Aim: To review available evidence in scientific literature on oral implants of severely reduced length or diameter. Materials and methods: Electronic and hand searches up to May 2017 were performed in order to identify clinical investigations providing implant survival and/or marginal bone resorption data for extra-short implants < 7.0 mm in length and extra-narrow implants < 3.5 mm in diameter (excluding one-piece mini-implants). Results: A total of 2929 extra-short implants and 3048 extra-narrow diameter implants were investigated in 53 and 29 clinical studies, respectively. Shorter implants between 4.0 mm and 5.4 mm in length showed comparable results to implant lengths of 5.5 mm to 6.5 mm (95.1% vs. 96.4%, P = 0.121) and no difference regarding marginal bone resorption (0.7 mm vs 0.5 mm, P = 0.086). Implant lengths of 5.5 mm to 6.5 mm, however, performed significantly better in the mandible compared with the maxilla (P = 0.010). Smaller diameters between 3.0 mm and 3.25 mm yielded a significantly lower survival rate of 94.3% than wider implants of 3.3 mm to 3.4 mm diameter (97.7%, P < 0.001), while marginal bone resorption did not differ (0.4 mm vs 0.5 mm, P = 0.447). Conclusions: The results of the present literature review suggest that extra-short and extra-narrow-diameter implants show satisfactory survival rates of around 95% and little marginal bone resorption of around 0.5 mm after a mean follow-up of 3 years. However, implant lengths < 7 mm in the maxilla and < 5.5 mm in the mandible as well as diameters < 3.3 mm may increase early failure rates. Schlagwörter: decision making, dental implants, evidence-based dentistry, implant-supported dental prosthesis, patient preference

Purpose: To evaluate the use of chemically unchanged tooth material in lateral alveolar ridge augmentation or for the filling of jaw defects. Materials and Methods: A total of 20 patients underwent either lateral augmentation of the alveolar process (11 patients) or filling of jaw defects (6 patients) with autogenous unaltered tooth material in a longitudinal 2-year study. In three patients, the jaw defect was so marked that a bone block graft had to be used for augmentation in addition to particulate dental material. In four patients, an autogenous tooth block was exclusively used; in seven, crushed tooth material was exclusively used; and in the remaining six, dystopic teeth that had been extracted were removed, crushed, and reinserted into the defect in particulate form. Fully impacted teeth served as autogenous donor teeth. Results: After a healing time of 3 to 6 months, 28 implants could be placed (10 immediate implants, 18 delayed implants). At 6, 12, and 24 months postrestoration, peri-implant bone loss as assessed by x-ray was 0 mm, 0.4 mm, and 0.6 mm, respectively. Peri-implant probing depth was 1 mm after 1 year and 2 mm after 2 years. Bleeding on probing was not seen in any of the implants after 2 years. Conclusion: Autogenous tooth material appears to be suitable for the restoration of lateral and intraosseous defects of the alveolar ridge with both complete blocks and in particulate form. However, additional long-term studies with higher case numbers will be required for substantiating these results. Schlagwörter: alveolar ridge reconstruction, autogenous bone graft, autogenous tooth, bone substitutes, implants

Purpose: To compare long-term survival and marginal bone loss of immediate interantral implants in the nonaugmented maxilla subjected to immediate vs delayed loading. Materials and Methods: Graftless maxillary cross-arch rehabilitation was performed in a total of 362 patients in the years 2004 to 2013 (1,797 implants). Of the 240 patients with immediate implants replacing their failing maxillary dentition, 81% were subjected to immediate loading and 19% to delayed loading of their 4 to 6 interantral implants (980 and 235 implants, respectively). Kaplan-Meier survival estimates were computed and marginal bone loss was evaluated in a stratified random sample of 20 patients per group. Results: Thirty-one of 1,215 implants failed within the mean observation period of 3.9 years, and no difference in 8-year survival estimates could be seen between immediate (97.6% [95% CI: 96.7 to 98.6]) and delayed (96.6% [95% CI: 94.3 to 98.9]) loading protocols (P = .359). Mean marginal bone resorption following implant insertion did not differ significantly between the groups (1.5 ± 1.7 mm vs 0.7 ± 1.1 mm, P = .379); however, it was significantly associated with a reduced number of implants (P = .017) and patient history of periodontal disease (P < .001). Conclusion: Immediate loading of interantral implants yields satisfactory results in the transition of patients from a failing maxillary dentition to full-arch implant rehabilitation and thus may be favored over delayed loading concepts. Schlagwörter: complete denture, dental implants, edentulous arch, immediate dental implant loading, implantsupported dental prosthesis, maxilla

Purpose: To compare long-term survival and marginal bone loss of late interantral implants in the nonaugmented edentulous maxilla subjected to immediate vs delayed loading. Materials and Methods: One hundred twenty-two edentulous patients with implants in native, healed jawbone were subjected to either immediate loading (179 implants) or delayed loading (403 implants) of their four to six interantral implants (part I of 362 graftless maxillary cross-arch rehabilitations performed in the years 2004 to 2013). Kaplan-Meier survival estimates were computed, and marginal bone loss was evaluated in a stratified random sample of 20 patients per group. Results: Fifteen of 582 implants failed within the mean observation period of 4.7 years, and no difference in 8-year survival estimates could be seen between immediate (98.3% [95% CI: 96.4-100.0]) and delayed (96.7% [95% CI: 94.7-98.6]) loading protocols (P = .370). Mean marginal bone resorption following implant insertion did not differ significantly between the groups (1.1 ± 1.3 mm vs 1.4 ± 1.3 mm, P = .490). Conclusion: Immediate loading of interantral implants in the nonaugmented edentulous maxilla yields favorable results comparable to delayed loading and may be considered to shorten periods of removable provisional prostheses in maxillary edentulism. Schlagwörter: complete denture, dental implants, edentulous arch, immediate dental implant loading, implantsupported dental prosthesis, maxilla

Purpose: Failing residual dentition gives rise to patient concerns about the surgical and prosthodontic management of immediate implant rehabilitation. The purpose of this study was to assess subjective patient experiences of full-arch immediate implant loading. Materials and Methods: Patients made a transition from poor dentition in the maxilla (25 patients) or mandible (25 patients) to full-arch rehabilitation on the day of extraction using four interantral or interforaminal implants. Provisional restoration was performed, and postoperative pain, swelling, and patient-perceived impairment in the first week was recorded. Results: Absence of pain was reported by 40%, 52%, and 66% of patients, on the day of surgery, on the first day after surgery, and on the second day after surgery, respectively; pain levels decreased significantly (from 1.8 to 0.9, P < .001) and patient-reported swelling decreased from 1.5 to 1.3 (P = .058) on a 10-point scale. Postoperative impairment of everyday life and work (mean score = 1.1) was significantly less pronounced than impairment of food intake (mean score = 2.2; P = .004) or speech (mean score = 1.9; P = .002). Of these patients, 88% would again undergo the procedure without doubt. Conclusion: Although patient-perceived morbidity after immediate full-arch implant rehabilitation is low in general, minor masticatory and phonetic impairment should be taken into account. Schlagwörter: complications, dental implants, immediate dental implant loading, implant-supported dental prosthesis, patient satisfaction, quality of life

Prosthodontically driven biomechanical considerations are essential for longterm successful outcomes in dental implant therapy. Correct protocols seek to preclude potential consequences associated with functional and parafunctional occlusal overload such as screw loosening, component fracture, compromised marginal bone maintenance, and the integrity of the induced osseointegration response. Other concerns also need to be addressed, more especially when other implants are selected, for example: bridge insertion torque (BIT) in cases of immediate loading, cantilever length-anteroposterior spread ratio (CL-AP), overall crown-to-implant ratio (oCIR), total bone-to-implant surface area (tBICA), and the status of the opposing dentition. In spite of promising clinical results, evidencebased clinical protocols demand that such biomechanical limits still need to be determined.

Purpose: To evaluate patient satisfaction, oral health-related quality of life, and patients' preferences towards minimally invasive treatment options for graftless rehabilitation of complete edentulism by means of dental implants. Material and methods: A MEDLINE search of literature in the English language up to the year 2013 was performed to summarise current evidence from the patient's perspective. The final selection included 37 studies reporting on minimally invasive implant treatment of 648 edentulous maxillae and 791 edentulous mandibles in 1328 patients, via a total of 5766 implants. Results: Patient satisfaction averaged 91% with flapless implant placement (range: 77 to 100%), 89% with short implants, 87% with narrow-diameter implants (range: 80 to 93%), 90% with a reduced number of implants (range: 77 to 100%), 94% with tilted implant placement (range: 58 to 100%), and 83% with zygomatic fixtures (range: 50 to 97%). Indirect comparison yielded patient preference towards tilted implant placement compared to a reduced number of implants (P = 0.036), as well as to zygomatic implants (P = 0.001). Conclusions: While little evidence on patients' preferences towards minimally invasive treatment alternatives vs. bone augmentation surgery could be identified from within-study comparison, it may be concluded that patient satisfaction with graftless solutions for implant rehabilitation of completely edentulous jaws is generally high. Comparative effectiveness research is needed to substantiate their positive appeal to potential implant patients and possible reduction of the indication span for invasive bone graft surgery. Schlagwörter: dental implants, implant-supported dental prosthesis, quality of life, patient preference, patient satisfaction Conflict-of-interest notification: The authors declare that they have no conflict of interest.

Purpose: In this experimental study, dental implants placed after maxillary sinus grafting with either porous hydroxyapatite (HA) (Interpore 200) or autogenous bone were examined for their mechanical stress tolerance. Materials and Methods: A total of 54 titanium plasma flame-sprayed cylindric implants were placed in the lateral sinus wall bilaterally of 27 mountain sheep. The bony sinuses were opened through an extraoral approach. Eighteen sinuses were grafted with porous HA, and another 18 were grafted with cancellous bone from the iliac crest. Eighteen non-grafted sinuses were used as controls. In the same operation, 2 cylindric implants were placed in each of the sinuses. One implant of each sinus was tested for mechanical strength of the bone-implant interface at 12, 16, and 26 weeks using pullout force. Results: The mean pullout force was 259.3 N in the control group, 356.7 N in the autogenous bone group, and 376 N in the HA group. Pooled data for the grafted sites showed the pullout force to be significantly higher than in the empty control sites (P = .02). The pullout force increased significantly with ongoing healing time (P = .02), but there was considerable variation within the groups. While the force remained more or less constant throughout the follow-up time in the controls (248 N at week 12 to 276 N at week 26), it increased dramatically in the group augmented with autogenous bone (223.8 N at week 12 to 523.16 N at week 26). The pullout force was initially highest in the HA group (302.3 N at week 12) and increased to 423.5 N at 26 weeks, but it did not reach the levels recorded in the autografted group. Discussion and Conclusion: Mechanical tests of bone-toimplant contact in a sheep model showed that HA for 1-stage sinus floor elevation significantly increased the pullout force versus ungrafted sinuses, although it was less than that found with autogenous bone after 26 weeks.