A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

Human histologic evaluation of the use of the dental putty for bone formation in the maxillary sinus: case series

A proof-of-principle study was conducted to assess the safety and efficacy of dental putty as an alternative sinus augmentation biomaterial. Six healthy patients requiring a total of 10 sinus augmentations received sinus augmentations. All patients volunteered and signed an informed consent based on the Helsinki declaration of 1975, as revised in 2000. The sinus augmentation was performed under local anesthesia with a mucoperiosteal flap elevated to expose the buccal wall of the maxillary sinus. The space was then filled with the dental putty in several increments, and the window was covered with an absorbable collagen membrane. Biopsies were harvested from all 10 treated sinuses using a 3-mm trephine bur at the time of implant placement at either 6 or at 9 months after sinus augmentation. All patients completed the study without complications, except for 1 patient who reported fistulas at 1 and 2 months after the surgery. Clinical reentry revealed that regenerated bone on the osteotomy site was soft and immature. The ground sections of the biopsied cores revealed minimum amounts of trabeculation surrounded by an abundant array of irregular-shaped residual alloplastic particles embedded in loose connective tissue. The present study's findings revealed inadequate bone formation, although the material appears to be bioinert as there is no elicitation of inflammatory response.

Maxillary sinus floor elevation and grafting with deproteinized bovine bone mineral: a clinical and histomorphometric study

OBJECTIVES

This study evaluated the histomorphometric and clinical outcomes of maxillary sinus floor elevation using deproteinized bovine bone mineral (DBBM).

MATERIAL AND METHODS

Maxillary sinuses with a residual vertical height of <5 mm were augmented with DBBM alone before implant placement 9 months later. At the time of implant surgery, trephine samples were removed and histological and histomorphometric analyses were performed to examine the percentage of bone and residual graft using point counting and software-aided analysis. Patients were recalled for clinical and radiographic examination up to 3 years later.

RESULTS

Twenty-five patient specimens were analysed. The percentages of regenerated bone and residual graft material were 19% and 40%, respectively. Software-aided analysis was comparable to point counting. Twelve patients attended for clinical follow-up. Implants placed into this regenerated bone exhibited success and survival rates of 100% after an average follow-up of 3 years. The average vertical height gained was 7.9 mm.

CONCLUSIONS

The use of DBBM alone in maxillary sinus floor elevation is a predictable method to gain vertical bone height in the posterior maxilla.

Bone marrow concentrate and bovine bone mineral for sinus floor augmentation: a controlled, randomized, single-blinded clinical and histological trial--per-protocol analysis

PURPOSE

The purpose of this work was to evaluate the potential of substituting autogenous bone (AB) by bone marrow aspirate concentrate (BMAC). Both AB and BMAC were tested in combination with a bovine bone mineral (BBM) for their ability of new bone formation (NBF) in a multicentric, randomized, controlled, clinical and histological noninferiority trial.

MATERIALS AND METHODS

Forty-five severely atrophied maxillary sinus from 26 patients were evaluated in a partial cross-over design. As test arm, 34 sinus of 25 patients were augmented with BBM and BMAC containing mesenchymal stem cells. Eleven control sinus from 11 patients were augmented with a mixture of 70% BBM and 30% AB. Biopsies were obtained after a 3-4-month healing period at time of implant placement and histomorphometrically analyzed for NBF.

RESULTS

NBF was 14.3%±1.8% for the control and nonsignificantly lower (12.6%±1.7%) for the test (90% confidence interval: -4.6 to 1.2). Values for BBM (31.3%±2.7%) were significantly higher for the test compared with control (19.3%±2.5%) (p<0.0001). Nonmineralized tissue was lower by 3.3% in the test compared with control (57.6%; p=0.137).

CONCLUSIONS

NBF after 3-4 months is equivalent in sinus, augmented with BMAC and BBM or a mixture of AB and BBM. This technique could be an alternative for using autografts to stimulate bone formation.

Are gingival phenotype, residual ridge height, and membrane thickness critical for the perforation of maxillary sinus?

BACKGROUND

Sinus membrane perforation is the most common complication of the sinus-augmentation procedure. Anatomic factors have been implicated in the risk of sinus membrane perforation (SMP) during sinus-lift surgery. However, there are no reports on the relationships among gingival phenotype (GP), residual ridge height (RRH), membrane thickness (MT), and perforation rate of the maxillary sinus. Therefore, the aim of this clinical study is to determine the associations among GP, RRH, MT, and SMP rate.

METHODS

Forty-four patients (64 sinus-lift procedures) were included in the study. Preoperative computed tomography scanning was performed to radiographically evaluate GP, RRH, and MT. The smallest RRH, highest MT, and gingival thickness values were recorded. These values were classified as follows: RRH, < or >3.5 mm; MT, < or >1 mm; and GP, <1.5 or >2 mm. Sinus-lift surgery was performed with a lateral window approach, and SMPs were detected at 11 sinus sites. Perforation size and locations were recorded, and the perforations were repaired with collagen membrane. One hundred seventy-six implants were placed immediately after augmentation procedure.

RESULTS

Strong correlations of GP with RRH (r = 0.722, P = 0.001) and MT (r = 0.702, P = 0.001) were noted. Moderate correlations were found between RRH and MT (r = 0.596, P = 0.001) and between MT and SMP (r = 0.417, P = 0.001). Furthermore, mild correlations of SMP with RRH (r = 0.290, P = 0.020) and GP (r = 0.248, P = 0.04) were established. Four implants were lost, but no significant difference was found between implant failure and SMP.

CONCLUSION

Within the limits of the study, it may be suggested that GP, RRH, and MT may be important factors for sinus perforation.

Case series of maxillary sinus augmentation with biphasic calcium phosphate: a clinical and radiographic study

Purpose

The aim of this study was to evaluate 3.5 years-cumulative survival rate of implants placed on augmented sinus using Osteon, a bone graft material, and to assess the height of the grafted material through radiographic evaluation.

Methods

Twenty patients were treated with maxillary sinus augmentation and 45 implant fixtures were installed simultaneously or after 6 months healing period. The height of the augmented sinus and the loss of marginal bone were measured by panoramic and intraoral radiographs immediately after augmentation and up to 42 months (mean, 19.4 months) subsequently. Changes in the height of the sinus graft material were calculated radiographically.

Results

The cumulative survival rate was 95.56% in all 45 implants. Additionally, normal healing process without any complication was observed in all patients. The original sinus height was mean 4.3 mm and the augmented sinus height was mean 13.4 mm after the surgery. The mean marginal bone loss till 42 months was 0.52±0.56 mm. The reduced height of Osteon was 0.83±0.38 mm and it did not show significant correlation with the follow up periods (P=0.102). There were no statistically significant differences in reduced height of Osteon according to the simultaneous/delayed implantation (P=0.299) and particle size of Osteon (P=0.644).

Conclusions

It can be suggested that Osteon may have predictable result when it was used as a grafting material for sinus floor augmentation.

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

OBJECTIVES

The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation.

METHODS

In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non-decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated.

RESULTS

Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively).

CONCLUSION

Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus.

Evaluation of an anorganic bovine-derived mineral with P-15 hydrogel bone graft: preliminary study in a rabbit cranial bone model

OBJECTIVES

The present investigation aimed to assess the bone-regenerative potential of two formulations of anorganic bovine-derived mineral bound to a P-15 (ABM/P-15) bone graft - the particulate and the hydrogel forms - in a delayed healing rabbit cranial defect model.

MATERIAL AND METHODS

Ten adult male New Zealand White rabbits were used to create two 8 mm transcortical cranial defects per rabbit and each one received randomly the test material (ABM/P-15 carboxymethyl cellulose (CMC)-hydrogel graft), the standard control material (ABM/P-15 particulate graft) or remained empty as a negative control. The defects were allowed to heal for 2 and 4 weeks. Qualitative and quantitative histological outcomes were assessed on undecalcified sections.

RESULTS

In the defects grafted with the test material, at both time points, there was a marked random migration of the bone substitute particles. As a consequence, the space maintenance provision was lost and new bone formation was reduced compared with the control particulate graft material. The histomorphometric analysis showed that the control material attained better results, with an average of 13.8 ± 1.9% and 18.2 ± 4.4% of new bone at 2 and 4 weeks, compared with 8.5 ± 2.4% and 13 ± 2.9% for the test material. These differences were significant at 2 weeks (P ≤ 0.05), but not at 4 weeks (P>0.05). Additionally, there was a significant difference in the total area of mineralized tissue (new bone plus particles), favoring the standard control over the test material: 43.2 ± 14.4% vs. 14.2 ± 5.3% at 2 weeks and 56.9 ± 4.2% vs. 24.2 ± 9.6% at 4 weeks, respectively.

CONCLUSIONS

The test ABM/P-15 CMC-hydrogel graft material behaved in this animal model by migration of the graft particles, what determined an unpredictable osseoconduction and, consequently, a decreased quality and quantity of bone regeneration as compared with the osseopromotive behavior exhibited by the standard particulate form of the ABM/P-15 control graft. It is therefore suggested to restrain the application of the hydrogel graft form in non-contained anatomical bone defects.

Effect of autologous growth factors in maxillary sinus augmentation: a systematic review

PURPOSE

The aim of the present study was to systematically evaluate the effect of autogenous platelet concentrates on the clinical and histomorphometric outcomes of maxillary sinus augmentation.

MATERIALS AND METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. Furthermore, a hand searching of the relevant journals and of the bibliographies of reviews was performed. Prospective comparative clinical studies were included. Implant survival and histomorphometric outcomes were evaluated.

RESULTS

Twelve studies were included. Four hundred forty-five sinus floor augmentation procedures were considered. No difference in implant survival was reported between test and control groups. Six studies reported a beneficial effect of platelet concentrates based on histomorphometric outcomes, while another six studies found no significant effect. A large heterogeneity was found regarding study design, surgical techniques, graft materials, clinical and histomorphometric outcome variables, and methods for preparing platelet concentrates. Favorable effects on soft tissue healing and postoperative discomfort reduction were often reported but not quantified.

CONCLUSIONS

A clear advantage of platelet concentrates could not be evidenced. Standardization in the experimental design is needed in order to detect the true effect of platelet concentrates in maxillary sinus augmentation procedure, especially regarding postoperative quality of life.

Mandibular bone harvesting for alveolar reconstruction and implant placement: subjective and objective cross-sectional evaluation of donor and recipient site up to 4 years

AIM

To evaluate the long-term morbidity of intraoral bone harvesting from two different donor sites (mandibular symphysis or ramus) for bone augmentation procedures before or at the time of implant placement and to evaluate the success and the survival rates of implants placed in sites augmented with mandibular bone.

METHODS

Seventy-eight patients who received mandibular bone grafts were recalled after 18-42 months follow-up (mean 29 months). The group consisted of 36 men and 42 women aged between 18 and 68 years old at the moment of augmentation surgery. Vitality of teeth adjacent to the harvesting sites was investigated. Soft tissue superficial sensory function was assessed by the Pointed-Blunt Test and the Two-Point-Discrimination Test. Implant health status was assessed measuring peri-implant probing depth and bleeding on probing. Implant survival and success rates were also calculated. In order to evaluate patients' perception of the morbidity of the procedures, the patients were asked to answer several questions by means of visual analogue scales (VAS).

RESULTS

Only two teeth (out of 282) in the chin harvesting group needed root canal treatment after surgery. A higher frequency of minor temporary and permanent sensorial disturbances was found in the group of patients who received chin harvesting procedures (2.3% vs. 13%P=0.03), while pain during chewing and bleeding were more frequently recorded after ramus harvesting (9.8% vs. 0%P=0.03). No permanent anesthesia of any region of the skin was reported. Implants' survival and success rate were comparable to implants placed in bone reconstructed with other techniques and were not influenced by the choice of the donor site. Patient's perception regarding the morbidity of the procedures was very low and did not differ between ramus and chin harvesting groups (mean VAS scores <4).

CONCLUSION

The present cross-sectional retrospective study demonstrated the safety of mandibular grafts that reported excellent results in terms of implant success and survival rates with minor complications regarding the donor site area. When the chin was chosen as donor site, minor sensorial disturbances of mucosa and teeth were recorded. The majority of these disturbances were temporary; only few of them were permanent but still had no impact on patient's life.

Effect of LCD monitor type and observer experience on diagnostic performance in soft-copy interpretations of the maxillary sinus on panoramic radiographs

Purpose

The aim of this study was to evaluate the effect of liquid crystal display (LCD) monitor type and observer experience on the diagnostic performance in soft-copy interpretations of maxillary sinus inflammatory lesions on panoramic radiographs.

Materials and Methods

Ninety maxillary sinuses on panoramic images were grouped into negative and positive groups according to the presence of inflammatory lesions, using CT for confirmation. Monochrome and color LCDs were used. Six observers participated and ROC analysis was performed to evaluate the diagnostic performance. The reading time, fatigue score, and inter-/intra-observer agreements were assessed.

Results

The interpretation of maxillary sinus inflammatory lesions was affected by the LCD monitor type used and by the experience of the observer. The reading time was not significantly different, however the fatigue score was significantly different between two LCD monitors. Inter-observer agreement was relatively good in experienced observers, while the intra-observer agreement for all observers was good with monochrome LCD but not with color LCD.

Conclusion

The less experienced observers showed lowered diagnostic ability with a general color LCD.

An animal model for sinus floor elevation with great elevation heights. Macroscopic, microscopic, radiological and micro-CT analysis: ex vivo

OBJECTIVES

Different animal models are used for research and training concerning sinus floor elevation. However, there is little information regarding an animal model for elevation heights of approximately 10 mm. The aim of this study was to explore the anatomical aspects of the maxillary sinus of adult pigs and to investigate the suitability of this animal as a model for sinus floor elevation training and research with great elevation heights.

MATERIAL AND METHODS

Thirty-four bisected heads of adult domestic pigs were examined 6 h postmortem. Direct sinus floor elevation was performed with an elevation height of 10 mm. Localization, diameters, volume and septa of the maxillary sinus were recorded on lateral X-rays and macroscopically. The thickness and structure of the maxillary sinus were investigated microscopically. The osseous microstructure of the lateral sinus wall was assessed microscopically and via micro-CT.

RESULTS

The maxillary sinus of the adult pig exhibits an average length of 51±6.2 mm, a height of 31±4.1 mm, a width of 19±1.6 mm and a volume of 31±7.6 cm(3) . At least one septum could be observed on the floor of each sinus. The mucosal thickness amounted to a mean of 1692±138 μm, and the lateral bony wall of the sinus to a mean of 3±0.3 mm. A laceration of the Schneiderian membrane occurred in 25% during the elevation process.

CONCLUSION

The maxillary sinus of adult domestic pigs is a suitable model for sinus floor elevation training and research with greater elevation heights of up to 10 mm.

Incomplete bone formation after sinus augmentation: A case report on radiological findings by computerized tomography at follow-up

Purpose

The aim of this case report is to present a case of incomplete bone formation after sinus augmentation.

Methods

A patient having alveolar bone resorption of the maxillary posterior edentulous region and advanced pneumatization of the maxillary sinus was treated with sinus elevation using deproteinized bovine bone in the Department of Periodontology, Kyung Hee University School of Dentistry and re-evaluated with computed tomography (CT) follow-up.

Results

Even though there were no significant findings or abnormal radiolucency on the panoramic radiograph, incomplete bone formation in the central portion of the augmented sinus was found fortuitously in the CT scan. The CT scan revealed peri-implant radiolucency in the apical portion of the implant placed in the augmented maxillary sinus. Nevertheless, the dental implants placed in the grafted sinus still functioned well at over 15 months follow-up.

Conclusions

The result of this case suggests that patients who received maxillary sinus augmentation may experience incomplete bone formation. It is possible that 1) osteoconductive graft material with poor osteogenic potential, 2) overpacking of graft material that restricts the blood supply, and 3) bone microbial contamination may cause the appearance of incomplete bone formation after sinus augmentation. Further studies are needed to elucidate the mechanism of this unexpected result and care must be taken to prevent it.

Maxillary sinus vascular anatomy and its relation to sinus lift surgery

OBJECTIVES

To investigate the prevalence, location, size and course of the anastomosis between the dental branch of the posterior superior alveolar artery (PSAA), known as alveolar antral artery (AAA), and the infraorbital artery (IOA).

MATERIAL AND METHODS

The first part of the study was performed on 30 maxillary sinuses deriving from 15 human cadaver heads. In order to visualize such anastomosis, the vascular network afferent to the sinus was injected with liquid latex mixed with green India ink through the external carotid artery. The second part of the study consisted of 100 CT scans from patients scheduled for sinus lift surgery.

RESULTS

An anastomosis between the AAA and the IOA was found by dissection in the context of the sinus anterolateral wall in 100% of cases, while a well-defined bony canal was detected radiographically in 94 out of 200 sinuses (47% of cases). The mean vertical distance from the lowest point of this bony canal to the alveolar crest was 11.25 ± 2.99 mm (SD) in maxillae examined by CT. The canal diameter was <1 mm in 55.3% of cases, 1-2 mm in 40.4% of cases and 2-3 mm in 4.3% of cases. In 100% of cases, the AAA was found to be partially intra-osseous, that is between the Schneiderian membrane and the lateral bony wall of the sinus, in the area selected for sinus antrostomy.

CONCLUSIONS

A sound knowledge of the maxillary sinus vascular anatomy and its careful analysis by CT scan is essential to prevent complications during surgical interventions involving this region.

Implant survival after sinus elevation with Straumann(®) BoneCeramic in clinical practice: ad-interim results of a prospective study at a 15-month follow-up

OBJECTIVES

Elevation of the sinus floor with Straumann(®) BoneCeramic gave promising results in some recent clinical studies. However, no study has evaluated the long-term survival of implants after this surgical procedure. We are conducting a prospective, observational study to evaluate the long-term implant survival after this surgical procedure in clinical practice. We present here an ad-interim report of this study, including only patients with ≥12-month follow-up after implant placement.

METHODS

This prospective cohort study will last until a follow-up of 5 years will be achieved in at least 50 patients. Inclusion criteria are: age ≥18 years; presence of a maxillary partial unilateral or bilateral edentulism involving the premolar/molar areas; elective rehabilitation with oral implants; and physical capability to tolerate conventional surgical and restorative procedures. Patients are treated according to the two-stage technique and the preparation is filled with Straumann(®) BoneCeramic. Implant survival is evaluated every 3 months for the first 2 years, and then every 6 months up to 5 years.

RESULTS

Fifteen patients are considered in this ad-interim analysis. Mean follow-up was 14.9 ± 3.1 (range: 6-18 months). In total, three implants failed, in one single patient, 6 months after insertion. The cumulative implant survival rate was 92.5% (95% confidence interval: 83.0-100%).

CONCLUSIONS

This ad-interim analysis suggests that the elevation of the sinus floor with Straumann(®) BoneCeramic may be an effective clinical option over >1-year follow-up. A longer term follow-up will allow a deeper characterization of these preliminary findings.

Clinical and histologic outcomes after the use of a novel allograft for maxillary sinus augmentation: a case series

PURPOSE

To document the clinical and histologic outcomes of sinus augmentation using a novel allogenic bone substitute as a sole grafting material.

MATERIALS

Patients in need of sinus augmentation before implant placement were recruited for this study. Sinus augmentation procedures were performed following a lateral approach, using a freeze-dried allograft as the only grafting material. Patients were followed up postoperatively for 6 months. Plaque score, wound healing, and patient discomfort were recorded at each follow-up visit. Implants were placed between 6 and 7 months after sinus augmentation and restored 6 months later. Bone core biopsy specimens were harvested at the time of implant placement and processed for histologic and histomorphometrical analysis. Vital bone, remaining allograft (RA) particles, and nonmineralized tissue percentages were assessed on each sample. Results were expressed as mean percentages with SD.

RESULTS

Of the 23 sinus patients, 20 patients underwent sinus augmentation surgery. All patients had satisfactory postoperative healing in the absence of complications. A total of 39 implants were placed. One implant failed and was replaced 3 months later. Histologic analysis revealed the presence of well-organized lamellar bone, in direct contact with RA particles. Mean vital bone was 23.02 +/- 19.11%, mean RA was 22.25 +/- 20.30%, and average nonmineralized tissue was 54.73 +/- 13.51%.

CONCLUSION

Clinical and histologic findings support the suitability of an allograft consisting of a combination of cortical and cancellous chips for sinus augmentation procedures.

Histomorphometric analysis after maxillary sinus floor augmentation using cancellous bone-block allograft

BACKGROUND

Cancellous bone-block allografts may contribute to improved initial implant stability during sinus augmentation in cases with posterior atrophic maxillary ridge height < or =4 mm. The present study histologically and histomorphometrically evaluates the application of cancellous bone-block allografts for maxillary sinus-floor augmentation.

METHODS

Thirty-one consecutive patients, 16 females and 15 males (age range, 25 to 65 years; mean age: 54 +/- 9 years) underwent sinus augmentation with simultaneous implant placement with cancellous bone-block allografts. After 9 months, a second-stage surgery was performed. The previous window location was determined. A cylindrical sample core was collected. All specimens were prepared for histologic and histomorphometric examinations.

RESULTS

Seventy-two of 76 implants were clinically osseointegrated (94.7%). All patients received a fixed implant-supported prosthesis. The mean t values of newly formed bone, residual cancellous bone-block allograft, marrow and connective tissue were 26.1% +/- 15% (range: 10% to 58%); 24.7% +/- 19.4% (range: 0.6% to 71%), and 49.2% +/- 20.4% (range: 14.9% to 78.9%), respectively. No statistically significant histomorphometric differences regarding newly formed bone were found between genders (27.02% in males versus 25.68% in females; P = 0.446), ages (29.82% in subjects < or =40 years old versus 24.43% in subjects >40 years old; P = 0.293), presence of membrane perforations (25.5% in non-perforated sinuses versus 27.3% in perforated sinuses; P = 0.427), and residual alveolar bone height (25.85% for residual alveolar bone height <2 mm versus 26.48% for residual alveolar bone height of 2 to 4 mm; P = 0.473).

CONCLUSION

The cancellous bone-block allograft is biocompatible and osteoconductive and permits new bone formation in sinus augmentations with simultaneous implant-placement procedures in extremely atrophic posterior maxillae.

Piezoelectric-assisted osteotome-mediated sinus floor elevation: an innovative approach

Sinus floor elevation can be done by lateral maxillary approach or crestal approach by osteotome techniques as a function of residual bone height. The osteotome technique has been developed for minor sinus floor elevation. This is a method with relatively high predictability but is technically demanding. During the past decade, different osteotome-mediated sinus floor elevation techniques have been developed to augment the sinus for predictable implant placement. All these methods aim to access a better, predictable sinus augmentation with low morbidity. Some of these techniques require special equipment or materials, complicated procedure, and a long learning curve. This article describes an innovative approach to sinus augmentation, namely, piezoelectric-assisted osteotome-mediated sinus floor elevation. This method uses a newly designed piezoelectric tip, which can perform sinus floor osteotomy in a simple and atraumatic way. This approach has the greatest advantages of good tactile sense in osteotomy, least perforation, patient comfort with the least and lightest malleting, and shortened surgery. This method may be the most favorable osteotome technique in the future.

Transcrestal sinus floor elevation: a retrospective study of 46 patients up to 16 years

BACKGROUND

The aim of this study was to evaluate the clinical outcomes and radiographic data of transcrestal sinus floor elevation (TSFE) of residual alveolar bone ≤3 mm.

METHODS

Forty-six patients, edentulous in one or both maxillary posterior segments, were enrolled in this study. The residual alveolar ridge was measured. TSFE without bone grafting was performed. Three months after the first surgery procedure, 66 implants were placed without grafting material. A presurgical distance from the alveolar crest to the floor of the maxillary sinus and the amount of new radiopacity between the sinus floor and alveolar crest were measured from the mesial and distal surfaces of each dental implant surface.

RESULTS

After a mean follow-up period of 10.43 ± 5.01 years (ranged from 5 to 16 years), a survival rate of 95.45% was reported. Mean bone levels at implant placement were 7.12 ± 0.90 mm and, after 1 year, were 13.28 ± 1.23 mm. They were stable over time, reporting an up to 16 years' value of 13.07 ± 2.63 mm.

CONCLUSIONS

The results of this retrospective clinical study confirmed the reliability of the TSFE procedure and the maintenance of bone levels without grafting procedures over time.

A collagenated porcine bone substitute for augmentation at Neoss implant sites: a prospective 1-year multicenter case series study with histology

BACKGROUND

The presence of localized defects and/or small amounts of bone below the maxillary sinus is a common finding, which may compromise implant placement. There is therefore a need for predictable techniques for bone augmentation in such situations.

PURPOSE

The study aims to clinically and histologically evaluate a porcine bone (PB) substitute used for augmentation of the alveolar crest or the maxillary sinus floor prior to or in conjunction with implant placement.

MATERIALS AND METHODS

Nineteen patients were treated with a porcine bone substitute and barrier membranes (OsteoBiol, Tecnoss Dental, Turin, Italy) for lateral bone augmentation (Group 1a) and healing of bone defects (Group 1b) or for augmentation of the maxillary sinus floor using either a replaceable (Group 2a) or an infractured bone window (Group 2b). A total of 34 implants (Neoss Ltd., Harrogate, UK) were placed in conjunction or 5 to 7 months after the procedure. Implants were followed with implant stability measurements at placement and abutment connection, and with intraoral radiographs at abutment connection and after at least 1 year of loading. A biopsy for histology and morphometry was taken at the first reentry operation.

RESULTS

All but one of the procedures was successful (94.7%) as one maxillary sinus procedure (Group 2a) resulted in insufficient bone for implant placement. One of the 34 implants failed, giving an implant survival rate of 97.1% after 1 year. Implant stability measurements showed a mean stability of 71.9 ± 7.7 implant stability quotient (ISQ) at placement, which significantly increased to 75.3 ± 6.8 ISQ at abutment connection (p = .03). The average bone loss was 0.5 ± 0.7 mm during 1 year. Histology revealed new bone formation at the PB surface, which formed bridges between particles and between particles and preexisting bone. The presence of scalloped resorption lacunae and new osteons inside the particles indicated ongoing resorption/remodeling of the particles. The histomorphometric analyses showed that the total specimen area consisted of, in average, 56.5 ± 15.7% mineralized tissue of which 24.8 ± 13.9% of the total area was PB particles.

CONCLUSION

This study showed good clinical results when using a PB substitute and barrier membranes for augmentation of the alveolar crest and maxillary sinus. Histology revealed bone condensation properties and indicated that the material can be resorbed with time.

Antral computerized tomography pre-operative evaluation: relationship between mucosal thickening and maxillary sinus function

OBJECTIVES

to assess the correlation between maxillary sinus inferior mucosal thickening and sinus outflow obstruction.

MATERIAL AND METHODS

the study included 280 computerized tomography (CT) scans (560 maxillary sinuses). CT aimed to assess sinusitis; trauma to the face and intubated patients were excluded. Mucosal thickening was graded as < 5 mm (1), < 10 mm (2), < 15 mm (3), < 20 mm (4) and > 20 mm (5), and classified by appearance as normal, rounded, circumferential, irregular, or complete. Maxillary sinus outflow was classified as patent or obstructed.

RESULTS

mucosal thickening was found in 36.1% of the maxillary sinuses, graded as 31.2% (1), 34.2% (2), 12.9% (3), 5.4% (4) and 16.3% (5), and classified as rounded (11.8%), irregular (10.4%), circumferential (8.8%) and complete (5.2%). Sinus outflow was obstructed in 15% of the scans. Mucosal thickening of < 5 mm (11.1%), < 10 mm (36.2%) and > 10 mm (74.3%) was associated with sinus obstruction (P<0.0001). Rounded (6.1%), circumferential (55.2%), irregular (38.8%) and complete (100%) mucosal appearances were associated with sinus obstruction (P<0.001). When statistically combined, a substantial risk for sinus obstruction was observed with irregular mucosal appearance of > 5 mm (56.5% for grade 2 up to 82.6% for grades 3-5) and circumferential appearance (21.4% for grade 1 up to 100% for grades 3-5). A low risk for obstruction was found with the rounded appearance (mean 6.1%).

CONCLUSIONS

irregular (> 5 mm), circumferential and complete mucosal appearance are associated with an increased risk for sinus outflow obstruction and an ENT consultation is recommended. A rounded mucosal appearance of any grade is associated with a low risk for sinus obstruction. Routine CT scans, including the maxillary sinus ostium, are recommended.

Use of intraoral welding to stabilize dental implants in augmented sites for immediate provisionalization: a case report

Immediate implant rehabilitation of edentulous arches may be somewhat problematic because of anatomic situations involving insufficient bone thickness or height and tooth position. The aim of this report was to present a retrospective case series of dental implants placed into augmented sites (split crest or sinus augmentation) that were stabilized with an intraorally welded framework at the time of immediate provisionalization. An intraoral welding unit was used to join and stabilize implants as an orthopedic splint to break down forces applied on provisional restorations during healing and osseointegration. This approach allows for the immediate provisionalization of implants in bone-defective areas where multiple implant systems have been enacted. Forty-eight implants in 16 patients were inserted, welded together to a titanium framework, and immediately provisionalized during the same surgery in which split-crest or sinus augmentation procedures were performed. After removing the welded frameworks, 1 of 48 implants failed; the failed implant was associated with a sinus augmentation procedure. Intraoral welding stabilization may be a predictable procedure to allow immediate loading in augmented areas during healing time and to stabilize implants against nonaxial forces, thereby reducing the number of surgical and prosthetic sessions and making patients comfortable and accustomed to immediate fixed provisional and definitive restorations.

Are panoramic images reliable in planning sinus augmentation procedures?

OBJECTIVE

The inherent deformation and two-dimensional nature of panoramic radiographs jeopardise their interpretation and quantitative measurements. This study aims to estimate the degree of underestimation of available mesio-distal bone in the premolar area (comparing panoramic radiographs with multi-slice/cone-beam computer tomography [CT]) to determine the prevalence, width, length and position of the bony canal [artery] in the lateral sinus wall and to explore the prevalence, width and length of another (newly detected) bony canal at the palatal aspect of the upper canine.

MATERIAL AND METHODS

The distance between the distal side of the canine/first premolar and the mesial side of the first molar or the anterior wall of the maxillary sinus was measured on panoramic radiographs and corresponding multi-slice/cone-beam CT images (65 patients). Measurements were made at apical, mid-radicular and crestal regions, parallel to the occlusal plane. The presence and dimensions of the two above-mentioned intra-osseous canals were verified on multi-slice CT scans (144 patients) using reformatted cross-sectional images and/or axial slices.

RESULTS

For all 65 patients, panoramic radiographs underscored the mesio-distal distance of available bone in the upper premolar region (mean 2.9 mm, range 0.1-7.5 mm). An intra-osseous canal in the lateral maxillary sinus wall was clearly visible in 49.5% of the cases (mean diameter 1.4 mm). In the canine region, a bony canal was obvious in 32.9% of the cases, with a mean diameter of 1.23 mm. For both canals, there was no correlation between diameter and patient's age.

CONCLUSIONS

Based on the present data, cone-beam CT imaging can be recommended for visualising anatomical structures during planning of sinus augmentation procedures.

Survival rate for implants placed in the posterior maxilla with and without sinus augmentation: a comparative cohort study

BACKGROUND

The reduced bone height and proximity of the maxillary sinus are the most common limitations for placement of dental implants in the posterior maxilla. Reconstruction of the atrophic posterior maxilla can be performed with a sinus augmentation procedure. The aim of this cohort study is to compare the survival rate of implants placed in augmented sinus to implants placed in native bone in the posterior maxilla.

METHODS

This study was designed as a prospective cohort study and included consecutively treated patients. Patients who required the sinus augmentation (test group) were treated according to the two-stage technique. Patients were scheduled for follow-up evaluation at 3, 6, and 12 months after implant placement and then every 6 months for ≤ 6 years.

RESULTS

One hundred and five patients with 393 implants were enrolled in the study. Two hundred and one implants were placed after preliminary sinus floor grafting in 41 patients. The control group contained 64 patients with 192 implants that were placed in pristine bone of the posterior maxilla. The cumulative implant survival rates were 86.1% and 96.4%, respectively. The difference between the two groups was highly significant (P <0.005).

CONCLUSIONS

These findings show that implants placed in augmented sinuses had a lower survival rate compared to implants placed in pristine bone. All the implant failures in the augmented sinuses occurred before the prosthetic rehabilitation. Moreover, it should be considered that most of the failures were observed in few patients, thus suggesting cluster behavior.

Short implants in maxillae and mandibles: a retrospective study with 1 to 8 years of follow-up

BACKGROUND

The aims of this study are to evaluate the long-term survival rates of short dental implants in posterior areas in both jaws and analyze the influence of different factors on implant survival.

METHODS

A retrospective cohort study design was used. Six hundred and sixty-one patients received 1,287 short implants (<8.5 mm) between 2001 to 2008 in Vitoria, Spain. All implant installations were performed by two experienced surgeons and rehabilitations were done by three prosthodontists. Each implant failure was carefully analyzed. The potential influence of demographic factors, clinical factors, surgery-depending factors, and prosthetic variables on implant survival was studied. Implant survival was analyzed using a life table analysis (Wilcoxon [Gehan] test).

RESULTS

The overall survival rates of short implants were 99.3% and 98.8% for the implant and subject-based analysis, respectively. The mean follow-up period for the implants was 47.9 +/- 24.46 months. A total of 9 out of 1,287 implants were lost during the observation period. None of the variables studied resulted in statistical association with implant failure because of the low number of failures.

CONCLUSION

Results of the present retrospective study show that treatment with short implants can be considered safe and predictable if used under strict clinical protocols.

Maxillary sinus augmentation by the crestal core elevation technique

BACKGROUND

The crestal core elevation (CCE) technique is reportedly a less invasive procedure than the lateral window elevation technique. We retrospectively evaluated long-term outcomes of CCE procedures over an 11-year time period.

METHODS

Core preparations were made after extractions of 57 upper molars in 45 patients. Extraction sites were drilled with a calibrated trephine bur to an estimated distance of 1 mm from the sinus membrane. The trephined interradicular bone and underlying sinus membrane were imploded into the sinus. The surgical crater and residual extraction socket were filled with deproteinized bovine bone mineral or freeze-dried bone allograft, stabilized, and protected with an absorbable collagen membrane and fully covered with coronally positioned flaps. Implants were placed 4 months later. Success was defined if ≥9 mm available bone height was available. Where the available bone height varied between 7 and 9 mm, implant placement was complemented using the bone-added osteotome sinus floor elevation technique; those sites were defined as a "partial success."

RESULTS

The CCE technique was successful in 31 (68.9%) out of 45 sites, and partially successful in six (13.3%) out of 45 sites. Eight sites failed (17.8%). Surgical failures were caused by core detachment resulting in large tears of the sinus membrane. Implants placed in successful sites presented a 100% survival rate during the study duration.

CONCLUSIONS

CCE implemented simultaneously with molar extractions provided therapeutic benefits and clinical limitations. The subsequent implant placement using CCE revealed an excellent survival rate in the study population evaluated.

The use of titanium mesh in sinus augmentation

Sinus floor elevation is a clinical procedure to allow implantation in the posterior maxillary areas, in cases of reduced alveolar height. Numerous techniques and materials have been described during the last 2 decades. The aim of this article is to present an innovative technique for sinus lifting procedure. The use of a titanium mesh allows better stability of grafted materials and a more predictable result.

Bone regeneration using a hollow hydroxyapatite space-maintaining device for maxillary sinus floor augmentation--a clinical pilot study

BACKGROUND

The mere lifting of the maxillary sinus membrane by implants protruding into the sinus cavity allows the establishment of a void space for blood clot and new bone formation.

PURPOSE

To evaluate bone formation by using a spherical, hollow, and perforated hydroxyapatite space-maintaining device (HSMD) in a two-stage sinus lift procedure where residual alveolar bone height was ≤2 mm.

MATERIAL AND METHODS

Spherical, hollow, and perforated HSMDs with a diameter of 12 mm were manufactured for this pilot study. Three patients with a residual bone height of 1-2 mm, as verified clinically and radiographically, and in need of a sinus augmentation procedure prior to implant installation were selected for the study. The HSMD and bone formation was evaluated by cone beam computerized tomography (CBCT) 6 months after augmentation procedure. Implants were installed 6 to 9 months after augmentation. The implant sites were prepared by a trephine drill to obtain a specimen of HSMD and bone for histological evaluation. After implant installation, the condition of the sinus membrane adjacent to the HSMD was evaluated endoscopically. After an additional 8 weeks, fixed partial prostheses were fabricated.

RESULTS

Bone formation verified by CBCT was found around and inside the device in all three patients after 6 months. Despite the fact that residual bone before augmentation was ≤2 mm, 12-mm-long implants with diameter of 4.8 mm could be inserted with preservation of an intact and healthy sinus membrane verified endoscopically. Bone formation inside HSMDs was noted histologically in two out of three HSMDs. Implants were stable and without any marginal bone loss after 1 year of prosthetic loading.

CONCLUSION

A spherical, hollow, and perforated HSMD used in sinus lift procedures can produce a void space for blood clot and new bone formation and subsequent implant installation.

An economic evaluation of different sinus lift techniques

PURPOSE

To identify the most cost-effective approach to sinus lifting on the basis of currently available evidence.

METHODS

We incorporate the costs and clinical outcomes of nine different sinus lift techniques within a decision tree model in which costs are based on insurance regulations in Germany and health outcomes follow two recent meta-analyses. The most cost-effective treatment option is identified on the basis of the maximum net benefit criterion. Uncertainties regarding health outcomes are incorporated via probabilistic sensitivity analysis based on Monte-Carlo simulation.

RESULTS

When there are no financial restrictions, the optimum treatment strategy is the lateral approach with autogenous particulate bone and a resorbable membrane. When, however, monetary resources for sinus-floor elevation are scarce, the most cost-effective option is the transalveolar technique without bone grafting. Only if relatively high costs can be afforded or if initial bone height at implant site is below 5 mm is the maximum net benefit achieved by lateral approaches.

CONCLUSIONS

On the basis of currently available evidence, the transalveolar technique is advisable when monetary resources for sinus-floor elevation are scarce and initial bone height is sufficiently high. Lateral approaches are primarily recommended for lower pre-operative bone heights.

Factors associated with failure of surface-modified implants up to four years of function

OBJECTIVES

The relative impact of innovative treatment concepts on the failure of surface-modified implants is not well understood. This retrospective study aimed to explore this using data obtained in a university postgraduate training center.

MATERIAL AND METHODS

Patients treated with implants for a variety of indications over a 3-year period were included. All implants had been at least 1 year in function. Clinical records were evaluated for implant failure and in reference to implant length/diameter/location, time from tooth loss to implant placement, bone condition (native/grafted), surgical protocol (two-/one-stage), loading protocol (delayed/early/immediate), type of prosthesis (removable/fixed), surgeon's experience level (resident/trainee) and specialty (periodontist/oral surgeon). The impact of each covariate on failure was tested using the Fisher's exact test. Kaplan-Meier survival functions were constructed and Mantel-Cox log-rank tests were used to compare survival functions. To correct for possible interaction, Cox proportional Hazards regression was adopted.

RESULTS

Forty-one of 1,180 (3.5%) implants were lost in 34/461 (7.4%) patients (245 ♀, 216 ♂; mean age 51, range 18-90). Factors showing significant impact on failure on the basis of univariate analyses were implant location (p = .015), surgical protocol (p = .002), loading protocol (p = .002), surgeon's experience level (p = .035) and specialty (p = .001). When controlling for other covariates, only the loading protocol had a significant influence (p = .049) with early loading more prone to failure (p = .014) when compared with delayed loading. Immediate loading and delayed loading showed comparable implant survival (p = .311).

CONCLUSIONS

Implant therapy may be highly successful in a training center where inexperienced clinicians are strictly monitored and personally guided. Implant specific variables do not affect implant survival but early loading is a risk indicator for implant failure, whereas immediate loading is not.

A 10-year retrospective analysis of radiographic bone-level changes of implants supporting single-unit crowns in periodontally compromised vs. periodontally healthy patients

AIM

To compare the 10-year peri-implant bone loss (BL) rate in periodontally compromised (PCP) and periodontally healthy patients (PHP) around two different implant systems supporting single-unit crowns.

MATERIALS AND METHODS

In this retrospective, controlled study, the mean BL (mBL) rate around dental implants placed in four groups of 20 non-smokers was evaluated after a follow-up of 10 years. Two groups of patients treated for periodontitis (PCP) and two groups of PHP were created. For each category (PCP and PHP), two different types of implant had been selected. The mBL was calculated by subtracting the radiographic bone levels at the time of crown cementation from the bone levels at the 10-year follow-up.

RESULTS

The mean age, mean full-mouth plaque and full-mouth bleeding scores and implant location were similar between the four groups. Implant survival rates ranged between 85% and 95%, without statistically significant differences (P>0.05) between groups. For both implant systems, PCP showed statistically significantly higher mBL rates and number of sites with BL> or =3 mm compared with PHP (P<0.0001).

CONCLUSIONS

After 10 years, implants in PCP yielded lower survival rates and higher mean marginal BL rates compared with those of implants placed in PHP. These results were independent of the implant system used or the healing modality applied.

A hybrid technique for sinus floor elevation in the severely resorbed posterior maxilla

Purpose

This study aimed to evaluate the effectiveness of the modified sinus floor elevation technique described hereafter as a "hybrid technique," in 11 patients with severely resorbed posterior maxillae.

Methods

Eleven patients who received 22 implants in the maxillary premolar and molar areas by the hybrid technique were enrolled in this study. A slot-shaped osteotomy for access was prepared on the lateral wall along the lower border of the sinus floor. The Schneiderian membrane was fully reflected through the lateral slot. Following drilling with the membrane protected by a periosteal elevator, the bone was grafted. All implants were placed simultaneously with sinus augmentation. The cumulative success rate was calculated and clinical parameters were recorded. Radiographic measurements were performed.

Results

All implants were well maintained at last follow up (cumulative success rate=100%). The mean residual bone height, augmented bone height, crown-to-implant ratio, and marginal bone loss were 4.1±1.64 mm, 8.76±1.77 mm, 1.21±0.33 mm, and 0.34±0.72 mm, respectively.

Conclusions

Simultaneous implant placement with sinus augmentation by hybrid technique showed successful clinical results over a 2-year observation period and may be a reliable modality for reconstruction of a severely resorbed posterior maxilla.