The Curved Presplitting Technique in a Totally Edentulous Atrophic Mandible: A Surgical Case Report.

The management of horizontally fully edentulous atrophic ridges is a common problem in dental implantology. This case report describes an alternative modified two-stage presplitting technique. The patient was referred for an implant-supported rehabilitation of their edentulous mandible. CBCT scans showed a mean available bone width of about 3 mm. At the first stage, four linear corticotomies were performed using a piezoelectric surgical device. At the second surgical stage 4 weeks later, bone expansion was performed, and four implants were placed in the interforaminal area. The healing process was uneventful. No fractures of the buccal wall and no neurologic lesions were observed. Postoperative CBCT scans showed a mean bone width gain of about 3.7 mm. Implants were uncovered 6 months after the second surgery, and 1 month later, a fixed provisional screw-retained prosthesis was delivered. This approach could be used as a reconstructive technique that avoids using grafts and reduces treatment times, possible complications, postsurgical morbidity, and costs by exploiting the patient's native bone as much as possible. Considering the limitations of a case report, randomized controlled clinical trials are needed to confirm the results and validate this technique.

Extra-short (4-mm) implants placed after regenerative failures in the posterior atrophic mandible: A retrospective study.

PURPOSE: To explore whether extra-short (4-mm) implants could be used to rehabilitate sites where regenerative procedures had failed in order to avoid additional bone grafting. MATERIALS AND METHODS: A retrospective study was conducted among patients who had received extra-short implants after failed regenerative procedures in the posterior atrophic mandible. The research outcomes were complications, implant failure and peri-implant marginal bone loss. RESULTS: The study population was composed of 35 patients with 103 extra-short implants placed after the failure of different reconstructive approaches. The mean follow-up duration was 41.3 ± 21.4 months post-loading. Two implants failed, leading to a failure rate of 1.94% (95% confidence interval 0.24%-6.84%) and an implant survival rate of 98.06%. The mean amount of marginal bone loss at 5 years post-loading was 0.32 ± 0.32 mm. It was significantly lower in extra-short implants placed in regenerative sites that had previously received a loaded long implant (P = 0.004). Failure of guided bone regeneration before placement of short implants tended to lead to the highest annual rate of marginal bone loss (P = 0.089). The overall rate of biological and prosthetic complications was 6.79% (95% confidence interval 1.94%-11.70%) and 3.88% (95% confidence interval 1.07%-9.65%), respectively. The success rate was 86.4% (95% confidence interval 65.10%-97.10%) after 5 years of loading. CONCLUSIONS: Within the limitations of this study, extra-short implants seem to be a good clinical option to manage reconstructive surgical failures, reducing surgical invasiveness and rehabilitation time.

Osteoblasts and Fibroblasts Interaction with a Porcine Acellular Dermal Matrix Membrane.

The use of collagen membranes has remained the gold standard in GTR/GBR. In this study, the features and the biological activities of an acellular porcine dermis collagen matrix membrane applicable during dental surgery were investigated, and also by applying hydration with NaCl. Thus, two tested membranes were distinguished, the H-Membrane and Membrane, compared to the control cell culture plastic. The characterization was performed by SEM and histological analyses. In contrast, the biocompatibility was investigated on HGF and HOB cells at 3, 7, and 14 days by MTT for proliferation study; by SEM and histology for cell interaction study; and by RT-PCR for function-related genes study. In HOBs seeded on membranes, mineralization functions by ALP assay and Alizarin Red staining were also investigated. Results indicated that the tested membranes, especially when hydrated, can promote the proliferation and attachment of cells at each time. Furthermore, membranes significantly increased ALP and mineralization activities in HOBs as well as the osteoblastic-related genes ALP and OCN. Similarly, membranes significantly increased ECM-related and MMP8 gene expression in HGFs. In conclusion, the tested acellular porcine dermis collagen matrix membrane, mainly when it is hydrated, behaved as a suitable microenvironment for oral cells.

An Ancient Science to Improve Today's Clinical Practice: Oral Surgery Meets Human Anatomy.

Human body dissection was a ubiquitous practice in the past, to better understand anatomy and to develop medicine. Today, its role could still be important to answer everyday clinical queries and help surgeons. The example of the possible lack of anesthesia during symphysis surgeries can emphasize the usefulness of dissection. The mandibular symphysis usually receives innervation from inferior alveolar nerve terminations, but, in some rare cases, a particular anastomosis involves the lingual nerve and the nerve to the mylohyoid. The anatomical knowledge resulting from body dissections could help oral surgeons to understand the reason why the patient could feel pain during the surgery, and ensure performance of the right lingual nerve block to obtain complete anesthesia. This clinical situation shows the educational role of an ancient, yet still valid, practice, human dissection, and the importance of anatomical studies to improve surgical skills, to provide better treatment for the patient.

Dynamic Navigated "Sandwich" Technique: A Novel Surgical Approach for Safe Osteotomies in the Rehabilitation of an Atrophic Posterior Mandible: A Case Report.

A 56-year-old female patient with vertical atrophy of the right posterior mandible was treated adopting an interpositional bone block approach using a cancellous heterologous bone block. Osteotomies of the patient's mandible were performed with the help of dynamic computer-assisted surgery using virtual anatomical patient information obtained from a cone beam computed tomography (CBCT). The use of the dynamic computer-assisted surgery allowed authors to perform the horizontal osteotomy line as planned preoperatively on the CBCT virtual reconstruction, trying to minimize the risks of the inlay technique. No neurological complications were observed after surgery. The inlay technique could benefit from the aid of dynamic navigation technologies in posterior atrophic mandibles, increasing the reproducibility of the technique. A likely safer method for performing osteotomies with the "sandwich" technique in the posterior atrophic mandible is reported.

Minimally Invasive Fixed Rehabilitation of an Extremely Atrophic Posterior Mandible Using 4-mm Ultrashort Implants: A Case Report with a 7-Year Follow-up.

This case report describes the rehabilitation of an extremely atrophic posterior mandible using 4-mm ultrashort implants and reports clinical and radiographic outcomes 7 years after loading. The patient refused to undergo any other treatment, from the removable prosthesis to the reconstructive surgery, and asked for a fixed, minimally invasive solution in the shortest possible time. The residual bone height above the alveolar nerve was an average of about 5 mm, so it was decided to treat the patient with four 4-mm ultrashort implants. Within the limitations of this case report, this procedure appears successful at 7 years after loading in this specific case and could reduce invasiveness, rehabilitative times, and costs. However, longer follow-ups on a large number of patients coming from randomized controlled clinical trials are necessary before making more reliable recommendations.

Minimally Invasive Fixed Rehabilitation of a Totally Edentulous Severely Atrophic Mandible with 4-mm Ultrashort Immediately Loaded Implants: A Case Report.

This case report describes the minimally invasive full fixed rehabilitation of a totally edentulous severely atrophic mandible. The patient refused to undergo any other treatment, from the reconstructive surgery to the removable prosthesis, and asked for a fixed minimally invasive solution in the shortest possible time. Considering that the posterior mandibular bone was inadequate in height and that the interforaminal bone was only 4.3 to 5 mm in height, the patient received four 4-mm-ultrashort implants in the interforaminal area that were immediately loaded. Within all the limitations of this case report this procedure in this specific case appears successful through 2 years of loading.

One-Piece Implants with Smooth Concave Neck to Enhance Soft Tissue Development and Preserve Marginal Bone Levels: A Retrospective Study with 1- to 6-Year Follow-Up.

Novel one-piece implants with concave smooth neck have been introduced to promote the formation of a thick mucosal layer and preserve marginal bone. A retrospective study on 70 patients with 1- to 6-year follow-up was carried out. Cumulative survival rates were assessed. Variations of marginal bone level were measured on periapical radiographs as distance of the implant-abutment junction from the bone crest. Influence of different variables on treatment outcome was evaluated. Cumulative success rate after 6 years was 99.4 % at implant level and 98.6 % at patient level. Marginal bone level changed in a significant way over time. After 4 months, an increase of radiographic bone level of 0.173 ± 1.088 mm at implant level and 0.18 ± 1.019 mm at patient level was recorded. Mean marginal bone loss after 5 years was 0.573 ± 0.966 mm at implant level and 0.783 ± 1.213 mm at patient level. Age, sex, smoking habits, implant sites, implant lengths and diameters, prosthetic retentions, and timing of loading did not influence marginal bone remodeling in a statistically significant way. At 4-year follow-up partial restorations lost a mean of 0.96 mm of more marginal bone compared with single restorations. This difference was statistically significant.

Clinical Relevance of Bone Density Values from CT Related to Dental Implant Stability: A Retrospective Study.

PURPOSE: The majority of the techniques used to assess the primary implant stability are subjective and empirical and can be used during or after the surgery. The aim of this study is to evaluate the bone density prior to surgery, in order to give recommendations to the clinician about the best surgical technique and the type of implant which is needed. MATERIALS AND METHODS: A surgeon operated on 75 patients for 269 implants over the period 2010-2014. He required a CT to plan the surgery and he documented the type, the diameters, and the lengths of the implants, the insertion torque, and the ISQ values. At a later stage another clinician measured bone density and cortical thickness. We endeavoured to get the most accurate superimposition between the implants placed by the surgeon and those placed by the clinician. RESULTS: In maxilla ISQ showed a significant positive correlation with HU values detected for coronal-buccal (r = 0.302; p = 0.020) and middle-lingual (r = 0.295; p = 0.023). Torque showed a positive correlation with cortical bone thickness at the middle of the ridge (ρ = 0.196; p = 0.032). CONCLUSION: It is important to take into consideration the Hounsfield Units and the cortical thickness as predictive parameters during the preoperative assessment, with regard to the choice of the implant type as well as the surgical technique.

Displacement of a dental implant in the mandible body: an unusual case report.

PURPOSE: To present a case of a woman referred for the management of displacement of one implant in her right posterior mandible that had occurred three days previously. MATERIALS AND METHODS: After implant placement, the practitioner was no longer able to detect the implant and inserted a second one at the same site without taking a control radiograph. At the end of surgery, when a radiograph was finally taken, the first implant appeared displaced into the mandible body. The patient suffered total paresthesia on the right lower lip and chin. A flap was raised and bone osteotomies were performed on the lateral side of the mandible to create a rectangular cortical bone window that was removed. The implant was stuck by the second implant placed coronally, and only after unscrewing this second implant was it possible to remove the first one. RESULTS: After 18 months, the patient recovered full sensitivity. CONCLUSIONS: In cases of implant displacement, it is always recommended that appropriate radiographs are performed to visualise where the implants could have been displaced in order to avoid more serious consequences.

A Minimally Invasive Approach Using a 4-mm Implant Without Extraction of Impacted Maxillary Canine: Four-Year Postloading Results.

The aim of this case report was to suggest an alternative minimally invasive surgical approach to an impacted maxillary canine using a 4-mm-long implant for a fixed prosthetic rehabilitation, avoiding tooth extraction or surgically forced extrusion and exploiting the 6 mm of coronal bone availability. At 4 years postloading, the implant was healthy and well integrated with stable marginal bone levels. The 4-mm length of the implant reduced operative times, postsurgical morbidity, possible complications, and costs. Short implants might be an alternative to traditional, more invasive surgical procedures used in the rehabilitative treatment of impacted maxillary canines.

Conventional drills vs piezoelectric surgery preparation for placement of four immediately loaded zygomatic oncology implants in edentulous maxillae: results from 1-year split-mouth randomised controlled trial.

PURPOSE: To compare the outcome of site preparation for zygomatic oncology implants using conventional preparation with rotary drills or piezoelectric surgery with dedicated inserts for placing two zygomatic implants per zygoma according to a split-mouth design. MATERIALS AND METHODS: Twenty edentulous patients with severely atrophic maxillas not having sufficient bone volume for placing dental implants and less than 4 mm of bone height subantrally had their hemi-maxillas randomised according to a split-mouth design into implant site preparation with conventional rotational drills or piezoelectric surgery. Two zygomatic oncology implants (unthreaded coronal portion) were placed in each hemi-maxilla. Implants that achieved an insertion torque superior to 40 Ncm were immediately loaded with screw-retained metal reinforced acrylic provisional prostheses. Outcome measures were: prosthesis and implant failures, any complications, time to place the implants, presence of post-operative haematoma, and patient's preference by independent assessors. All patients were followed up to 1 year after loading. RESULTS: In two patients drills had also to be used at the piezoelectric surgery side to enable implant sites to be prepared. One implant for the conventional drill group did not achieve an insertion torque superior to 40 Ncm since it fractured the zygoma. No patients dropped out and two distal oncology implants failed in the same patient (one per group), who was not prosthetically rehabilitated. Six complications occurred at drilled sites and three at piezoelectric surgery sites (two patients had bilateral complications), the difference being not statistically significant (P (McNemar's test) = 0.375; odds ratio = 4.00; 95% CI of odds ratio: 0.45 to 35.79). Implant placement with convention drills took on average 14.35 ±â€…1.76 min and with piezoelectric surgery 23.50 ±â€…2.26 min, implant placement time being significantly shorter with conventional drilling (difference = 9.15 ±â€…1.69 min; 95%CI: 8.36 to 9.94 min; P < 0.001). Post-operative haematomas were more frequent at drilled sites (P = 0.001), and 16 patients found both techniques equally acceptable, while four preferred piezoelectric surgery (P = 0.125). CONCLUSIONS: Both drilling techniques achieved similar clinical results, but conventional drilling required 9 min less and could be used in all instances, although it was more aggressive. These results may be system-dependent, therefore they cannot be generalised to other zygomatic systems with confidence. Conflict-of-interest statement: This study was partially supported by Southern Implants (Irene, South Africa), the manufacturer of the zygomatic implants and the conventional drills evaluated in this study. However, data property belonged to the authors and by no means did the manufacturer interfere with the conduct of the trial or the publication of its results. Drs Felice and Pistilli developed the piezoelectric surgery zygomatic insert used in the present study.

Four mm-long versus longer implants in augmented bone in atrophic posterior jaws: 4-month post-loading results from a multicentre randomised controlled trial.

PURPOSE: To evaluate whether 4-mm long dental implants could be an alternative to augmentation with equine bone blocks and the placement of at least 10-mm long implants in atrophic posterior jaws. MATERIALS AND METHODS: Forty patients with atrophic posterior (premolar and molar areas) mandibles having 5 to 6 mm bone height above the mandibular canal and 40 patients with atrophic maxillae having 4 to 5 mm below the maxillary sinus, were randomised according to a parallel group design to receive one to three 4.0 mm-long implants or one to three implants, which were at least 10 mm long, in augmented bone at two centres. All implants had a diameter of 4.0 or 4.5 mm. Mandibles were vertically augmented with interpositional equine bone blocks and resorbable barriers. Implants were placed 4 months after interpositional grafting. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers, and implants were placed simultaneously. Implants were not submerged and were loaded after 4 months with provisional prostheses. Four months later, screw-retained reinforced acrylic restorations were delivered, and then replaced after 4 months by definitive screw-retained metal-composite prostheses. Patients were followed up to 4-months post-loading. Outcome measures included prosthesis and implant failures, any complication and peri-implant marginal bone level changes. RESULTS: No patient dropped out. In six augmented mandibles (30%), it was not possible to place implants which were at least 10.0-mm long, therefore shorter implants had to be placed instead. In particular, one mandible fractured and the patient did not want to go ahead with the treatment. One implant of the patient with the mandible fracture from the augmented group failed versus two 4.0 mm implants in two patients from the short implant group. In the maxillae, three short implants failed in two patients versus five long implants in three patients (two long implants and one short implant dropped into the maxillary sinus). Two prostheses on short implants (one mandibular and one maxillary) were placed at a later stage because of implant failures versus four prostheses (one mandibular and three maxillary) at augmented sites. In particular, three patients of the augmented group (one mandible and two maxillary) were not prosthetically rehabilitated. There were no statistically significant differences in implant failures (P (chi-square test) = 1.000; difference in proportion = 0; 95% Cl: -0.13 to 0.13 or prostheses failures (P (chi-square test) = 0.399; difference in proportion = 0.05; 95% Cl: -0.06 to 0.16). At mandibular sites, nine augmented patients were affected by complications versus one patient treated with short implants (P (chi-square test) = 0.003; difference in proportion = 0.40; 95% Cl: 0.16 to 0.64), with the difference being statistically significant. No significant differences were found for the maxillae: eight sinus lift patients versus three patients rehabilitated with maxillary short implants were affected by complications (P (chi-square test) = 0.077; difference in proportion = 0.25; 95% Cl: -0.02 to 0.52). Patients with mandibular short implants lost on average 0.40 mm of peri-implant bone at 4 months and patients with 10 mm or longer mandibular implants lost 0.52 mm. Patients with short maxillary implants lost on average 0.48 mm peri-implant bone at 4 months and patients with 10 mm or longer maxillary implants lost 0.50 mm. The difference was statistically significant in the mandibles (mean difference: -0.12 mm, 95% CI: -0.20 to -0.04, P (ANCOVA) = 0.006), but not in the maxillae (mean difference: -0.02 mm, 95% CI: -0.10 to 0.07, P (ANCOVA) = 0.711). CONCLUSIONS: Four months after loading 4.0 mm-long implants achieved similar results, if not better, than longer implants in augmented jaws, but were affected by fewer complications. Short implants might be a preferable choice to bone augmentation, especially in mandibles, since the treatment is less invasive, faster, cheaper, and associated with less morbidity; however, 5- to 10-year post-loading data is necessary before making reliable recommendations. Conflict-of-interest statement: Global-D (Brignais, France) partially supported this trial and donated the implants and prosthetic components; however, data property belonged to the authors and by no means did Global-D interfere with the conduct of the trial or the publication of the results.

Inferior alveolar nerve laceration after implant site preparation: A case report.

PURPOSE: The aim of this article is to present a referred clinical case of an inferior alveolar nerve laceration during the insertion of a dental implant in the mandible, that came to our attention after the injury. MATERIALS AND METHODS: A 71-year-old female was treated by a colleague in order to be rehabilitated with a fixed implant-supported prosthesis for her missing teeth in positions 44, 45 and 46. After implant site osteotomy in region 46, the speed of the surgical motor was not changed; as a consequence, the implant was inserted at 1200 rpm and intruded into the mandibular canal, causing the laceration of the neurovascular bundle. RESULTS: During the first 2 weeks after surgery the patient complained of paresthesia in the mental and lower lip area, with labial ptosis and drooling. After 14 days, the paresthesia reduced and mucosal and gingival normosensitivity was detected; however, the patient complained about hyperesthesia of the lower inside lip. After 21 days, the lower lip tone and function were almost completely restored and the paresthesia was further reduced, however the hyperesthesia persisted. CONCLUSIONS: It is extremely important to pay attention to preventing neurological complications through proper preoperative planning, careful execution of the surgical techniques and correct management of instruments and motor speed settings. The latter procedure should be double-checked by both the operator and the assistant.

Short implants versus longer implants in vertically augmented posterior mandibles: a randomised controlled trial with 5-year after loading follow-up.

OBJECTIVES: To evaluate whether 6.6-mm long implants could be a suitable alternative to longer implants placed in vertically augmented atrophic posterior mandibles. MATERIALS AND METHODS: Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on CT scans above the mandibular canal were randomised according to a parallel group design. They were either to receive 1 to 3 submerged 6.6-mm long implants or 9.6 mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with interpositional anorganic bovine bone blocks covered by resorbable barriers. Grafts were left to heal for 5 months before implant placement. Four months after provisional acrylic prostheses were delivered, they were replaced, after 4 months, by definitive metal-ceramic prostheses. Outcome measures were: prosthesis and implant failures; complications; and radiographic peri-implant marginal bone level changes. All patients were followed up to 5 years after loading. RESULTS: Five years after loading, 8 patients dropped out: 3 from the short implant group and 5 from the augmented group. The augmentation procedure failed in 2 patients and only 6.6-mm long implants could be inserted. There were no statistically significant differences for prosthesis and implant failures. Five prostheses failed in 4 patients of the short implant group versus 5 prostheses in 5 patients in the augmented group (Fishers exact test P = 1.0; difference in proportions = 0.07; 95% CI -0.29 to 0.43). Five short implants failed in 3 patients versus 3 long implants in 3 patients (Fishers exact test P = 1.00 difference in proportions = 0.00; 95% CI -0.43 to 0.43). There were statistically more complications in augmented patients (25 complications in 21 augmented patients versus 6 complications in 6 patients of the short implant group) (Fishers exact test P < 0.0001; difference in proportions = 0.60; 95% CI 0.38, 0.82). Both groups gradually lost peri-implant bone in a statistically significant way. Five years after loading, short implant group patients lost an average of 1.49 mm peri-implant bone compared with 2.34 mm in the augmented group. Short implants experienced statistically significantly less bone loss (0.82 mm, 95% CI 0.48; 1.16, P < 0.0001) than long implants. CONCLUSIONS: When residual bone height over the mandibular canal is between 7 to 8 mm, 6.6 mm short implants could be an interesting alternative to vertical augmentation in posterior atrophic mandibles since the treatment is faster, cheaper and associated with less morbidity. Longer follow-ups may still be needed to confirm these results, however the medium-term prognosis (5 years after loading) of short implants is at least as good as those of longer implants placed vertically in augmented mandibles.

Three-year results from a randomised controlled trial comparing prostheses supported by 5-mm long implants or by longer implants in augmented bone in posterior atrophic edentulous jaws.

PURPOSE: To evaluate whether 5-mm short dental implants could be an alternative to augmentation with anorganic bovine bone and placement of at least 10-mm long implants in posterior atrophic jaws. MATERIALS AND METHODS: Fifteen patients with bilateral atrophic mandibles (5 mm to 7 mm bone height above the mandibular canal) and 15 patients with bilateral atrophic maxillae (4 mm to 6 mm bone height below the maxillary sinus), and bone thickness of at least 8 mm, were randomised according to a split-mouth design to receive one to three 5-mm short implants or at least 10-mm long implants in augmented bone. Mandibles were vertically augmented with interpositional bone blocks and maxillary sinuses with particulated bone via a lateral window. Implants were placed after 4 months, submerged and loaded, after another 4 months, with provisional prostheses. Four months later, definitive provisionally cemented prostheses were delivered. Outcome measures were: prosthesis and implant failures; any complication and peri-implant marginal bone level changes. RESULTS: In five augmented mandibles, the planned 10-mm long implants could not be placed and shorter implants (7 mm and 8.5 mm) had to be used instead. Three years after loading, two patients, one treated in the mandible and one in the maxilla, dropped out. Three prostheses (1 mandibular and 2 maxillary) failed in the short implant group versus none in the long implant group. In mandibles, one long implant failed versus two short implants in 1 patient. In maxillae, one long implant failed versus three short implants in 2 patients. There were no statistically significant differences in the failures. Eight patients had 13 complications at short implants (1 patient accounted for 6 complications) and 11 patients had 13 complications at long implants. There were no statistically significant differences in complications (P = 0.63, difference = 0.10, 95% CI from -0.22 to 0.42). Three years after loading, patients with mandibular implants lost on average 1.44 mm at short implants and 1.63 mm at long implants of peri-implant marginal bone. This difference was not statistically significant (difference = 0.24 mm; 95% CI -0.01, 0.49 P = 0.059). In maxillae, patients lost on average 1.02 mm at short implants and 1.54 mm at long implants. This difference was statistically significant (difference = 0.41 mm; 95% CI 0.21, 0.60, P = 0.001). CONCLUSIONS: Three years after loading, 5-mm short implants achieved similar results as longer implants in augmented bone. Short implants might be a preferable choice to vertical bone augmentation, especially in mandibles, since the treatment is faster and cheaper, however there are still insufficient data on the long-term prognosis of short implants.

Rehabilitation of the atrophic posterior mandible with short (4-mm) implants: a case report.

This case report describes a successful implant-prosthetic rehabilitation of an atrophic posterior mandible with 4-mm-long implants. The patient refused to undergo any reconstructive surgery, and because the available bone up to the inferior alveolar nerve was only 5 mm or less, the patient received four implants of 4-mm length. Four months after implant placement, a provisional prosthesis was put in place; after another 4 months, this was then in turn replaced with a definitive prosthesis. The use of such short implants allows a fixed prosthetic solution without the need for vertically augmenting the mandibular bone. This procedure considerably reduces intra- and postoperative patient discomfort compared with reconstructive surgery for the placement of longer implants. The follow-up time was 1 year after implant loading.

Cosci versus Summers technique for crestal sinus lift: 3-year results from a randomised controlled trial.

PURPOSE: To compare the effectiveness of two different techniques to lift the maxillary sinus via a crestal approach: the Summers versus the Cosci technique. MATERIALS AND METHODS: Fifteen partially edentulous patients missing bilaterally maxillary molars and/ or premolars, having 4 to 7 mm of residual crestal height and at least 5 mm thickness below the maxillary sinuses measured on CT scans, were randomised to have implants placed in sinuses crestally lifted according to the Cosci or the Summers techniques, with bone substitutes according to a split-mouth design. Implants were left to heal submerged for 6 months. Implants were loaded with acrylic provisional crowns/prostheses. Screw-retained definitive metal-ceramic prostheses were delivered 4 months after provisional loading. Outcome measures were: prosthesis and implant failures; any complications; operation time; operator preference; patient preference and peri-implant marginal bone level changes assessed by a blinded outcome assessor. All patients were followed to 3 years after implant loading. RESULTS: Nineteen study implants were placed according to each technique. Three years after loading, 3 patients dropped out and no implant failed. No discomfort/complications occurred at sites treated with the Cosci technique, whereas 12 patients reported discomfort during the augmentation procedure at the side treated with the Summers technique; this was statistically significant (P = 0.0005). In one of these patients, a perforation of the sinus membrane occurred. Postoperatively, headache was reported by 9 patients and swelling occurred in 3 of these patients at the Summers treated sides. Statistically significant less time (9.7 mins, SD = 4.0, P < 0.001, 95% CI -11.9 to -7.5) was required to place implants according to the Cosci technique (33 versus 24 mins on average). The 2 operators and 14 out of 15 patients preferred the Cosci technique 1 month after surgery (P = 0.001), and 1 year after surgery (13 out of 15 patients, P = 0.007). The ceramic layer of one prosthesis of the Summers' group and one abutment screw of the Cosci's group loosened between 1 to 3 years post-loading. After 3 years, implants inserted according to the Cosci technique lost 1.39 mm of peri-implant bone versus 1.54 mm for the implants placed with the Summers technique. There were no statistically significant differences for marginal bone level changes between the two groups (difference 0.15 mm, 95% CI -0.11 to 0.41, P = 0.24). CONCLUSIONS: Both crestal sinus lift techniques produced successful results over a 3-year follow-up period, but the Cosci technique required less surgical time, determined less intra- and postoperative morbidity and was preferred by patients. Conflict of interest statement: This was an investigator-initiated trial, however the trial was partially supported by Zimmer Dental Italy, Vittorio Veneto (TV), Italy. One of the authors (Dr Cosci), who treated 8 patients in this study, is the inventor of the Cosci technique and his partipation was a prerequisite of the sponsor to support the trial.