensions of the implants, a diameter of 4.1 mm (59.7%) and a length of 10 mm (55.0%) were most often utilized. An early failure rate of 0.6% was recorded (13 implants). Patients were older and received more implants in the maxilla, and the complexity of surgical interventions had increased when compared to the patient pool of 2002 to 2004. CONCLUSION: Implant therapy performed in a surgical specialty clinic utilizing strict patient selection and evidence-based surgical protocols showed a very low early failure rate of 0.6%.

Influence of particle size of deproteinized bovine bone mineral on new bone formation and implant stability after simultaneous sinus floor elevation: a histomorphometric study in minipigs.

BACKGROUND: Deproteinized bovine bone mineral (DBBM) is one of the best-documented bone substitute materials for sinus floor elevation (SFE). PURPOSE: DBBM is available in two particle sizes. Large particles are believed to facilitate improved neoangiogenesis compared with small ones. However, their impact on the rate of new bone formation, osteoconduction, and DBBM degradation has never been reported. In addition, the implant stability quotient (ISQ) has never been correlated to bone-to-implant contact (BIC) after SFE with simultaneous implant placement. MATERIALS AND METHODS: Bilateral SFE with simultaneous implant placement was performed in 10 Göttingen minipigs. The two sides were randomized to receive large or small particle size DBBM. Two groups of 5 minipigs healed for 6 and 12 weeks, respectively. ISQ was recorded immediately after implant placement and at sacrifice. Qualitative histological differences were described and bone formation, DBBM degradation, BIC and bone-to-DBBM contact (osteoconduction) were quantified histomorphometrically. RESULTS: DBBM particle size had no qualitative or quantitative impact on the amount of newly formed bone, DBBM degradation, or BIC for either of the healing periods (p > 0.05). Small-size DBBM showed higher osteoconduction after 6 weeks than large-size DBBM (p < 0.001). After 12 weeks this difference was compensated. There was no significant correlation between BIC and ISQ. CONCLUSION: Small and large particle sizes were equally predictable when DBBM was used for SFE with simultaneous implant placement.