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

Evaluation of bone substitute materials: comparison of flat-panel based volume CT to conventional multidetector CT

Over the last decade tissue engineering has emerged as a key factor in bone regeneration within the field of cranio-maxillofacial surgery. Despite this in vivo analysis of tissue-engineered-constructs to monitor bone rehabilitation are difficult to conduct. Novel high-resolving flat-panel based volume CTs (fp-VCT) are increasingly used for imaging bone structures. This study compares the potential value of novel fp-VCT with conventional multidetector CT (MDCT) based on a sheep sinus floor elevation model. Calcium-hydroxyapatite reinforced collagen scaffolds were populated with autologous osteoblasts and implanted into sheep maxillary sinus. After 8, 16 and 24 weeks MDCT and fp-VCT scans were performed to investigate the volume of the augmented area; densities of cancellous and compact bone were assessed as comparative values. fp-VCT imaging resulted in higher spatial resolution, which was advantageous when separating closely related anatomical structures (i.e. trabecular and compact bone, biomaterials). Fp-VCT facilitated imaging of alterations occurring in test specimens over time. fp-VCTs therefore displayed high volume coverage, dynamic imaging potential and superior performance when investigating superfine bone structures and bone remodelling of biomaterials. Thus, fp-VCTs may be a suitable instrument for intraoperative imaging and future in vivo tissue-engineering studies.

Use of plasma rich in growth factor for schneiderian membrane management during maxillary sinus augmentation procedure

The aim of this pilot study was to present a novel technique for the management of the Schneiderian membrane during maxillary sinus lift surgery using plasma rich in growth factors (PRGF). Eight maxillary sinuses were augmented in 8 patients. Two small perforations of the Schneiderian membrane occurred during the lifting procedure, which were solved using the PRGF clot before grafting the site with PRGF and anorganic bovine bone. With the exception of 1 patient who experienced pain following an acute sinus infection after 3 days of uneventful healing, the patients' postoperative quality of life was generally good. The most common complication (50% of cases) was hematoma, which disappeared after 1 week. Despite the limitations of this study concerning the sample size and the study design, the use of PRGF may be helpful in reducing complications following sinus lift surgery. More well-designed studies, with larger sample size, are needed to validate this protocol.

Palatonasal recess on medial wall of the maxillary sinus and clinical implications for sinus augmentation via lateral window approach

BACKGROUND

Anatomic variations of the maxillary sinus determine the degree of difficulty in performing sinus augmentation. Whereas some variations, e.g., the septum and morphology of the sinus, have been extensively studied, the structure of the medial wall has never been investigated. The aims of this study are to measure the location and angulation of the palatonasal recess (PNR) on the medial wall and identify risk sites that are related to the shape of the PNR.

METHODS

Cone-beam computed tomography (CBCT) scans were screened from the University of Michigan School of Dentistry database. Edentulous sites with <10 mm between the floor of the maxillary sinus and the alveolar crest were selected. The residual ridge height (RH), the distance between the PNR and the alveolar crest, and the angulation of the PNR were measured on the selected sagittal planes. The percentage of sites (risk sites) with recesses that were <90° and <15 mm from the alveolar crest was calculated. The PNR location and angulation were compared among premolar and molar edentulous sites.

RESULTS

Two hundred seventy-four sites were studied. The mean ± SE PNR location was 14.2 ± 2.8 mm, 13.1 ± 2.2 mm, and 12.5 ± 2.5 mm for the second premolar, first molar, and second molar sites, respectively, with significant differences between the second premolar and second molar sites. The mean PNR angulation was 109.8° ± 25.3°, 121.6° ± 22.1°, and 144.9° ± 23.1° in the corresponding sites, with significant differences among the site groups. The respective percentages of risk sites were 15%, 8.2%, and 2.4% in the second premolar, first molar, and second molar sites.

CONCLUSIONS

Maxillary sinuses with acute-angled PNRs might present a challenge for performing sinus augmentation. Therefore, this anatomic structure should be carefully evaluated.

The long-term use of zygomatic implants: a 10-year clinical and radiographic report

BACKGROUND

The zygoma implant has been an effective option in the short-term management of the atrophic edentulous maxilla.

PURPOSE

To report on long-term outcomes in the rehabilitation of the atrophic maxilla using zygomatic (ZI) and regular implants (RI).

MATERIAL AND METHODS

22 consecutive zygomatic patients in a maintenance program were included. Cumulative survival rate (CSR) of ZI, RI, prostheses, and complications were recorded during, at least, 10 years of loading. Implant mobility was tested using Periotest(®). Sinus health was radiographically and clinically assessed according to Lund-Mackay (L-M) score and Lanza and Kennedy survey, respectively. A satisfaction questionnaire and anatomical measurements were also performed.

RESULTS

Patients received 22 prostheses, anchored on 172 implants. Forty-one were ZI. Three RI failed (10 years CSR = 97.71%). Two ZI were partly removed due to perimplant infection (10 years CSR = 95.12%). All patients maintained functional prostheses. One patient fractured framework twice. Loosening or fracturing screws happened in 11 patients. Seven patients fractured occlusal material. Four ZI abutments in two patients were disconnected because of uncomfortable prostheses. Alveolar height at the ZI head level on the right and left sides was 2.64 mm and 2.25 mm, respectively. Mean distance of ZI head center to ridge center, on the right and left sides was 4.54 mm and 5.67 mm, respectively. Mean Periotest values (PTv) of ZI were -4.375 PTv and -4.941 PTv before prostheses placement and after 10 years, respectively. Six patients experienced sinusitis 14-127 months postoperatively. 54.55% of the L-M scores did not present opacification (L-M = 0) in any sinus. Osteomeatal obstruction happened in eight patients (two bilateral). Two (9.09%) were diagnosed with sinusitis. Eighty-four percent reported satisfaction levels above 80%. 31.81% reported maximum satisfaction score (100%).

CONCLUSIONS

The long-term rehabilitation of the severely atrophic maxillae using ZI is a predictable procedure.

Evaluation of maxillary sinus width on cone-beam computed tomography for sinus augmentation and new sinus classification based on sinus width

PURPOSE

The degree of difficulty in performing lateral window sinus augmentation may depend on the morphology of the maxillary sinus. The aim of this was to measure the distances between the medial and lateral sinus wall (sinus width [SW]) at different levels and apply those SW values to formulate a new sinus classification.

MATERIALS AND METHODS

Edentulous sites adjacent to maxillary sinuses with inadequate ridge height (RH; <10 mm) were included from cone-beam computed tomography database in the University of Michigan. SW was measured at the heights of 5, 7, 10, 13, and 15 mm from alveolar crest at the edentulous sites. Mean SW was stratified by residual RH into three different groups (group 1: <4 mm, group 2: ≥4 and <7, and group 3: ≥7 and <10), study sites (first and second premolars and molars), and measurement levels.

RESULTS

Three hundred and twenty subjects (mean 50.1 years old) with 422 edentulous sites were included. Mean SW was wider at molar sites, higher measurement levels, and sites with shorter residual RH. Mean SW at the lower (average 2.3 mm from sinus floor) and higher boundary (15 mm from the alveolar crest) of lateral window osteotomy was 9.0 (2.8) and 16.0 (4.4) mm, respectively. Narrow, average, or wide sinuses were classified when the SW was <8, 8-10 and >10 mm at the lower boundary or <14, 14-17 and >17 mm at the upper boundary, respectively.

CONCLUSION

SW at levels that were relevant to lateral window sinus augmentation was measured. The proposed sinus classification could facilitate communication between health providers and determine the degree of easiness of sinus augmentation. It might be particularly useful for the selection of grafting materials and surgical approaches. Further studies are required to test its clinical implications.

Volume changes of iliac crest autogenous bone grafts after vertical and horizontal alveolar ridge augmentation of atrophic maxillas and mandibles: a 6-year computerized tomographic follow-up

PURPOSE

To evaluate by computerized tomography the long-term volume resorption of autogenous corticocancellous grafted bone harvested from the ilium and used in an alveolar augmentation procedure followed by endosseous dental implant placement.

PATIENTS AND METHODS

Eleven maxillary grafts (8 positioned horizontally) and 13 mandibular grafts (10 positioned vertically) were placed in 16 patients. Using software programs, pre- and postsurgical computerized tomographic scans were used to compare volumes of grafts over time (up to 6 yr) to determine the annual percentage of remaining bone and the overall percentage of bone resorption that could be expected. Yearly measurements of volumes and percentages of remaining bone were then compared statistically.

RESULTS

At the 6-year survey for blocks grafted in the mandible, an average resorption rate of 87% was obtained; for maxillary grafts at the same survey, complete resorption of the grafts (mean, 105.5%) was recorded. In general, bone resorption appeared slow, except for that recorded in the first 2 years of healing, the only period in which statistical comparisons among all time points showed significant differences for all variables.

CONCLUSIONS

Volumetric measurements of the grafts and their related percentages of remaining bone attested to a progressive and unavoidable bone resorption of almost all the grafted bone in the maxilla and mandible. Although the present data were from a heterogeneous group of defects treated with horizontal and vertical procedures, clinicians, when performing alveolar bone augmentation with an autogenous hip bone, should aim at titanium dental implant osseointegration, not only in the augmented bone but also in the native bone below the graft.

Reversible, non-plaque-induced loss of osseointegration of successfully loaded dental implants

OBJECTIVES

Excess loading has been often cited as a reason for the failure of dental implants or bone loss post-osseointegration. The available data from animal studies have failed to show a clear role for excessive loading in the loss of osseointegration. The present case documentations aimed at providing a deeper insight into the medium- to long-term influence of occlusal loading on osseointegrated implants, and describe the clinical manifestations of such pathology.

MATERIAL AND METHODS

Two cases of loss of osseointegration are documented with single implants in the posterior maxilla. Implant mobility was in both cases the first and only sign of pathology, with the absence of plaque-induced inflammation and marginal bone loss.

RESULTS

Re-osseointegration of the implants was achieved after the removal of the prosthetic reconstruction.

CONCLUSIONS

The two cases reported that the loss of osseointegration in the absence of plaque-induced peri-implant inflammation is possible, although the clinical manifestations were very different to these of peri-implantitis. Once the occlusal loading was withdrawn, re-osseointegration was clinically confirmed in a period of 6-8 months.

Osteotome sinus floor elevation with and without grafting material in the severely atrophic maxilla. A 1-year prospective randomized controlled study

OBJECTIVES

(1) To measure and compare endo-sinus bone levels around implants randomly placed with an osteotome sinus floor elevation (OSFE) procedure in grafted (control) and non-grafted (test) sinuses, (2) to evaluate the OSFE efficacy with short, tapered, and chemically modified hydrophilic surfaced implants in extremely atrophic maxillae, (3) to show that fused corticals may constitute a complication risk.

MATERIAL AND METHODS

The TE(®) SLActive 8 mm-long implants (Straumann AG) were placed using an OSFE procedure in 4 mm or less of bone height. Healing time before prosthetic rehabilitation was 10 weeks. One year after implant placement, bone levels were measured on standardized periapical radiographs.

RESULTS

Thirty-seven (17 tests, 20 controls) implants were placed in 12 patients with a mean maxillary residual bone height (RBH) of 2.4 ± 0.9 mm. Before loading, two control implants failed (RBH 1.4 and 1.2 mm); two others rotated at loading (one test, RBH 0.9 mm; one control, RBH 1.5 mm) but were uneventfully loaded after three additional months of healing. These adverse events and complications occurred when implants were placed in merged corticals. Endo-sinus bone gain was 3.9 ± 1.0 and 5.0 ± 1.3 mm for the test and control groups (P = 0.003). The 1-year success rate was 100% and 90%, respectively (P = 0.49).

CONCLUSION

Although more bone is gained when grafting material is used, this may not be required to promote endo-sinus bone gain. The OSFE procedure with or without grafting material could be efficient when the RBH is ≤ 4 mm. However, when both corticals merged, the risk of complication could increase.

The Incidence of Maxillary Sinus Membrane Perforation During Endoscopically Assessed Crestal Sinus Floor Elevation: A Pilot Study

Transcrestal sinus membrane elevation is a surgical procedure performed to increase the bone volume in the maxillary sinus cavity. Because of visual limitations, the potential for maxillary sinus membrane perforations may be greater than with the lateral approach technique. The aim of this study was to macroscopically investigate ex vivo the occurrence of sinus membrane perforation during surgery using 3 transcrestal sinus floor elevation methods. Twenty fresh human cadaver heads, with 40 intact sinuses, were used for simultaneous sinus membrane elevation, placement of graft material, and dental implants. Real-time sinus endoscopy, periapical digital radiographs, and cone-beam computerized tomography (CBCT) images were subsequently used to evaluate the outcome of each surgical procedure. Perforation rates for each of the 3 techniques were then compared using a significance level of P &lt; .05. No statistically significant differences in the perforation rate (P = .79) were found among the 3 surgical techniques. Although the sinus endoscope noted a higher frequency of perforations at the time of implant placement as compared with instrumentation or graft insertion, the difference was not statistically significant (P = .04). The CBCT readings were judged to be more accurate for identifying evidence of sinus perforations than the periapical radiographs when compared with the direct visualization with the endoscope. This pilot study demonstrated that a sinus membrane perforation can occur at any time during the sinus lift procedure, independent of the surgical method used.

Radiographic and histologic evaluation of platelet-rich plasma and bovine-derived xenograft combination in bilateral sinus augmentation procedure

There is currently a great interest regarding the use of platelet-rich plasma (PRP) in combination with various bone graft materials in sinus lift procedures. The purpose of this study was to assess and compare the radiographic and histological results of sinus augmentation procedures following treatment with PRP/bovine-derived xenograft (BDX) vs. BDX/collagen membrane. Using a split mouth design, 10 patients, with ≤5 mm of residual alveolar bone in the vertical direction, were treated with PRP/BDX or BDX/collagen membrane. At 8 months after surgery, both graft materials led to a satisfactory increase in vertical dimensions of bone. Bone biopsies were taken from the augmented sites during the implant placement. Histological analysis demonstrated that majority of the trabecula contained orderly layered lamellar bone in the PRP/BDX group, whereas mainly woven bone with a haphazard arrangement of collagen fibers were noticed in the BDX /collagen membrane group. It can be concluded that both combinations resulted with a satisfactory bone height, but more prominent and mature bone formation was observed at sites treated with PRP/BDX.

Sinus augmentation via transcrestal approach: a comparison between the balloon and osteotome technique in a cadaver study

BACKGROUND

The transcrestal approach with osteotomes is a commonly applied and predictable technique for maxillary sinus floor elevation. However, Schneiderian membrane perforation is a common and often inevitable intraoperative complication. Recently, the use of balloons has been proposed to reduce the risk of sinus membrane perforation and to facilitate the surgical technique. The aim of this study was to determine membrane elevation height and perforation rate using the transcrestal balloon technique (B) and a conventional osteotome approach, as control (C).

METHODS

Ten fresh, completely edentulous cadaver heads (seven male and three female) were selected. In a split-mouth design, each sinus was randomly assigned to either the experimental or the control technique. Pre-surgical planning was aided by cone-beam computed tomography. During the procedure, an endoscope was used to monitor the elevation procedure and the occurrence of sinus perforation. The elevation continued until either 15 mm (measured from the alveolar crest) was reached or a perforation occurred. The residual ridge and the elevated membrane height were measured and compared with the paired Student's t-test. Presence of sinus perforation was recorded at three cutoff points: 10, 12, and 15 mm.

RESULTS

The mean age of the specimens was 77.7 ± 14.2 years (range 49-92). The mean initial, final, and elevated sinus membrane height for the B group was 5.3 ± 1.9, 13.7 ± 1.9, and 8.3 ± 3.1 mm, whereas the correspondent values for the C group were 5.1 ± 2.1, 13.2 ± 2.8, and 8.1 ± 3.1 mm. The incidence of sinus perforation, using 10, 12, and 15 mm as end points was 0%, 22.2%, and 44.4% in the B group, whereas in the C group the respective values were 10.0%, 20.0%, and 50.0%. No statistically significant differences were found between the two groups for all the above-mentioned variables. In addition, mean residual ridge height was not significantly different between the non-perforation and perforation sites in the B group (5.2 ± 2.2 and 5.5 ± 1.7 mm) and in the C group (5.2 ± 2.5 and 5.0 ± 2.0 mm). Three cadavers had perforations in both sinuses, accounting for 66.6% of total number of perforations.

CONCLUSIONS

Based on the findings of this study, the balloon and the conventional osteotome approach are comparable in terms of perforation rate as it relates to the elevation height. Also, the amount of residual alveolar bone was not related to the incidence of perforation and the height of sinus elevation.

Maxillary sinus augmentation with iliac autograft - a health-economic analysis

PURPOSE

To estimate and compare the costs of maxillary sinus augmentation performed with autologous bone graft either from the iliac crest or from local bone harvested from the mandibula. To evaluate post-operative health-related quality-of-life parameters for patients subjected to sinus augmentation and iliac bone surgery.

MATERIAL AND METHODS

The hospital records of 14 patients subjected to sinus augmentation with iliac autograft, and 14 patients treated with local autograft, were analysed with regard to costs related to surgery, hospitalization and sick leave. Post-operative health parameters were assessed with a questionnaire.

RESULTS

Mean hospital costs, administration excluded, for sinus augmentation with iliac autograft was €3447. Policlinic treatment alternatives e.g. local bone autograft with or without bone substitutes, rendered costs of approximately 42% thereof. The loss of production for a worker was 41% of the total cost (€9285). With regard to health-related quality-of-life and post-operative morbidity, most of the patients had recovered 14 days after the iliac graft surgery.

CONCLUSION

The cost for a sinus augmentation with iliac surgery exceeds that of a policlinic procedure manifold. Provided that a policlinic operation with local bone, with or without bone substitute, renders an adequate end result, the economic gain would be substantial and post-operative morbidity would be greatly reduced.

Trans-Socket Elevation/Fracture/Perforation of the Sinus Floor Through the "Infected" Maxillary Tooth Socket to Facilitate Bicortical Fixation of Dental Implants

INTRODUCTION

In the region of the posterior maxilla, a reduced bone depth implies a need for bone augmentation. Such augmentation has been performed via the lateral window approach or a transcrestal approach. Historically, the inferior bony crest opposite the maxilla has been edentulous and free of infection. This case series demonstrates that the maxillary extraction socket can be used predictably as the conduit for an intentional sinus penetration/perforation or fracture (sinus elevation) even in the presence of apical infection. This allows the full use of all the available bony depth below the sinus floor and the floor itself, to achieve acceptable primary fixation of an immediately placed dental implant. To the best of my knowledge, this is the first clinical and radiologic report of such a procedure.

CASE SERIES

All 10 cases presented had maxillary teeth whose extraction was planned. All teeth had areas of radiolucency (or infection) in close proximity to the sinus floor. The available depth of bone at all sites exceeded 5 mm. All the vacated sockets were prepared for implant placement, 1 to 2 mm below the sinus floor. Osteotomes were used through the socket to penetrate or fracture the sinus floor. No bone substitutes were used to augment the bone depth. The implants were immediately placed into the prepared sites with high primary stability.

CONCLUSIONS

This case series demonstrates that the presence of radiolucencies or infection does not contraindicate using the socket as a conduit for sinus floor penetration or fracture. The technique will be easily managed by clinicians who practice conventional sinus floor elevation.

Crestal sinus lift with sequential drills and simultaneous implant placement in sites with <5 mm of native bone: a multicenter retrospective study

PURPOSE

The aim of this multicenter retrospective clinical study was to evaluate the survival rate of implants placed in the posterior maxilla with a residual bone height of <5 mm.

MATERIALS AND METHODS

One hundred seventeen patients, recruited from 6 different centers, had 134 implants placed below the maxillary sinus. The patient population consisted of 52 men and 65 women ranging in age from 39 to 78 years (mean age, 53.2 years). Sinus lift procedures were performed following a crestal approach using a specific sequence of drills (Cosci's technique). All implants were submerged. Periapical radiographs were obtained with a paralleling technique and were digitized. The pattern of bone remodeling was subsequently evaluated.

RESULTS

The average (±SD) follow-up time was 48.2 months (±29.30 months; range, 24 to 120 months). Of the original 134 implants placed, 5 implants (3.7%) failed. The implant survival rate was 96.3%. The average residual bone height was 3.46 mm (±0.91 mm) at baseline. The average height of the alveolar crest in the treated implant sites was 9.94 ± 2.29 mm. The radiographic bone gain was 6.48 ± 2.38 mm.

CONCLUSION

The investigation suggests that this crestal drill approach can be a successful sinus lifting procedure in a severe atrophic maxilla with <5 mm of crestal bone height.

The treatment of sinusitis following maxillary sinus grafting with the association of functional endoscopic sinus surgery (FESS) and an intra-oral approach

AIM OF THE STUDY

To present the results of a prospective study on the management of infectious complications following maxillary sinus floor elevation procedures with a combined endoscopic (FESS) and intra-oral approach.

MATERIALS AND METHODS

From 2005 to 2009, twenty consecutive patients were diagnosed for sinusal chronic infectious complications refractory to medical treatment following maxillary sinus floor elevation and grafting procedures. All patients were treated with a combination of functional endoscopic sinus surgery (FESS) through a transnasal approach and an intra-oral approach, performed by an ear, nose, and throat team and an oral and maxillofacial team, respectively, in the same surgical session under general anesthesia.

RESULTS

In 16 of 20 patients, the 4-week endoscopic control demonstrated a complete clinical healing and recovery of the normal sinus ventilation and drainage. In two patients, the persisting sinusitis at the 4-week control was successfully treated (8th week) with an antibiotic therapy based on the antibiogram carried out on the bacterial culture obtained by the aspiration of the sinusal content. In one patient, the persisting sinusitis (3 months after surgery) was successfully treated with the aspiration of the infectious material from the maxillary sinus. In one patient, finally, it was necessary to perform a second combined surgical treatment to treat the persisting sinusitis.

DISCUSSION AND CONCLUSIONS

In this study, a relevant number of cases of chronic infectious complications following sinus floor elevation procedures are presented. To the authors' knowledge, it is the first time that well-defined treatment protocols based on a combined endoscopic (FESS) and intra-oral surgical approach are proposed. The positive, albeit preliminary, results obtained in this study seem to validate this treatment modality.

Maxillary sinus augmentation with a sonic handpiece for the osteotomy of the lateral window: a clinical report

Several techniques have been proposed to manage patients with insufficient bone height for implant placement in the posterior maxilla. The lateral approach to sinus elevation is a successful procedure, with percentages of success close to 100%. Unfortunately, a frequent complication encountered during sinus elevation procedure is perforation of the Schneiderian membrane. In this clinical report, the authors present the application of a diamond coated sonic tip and an air-driven sonic instrument, commonly used in prosthodontics for the preparation of the lateral window osteotomy during sinus augmentation procedures.

Membrane perforation in sinus floor elevation - piezoelectric device versus conventional rotary instruments for osteotomy: an experimental study

PURPOSE

Sinus membrane perforation is the most common intraoperative complication of maxillary sinus floor elevation (MSFE) procedures and frequently causes postoperative problems. Piezoelectric devices have been claimed to reduce the frequency of membrane perforations although no clear evidence supports this view.

MATERIALS AND METHODS

Ten surgeons with different expertise levels performed 80 MSFEs in selected lamb heads, with rotary and piezoelectric instruments following standard protocols. After the procedures, specimens were coded and perforations or tears determined through a microscope.

RESULTS

No significant differences in terms of thickness either of the sinus lateral wall (xi -xj  = 73.2; 95% confidence interval [CI] = 45.3-191.8) or the membrane (xi -xj  = 24.2; 95% CI = -29.4 to 77.9) were identified between the specimens allocated to each group. Nine membrane perforations (11.2%) occurred during the study, all within the lower expertise group. Membrane elevation by hand instruments caused five perforations (40%) in the rotary instrument group and one in the piezoelectric group. Expert surgeons produced no membrane perforations, the size of the antrostomy that was smaller in the piezoelectric group being the only significant difference between the rotary and piezoelectric groups.

CONCLUSIONS

The use of piezoelectric material for MSFE reduces the frequency of membrane perforation among surgeons with a limited experience.

Pre- and postoperative assessment of sinus grafting procedures using cone-beam computed tomography compared with panoramic radiographs

OBJECTIVES

The present study evaluated the clinical validity of cone-beam computed tomography (CBCT) scans in comparison to panoramic radiographs regarding preoperative implant planning in combination with sinus grafting procedures.

MATERIALS AND METHODS

Preoperative assessment of the maxillary sinuses and implant planning using panoramic radiographs and CBCT scans was performed on 16 sinuses (13 patients) and comprised choice of treatment, timing of implant placement, sinus morphology, level of confidence, complication prediction and graft volume assessment. Six examiners were involved in the study.

RESULTS

In the majority of cases there was a concordance between the treatment type based on either panoramic radiographs or CBCT. If any difference was found, this was due to an overestimation of bone quantity and quality on panoramic radiographs. The assessment of sinus morphology showed a significantly higher detection rate of sinus mucosal hypertrophy on CBCT. The most appealing result is a significant increase in surgical confidence and a significantly better prediction of complications when using CBCT.

CONCLUSIONS

A preoperative planning based on CBCT seems to improve sinus diagnostics and surgical confidence.

Importance of ENT assessment in stratifying candidates for sinus floor elevation: a prospective clinical study

OBJECTIVES

The aim of this article was to describe our experience in the field of preoperative ear, nose and throat (ENT) assessment in each candidate for (maxillary) sinus floor elevation (SFE) after the introduction of a systematic protocol. The protocol evaluates the sinus compliance by means of ENT preliminary examination with nasal fiberoptic endoscopy to identify all of the situations that may predispose to post-lifting complications, i.e. potentially irreversible (PIECs) and presumably reversible (PRECs) ENT contraindications to SFE, and to evaluate its impact on SFE success.

MATERIAL AND METHODS

Patient candidates for SFE were carefully assessed by means of case-history collection, complete ENT evaluation with nasal fiberoptic endoscopy and imaging to detect PIECs, PRECs, or no ENT contraindications for SFE. In case of PRECs, SFE was postponed until complete clinical recovery. Impact of preoperative ENT assessment on SFE outcome was assessed by means of post-lifting telephonic interview and ENT evaluation.

RESULTS

PRECs were detected and resolved before SFE was performed in 38.2% of our 34 patients; no intra- or post-lifting complications occurred in the patients with no ENT contraindications or PRECs.

CONCLUSIONS

The results of the study suggest that a careful multi-tasking preoperative management, including an ENT assessment with fiberoptic endoscopy and a radiological evaluation extended to the ostio-meatal complex, is very useful in candidates for SFE.

Maxillary sinus lift with solely autogenous bone compared to a combination of autogenous bone and growth factors or (solely) bone substitutes. A systematic review

Literature regarding the outcome of maxillary sinus floor elevation to create sufficient bone fraction to enable implant placement was systematically reviewed. Bone fraction and implant survival rate were assessed to determine whether grafting material or applied growth factor affected bone fraction. Trials where sinus floor elevations with autogenous bone (controls) were compared with autogenous bone combined with growth factors or bone substitutes, or solely with bone substitutes (test groups) were identified; 12 of 1124 fulfilled all inclusion criteria. Meta-analyses comparing the bone fraction after applying: autogenous bone; autologous bone with growth factors (platelet rich plasma); or autogenous bone and bone substitutes (bovine hydroxyapatite, bioactive glass, corticocancellous pig bone) revealed no significant differences in bone formation after 5 months. A significantly higher bone fraction was found in the autogenous bone group compared to the sole use of β-tricalciumphosphate (P=0.036). The one-year overall implant survival rate showed no significant difference between implants. Bone substitutes combined with autogenous bone provide a reliable alternative for autogenous bone as sole grafting material to reconstruct maxillary sinus bony deficiencies, for supporting dental implants after 5 months. Adding growth factors (platelet rich plasma) to grafting material and the sole use of β-tricalciumphosphate did not promote bone formation.

Effect of maxillary sinus floor augmentation on sinus membrane thickness in computed tomography

BACKGROUND

Little is known about maxillary sinus compliance, i.e., the intrinsic potential of the sinus membrane to resume its homeostatic status after the surgical trauma caused by sinus floor elevation. The aim of the present study is to investigate the effect of maxillary sinus floor augmentation on sinus membrane thickness.

METHODS

Within-patient comparison of computed tomographic scans before bone grafting versus 4 to 6 months after bone grafting was performed. Changes in membrane thickness were evaluated in 65 maxillary sinus floor augmentation procedures via a lateral approach in 35 patients without clinical signs of sinus pathology at any time.

RESULTS

Sinus membrane thickness differed significantly before (0.8 ± 1.2 mm) versus after (1.5 ± 1.3 mm) augmentation surgery (P <0.001), with a mean increase of 0.8 ± 1.6 mm (maximum: 4.4 mm). Only 28% of augmented sinuses did not show membrane thickening. In non-augmented control sinuses, there was no evidence of membrane thickness increase.

CONCLUSIONS

The results indicate that the maxillary sinus membrane, even in healthy clinical conditions, undergoes morphologic modifications after sinus floor elevation, yet membrane reactions demonstrate significant variability. Future research on the effect of augmentation surgery on maxillary sinus physiology is recommended.

Prognosis of implants and fixed restorations after lateral sinus elevation: a literature review

Aim of this review was to investigate the prognosis of implants inserted in augmented sinuses and fixed restorations supported by these implants. Special attention was given to the impact of grafting material, time of implant placement, residual bone height and type of fixed restoration. An electronic search in PubMed, the German database medpilot and the Cochrane Library was executed followed by supplementary manual search in relevant journals. The search was limited to human studies published up to November 2010. Only publications in English and German, in peer-reviewed journals, were considered. After the initial search and application of selection criteria on titles and abstracts, a full-text analysis of 67 articles was performed, out of which six prospective and three retrospective studies were finally included in the review. The heterogeneous properties of the identified articles did not allow systematic analysis of the data. Success rates of implants were between 96·3% and 100%, survival rates were between 75% and 100%, and survival rates of single crowns, splinted crowns and fixed partial dentures ranged between 96·4% and 100% after a follow-up of 12-101 months. Within the limits of this review, the prognosis of implants and fixed restorations seemed not to be influenced by the type of restorations, graft material, residual bone height and time of implant placement. However, conclusions of this review are based on studies with low level of evidence; therefore, careful interpretation is required. Multicentre randomised controlled clinical trials with sufficient statistical power concentrating on few factors are needed to reach sound conclusions.

Complications associated with implant migration into the maxillary sinus cavity

BACKGROUND

Migration of dental implants into the maxillary sinus is an uncommon, but increasingly reported complication. Implant migration may result from initial lack of primary stability, intrasinusal and nasal pressure changes, autoimmune reaction to the implant or incorrect distribution of occlusal forces. This retrospective study aims at analyzing the factors that may influence implant migration into the maxillary sinus cavity.

MATERIAL AND METHODS

Fourteen patients presenting a total 15 implants that migrated into the maxillary sinus were recruited. Diagnosis of this complication was based on imaging techniques, such as cone beam computerized tomography scan and panoramic radiography. Clinical data were recorded in all cases and processed for statistical analysis.

RESULTS

ABH was below 6 mm in the majority of cases. However, almost 50% of the patients did not receive any site preparation treatment prior to implant insertion. Five patients (33.3%) were treated by osteotome techniques, but only one of them had bone grafting. Therefore, 73.3% of sites did not receive any biomaterial to increase available bone height. The most common complication-associated factors found on this study were related to implant design (cylindrical), implant dimension (diameter), implant restoration/rehabilitation method (partial removable denture), site-specific anatomy (initial residual bone height between 5 and 6.9 mm), demographics (age), and biomaterials.

CONCLUSION

Patient selection and proper treatment planning, as well as the application of the appropriate sinus augmentation technique, are critical aspects that should be controlled to minimize the risk of implant migration into the maxillary sinus cavity.

Bone regeneration using porous titanium particles versus bovine hydroxyapatite: a sinus lift study in rabbits

AIM

The first objective of this study was to qualitatively and quantitatively assess the bone formation process, particularly the long-term behavior and three-dimensional volume stability of subsinusal bone regeneration, using titanium (Ti) or bovine hydroxyapatite (BHA) granules, in a rabbit model. The second objective was to evaluate the effect of the hydration of the BHA particles with a therapeutic concentration of doxycycline solution on the osteogenesis and biomaterial resorption.

MATERIALS AND METHODS

Rabbits underwent a double sinus lift procedure using one of three materials: grade 1 porous Ti particles, BHA, or BHA hydrated with doxycycline solution (0.1mg/ml) (BHATTC). Animals were sacrificed after 1 week, 5 weeks, or 6 months. Samples were analyzed using µCT and nondecalcified histology.

RESULTS

The materials used in each of the three groups allowed an optimal bone formation; bone quantities and densities were not statistically different between the three groups. At 6 months, more stable three-dimensional volume stability was found with Ti and BHATTC (p=.0033). At 5 weeks and 6 months, bone to material contact corroborating osteoconduction was significantly higher with BHA and BHATTC than with Ti (p<.0001).

CONCLUSIONS AND CLINICAL IMPLICATIONS

Even though the studied biomaterials displayed different architectures, they are relevant candidates for sinus lift bone augmentation prior to dental implants because they allow adequate three-dimensional stability and osteogenesis. However, to recommend the clinical use of Ti, both an observation on the drilling effects of Ti particles and clinical trials are needed.