A clinical study on the 6-year outcomes of immediately loaded three implants for completely edentulous mandibles: "the all-on-3 concept".

The objective of the current study was to demonstrate the 6-year clinical and radiological treatment outcomes of the technique performed by immediately loading of three implants (single straight in the mid-line and two tilted distal implants) for the management of total edentulous mandibles and introduce a simple decision matrix for selection of the most appropriate protocol in cases with insufficient length of the interforaminal area. Re-assessments were performed over a total observation period of 6 years after surgery via measurement of bone resorption around implants, bleeding on probing, plaque accumulation, periodontal probing depth, bite force measurements and oral health impact profile. A total of 29 patients (45% women and 55% men) with a mean age of 65 ± 6 years enrolled in the study. 14 patients received an acryl-based bridge as definitive prosthetic restoration and 15 patients received a ceramic-based restoration. Both during the immediate loading phase and during the 6-year follow-up, there was no implantation loss. Regardless of the implant position, all implants showed continuous bone loss over the observation time. The bone loss around dental implants during observation period was only maximum 1.0 ± 1 mm and it remained well within the limits for 'success' according to the 2007 Pisa consensus (< 2 mm). The plaque index showed no significant fluctuations between the implant positions and the individual examination times. The approach described herein might help the surgeon by avoiding unnecessary loss of bone strength, selecting implant sites, and establishing the biomechanical advantage of increased A-P spread for immediate function.

A 5-year prospective clinical trial on short implants (6 mm) for single tooth replacement in the posterior maxilla: immediate versus delayed loading.

The aim of this paper was to demonstrate the treatment outcomes following immediate functional loading concept of short implants inserted for single tooth replacement in the posterior maxilla. The study was performed on 63 patients who received short (6 mm) implants for single tooth replacement in the posterior maxilla. Forty-eight patients underwent immediate functional concept, whereas 15 of the implants were loaded 3 months after insertion. The patients were evaluated for up to 5 years after prosthesis completion. The endpoints included the evaluation of implant survival rate, crown length, bone resorption, plaque accumulation (PI), bleeding on probing (BOP), periodontal probing depth (PPD) and assessment of oral health impact profile (OHIP). At the end of the follow-up period of 5 years, three implants (6.3%) from the immediate loading group have failed during the observation period. Bone loss was significantly lower in the delayed loading group compared to the immediately loaded implants. At the end of the second year, BOP values were higher in the immediately loaded group. Throughout the observation period, PI values in the group with immediate loading were higher. PPD increased consistently and during the first 3 years in the immediate loading group. As a conclusion, short implants inserted for single tooth replacement at the posterior maxilla presented with satisfactory clinical outcomes in both immediate and delayed loading concepts. However, immediately loaded implants presented with an increased bone loss and higher BOP values. As assessed by the OHIP score, a subjective improvement was observed in both groups without significant differences.

MatrixMANDIBLE preformed reconstruction plates--a two-year two-institution experience in 71 patients.

PURPOSE: To evaluate handling, complication rates, clinical and treatment outcomes of the MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs), in particular with regard to the frequency of fatigue fractures and operative time. PATIENTS AND METHODS: A cohort of 71 subjects with an indication for a load-bearing osteosynthesis of the mandible was enrolled in the present study. The indications for plate use were defects due to tumor, trauma, or osteonecrosis. The outcome variables were fitting accuracy, application time, and postoperative complications, defined as plate exposure, loosening of plates or screws, plate fracture, and orocutaneous fistulas. Additionally, the feasibility of a transoral approach was tested. RESULTS: The sample included 71 subjects with a mean age of 54.8 ± 15.0 years, including 43 men (60.6%). MMPRPs could be placed in 70 of the 71 patients. In 10 patients a transoral approach for plate application was successfully performed. The mean time investment to contour the plates was 13.1 minutes. The fitting accuracies of the nonbendable sections were satisfying. No plate fracture was observed within an average follow-up period of 11.8 months. Postoperative complications occurred in 19 (27.1%) of the 70 patients. Plate removal was required in 11 (15.7%) of 70 patients. CONCLUSIONS: The results of the present study suggest that the use of MMPRPs coincides with a reduced operative time and a minimized risk of fatigue fractures. Thus, MMPRPs seem to be a useful standard device in a scope of indications for load-bearing osteosynthesis of the anterolateral division of the mandible, additionally facilitating a transoral approach for application.

Retention of different temporary cements tested on zirconia crowns and titanium abutments in vitro.

PURPOSE: The aim of the present study was to examine the retention force of monolithic zirconia copings cemented with various temporary cements on implant abutments in vitro. METHODS: Sixty exercise implants with pre-screwed implant abutments were embedded in resin. Subsequently, 60 CAD/CAM manufactured zirconia copings were divided into three main groups [Harvard Implant Semi-permanent (HAV), implantlink semi Forte (IMP), Temp Bond NE (TBNE)]. The zirconia copings were cemented on the implant abutments and loaded with 35 N. Specimens were stored in distilled water (37 °C) for 24 h. Half of the test specimens of each group were subjected to a thermocycling (TC) process. Retention force was measured in a universal testing machine. Using magnifying glasses, the fracture mode was determined. Statistical analysis was performed applying the Kruskal-Wallis test, the post hoc test according to Dunn-Bonferroni and a chi-square test of independence. RESULTS: Without TC, IMP showed the highest retention of the three temporary luting agents (100.5 ± 39.14 N). The measured retention forces of IMP were higher than those of HAV (45.78 ± 15.66 N) and TBNE (61.16 ± 20.19 N). After TC, retention was reduced. IMP showed the greatest retentive strength (21.69 ± 13.61 N, three fail outs). HAV and TBNE showed pull-off forces of similar magnitude (17.38 ± 12.77 N and 16.97 ± 12.36 N, two fail outs). The fracture mode analysis showed different results regarding the tested cements before and after TC (facture type before/after TC): IMP (III+II/III), HAV (I/II) and TBNE (III/III). There were clear differences of the fracture modes regarding the examination before and after TC. CONCLUSIONS: Within the limits of this study, IMP showed the highest pull-off forces under the chosen test conditions. All three temporary luting agents showed lower retention forces after TC. Retention values in the individual cement classes were very heterogeneous. Easy cement removal in the crown lumen favours the dominance of adhesive cement fractures on the abutment and adhesive/cohesive cement fractures on the abutment with HAV appears advantageous in case of recementation of the superstructure.

The development of plate osteosynthesis for the treatment of fractures of the mandibular body - a literature review.

PURPOSE: Today plate and screw osteosynthesis of mandibular fractures is a standard procedure in routine clinical practice. In this review, the breakthroughs and drawbacks of the development of this important aspect of maxillofacial surgery are followed-up. METHODS: Medline search of relevant English and German literature. RESULTS: In 1886, Carl Hansmann was the first who applied steel screws and plates. Until today the material, the types of plates and applications have been continually improved. Over the last two decades miniplate osteosynthesis has induced a revolution in mandibular fracture treatment. The modern systems provide better handling, higher stability and less pressure on the bone. CONCLUSION: Modern miniplates have great advantages, like the intra-oral approach and the easy adaptability. In addition, it is no longer necessary to expose bone as extensively.

Outcome and complications after treatment of facial fractures at different times in polytrauma patients.

Finding the correct point of time for operative treatment of facial fractures in multiply injured people remains one of the most important challenges in modern emergency medicine. Findings relating to pathophysiological mechanisms after severe trauma argue against the early operative treatment of non-life-threatening injuries. Our retrospective analysis investigated the effects on complications and outcome of different time points for operative treatment of maxillofacial fractures in multiply injured patients. Over a period of 10 years (2003-2012) we could identify 1543 patients, of whom 553 had fractures of the facial skull. 168 of the facial fracture patients were operated on their fractures, 97 at a time later than 72 h. Despite the delayed time of operation, the patients showed fewer complications (21.6% vs 25.4%). This resulted in fewer additional stays in hospital (9.3% vs 11.3%), and also in fewer plate removals (23.7% vs 33.8%). We conclude that delayed operative fracture treatment does not lead to more complications. The optimal time for operative treatment has to be determined individually as the earliest point at which no adverse effects from comorbidities are expected.

Customized mandibular reconstruction plates improve mechanical performance in a mandibular reconstruction model.

The purpose of this paper was to analyze the biomechanical performance of customized mandibular reconstruction plates with optimized strength. The best locations for increasing bar widths were determined with a sensitivity analysis. Standard and customized plates were mounted on mandible models and mechanically tested. Maximum stress in the plate could be reduced from 573 to 393 MPa (-31%) by increasing bar widths. The median fatigue limit was significantly greater (p < 0.001) for customized plates (650 ± 27 N) than for standard plates (475 ± 27 N). Increasing bar widths at case-specific locations was an effective strategy for increasing plate fatigue performance.

Implantation of the Jarvik 2000 left-ventricular-assist-device: role of the maxillofacial surgeon.

The Jarvik 2000 system of axial-flow LVAD-is implanted for permanent mechanical circularly support in patients with end-stage heart failure waiting to undergo heart transplantation. The battery is connected with a power plug to the percutaneous skull-mounted footplate, which is monocortically fixated to the retro auricular bone. Patient selection should be highly specific, including careful preoperative evaluation. No device failures have been published so far, but complications can occur due to heparinisation. We describe the procedure from the perspective of the maxillofacial surgeon and give suggestions to prevent surgical complications.

Principle and stability of locking plates.

A new internal Mini-Locking-System was tested compared with conventional 2.0 mm Miniplates. Standardised osteotomies in the angular region of 16 human cadaver mandibles were fixed with a 6-hole-plate at the oblique line. Osteosynthesis and stability of fixation was proofed in a three-dimensional in-vitro-model in which functional load was simulated. Comparison of the different osteosynthesis techniques showed that in the case of Miniplate fixation torsion and gapping of the bone fragments occurred following plate application and screw tightening when the plates were pressed onto the bone, so last incongruences between bone surface and plate were transferred to the mobile bone fragments resulting in more extended gaps and torsion. This was only observed to a much lesser extent with the Mini-Locking-System due to the fixation principle avoiding pressure to the bone. During functional loading the Mini-Locking-System showed also a significant higher stability in comparison to conventional Miniplates. Due to the fixation method imitating the principles of a fixateur the screws form together with the plate and the cortical bone a frame construction. Loading forces are transmitted without the need of plate friction directly from bone over the screws to the plate resulting in higher stability.

Immediate loading of 2 interforaminal dental implants supporting an overdenture: clinical and radiographic results after 24 months.

PURPOSE: In this study, preliminary results of immediate loading of ITI sandblasted, large-grit, acid-etched (SLA) implants with a bar-connected overdenture in the edentulous mandible are presented. MATERIALS AND METHODS: Ten edentulous patients between 48 and 74 years old were included in this study. All patients received 2 SLA-surfaced ITI solid-screw dental implants in the interforaminal region, which were loaded with a bar connector and an overdenture 1 day after implant placement. Marginal bone resorption was evaluated using periapical radiographs. Gingival health (ie, Bleeding Index) and patient satisfaction (measured using a visual analog scale) were evaluated. Follow-up time was 24 to 36 months (mean time 29.8 months) after implant loading. RESULTS: Twenty-four months after placement, none of the 20 implants had failed. Marginal bone resorption around all implants after 12 months averaged 0.71 mm, and 92% of the sites had a Bleeding Index of 0. Between 12 and 24 months, average bone resorption was an additional 0.08 mm. All patients demonstrated an improved quality of life. DISCUSSION: The amount of bone resorption was comparable to amounts reported in studies with standard loading times. The low rate of inflammation of the peri-implant soft tissue and the high level of patient satisfaction in this study demonstrate encouraging short-term results. CONCLUSION: The results suggest that immediate loading of 2 dental implants can be successful and further support the use of a rough implant surface in residual bone.

Marginal flap versus paramarginal flap in impacted third molar surgery: a prospective study.

OBJECTIVE: A clinical prospective study was carried out to compare 2 flap designs-marginal and paramarginal-that are used during impacted third molar surgery. MATERIALS AND METHODS: Twenty-seven healthy patients (ages 17 to 31 years) who underwent surgical removal of 4 impacted third molars, including 54 lower and 54 upper, were included. A marginal flap was used in 1 randomly chosen half of the jaw, and a paramarginal flap was used in the other half. The influence of these flaps on wound healing, periodontal pocket depth of the adjacent second molar, pain, trismus, and swelling was studied. RESULTS: Wound dehiscences developed in 8 paramarginal flap cases, whereas none occurred with the use of a marginal flap. The buccal and distal probing depths of the adjacent second molar were significantly bigger in marginal flaps at 5 and 10 days after surgery. However, the probing depth was similar with the use of both techniques at 3 months. Pain, trismus, and swelling were similar with both techniques. CONCLUSIONS: We found no advantages to the use of a paramarginal flap instead of a traditional marginal flap for removing impacted third molars.

The effect of gabapentin-lactam hydroxamic acid derivatives on ovine osteoblast proliferation and phenotype: perspectives for tissue engineering application.

PURPOSE: Modern bone tissue engineering associated with mesenchymal stem cells (MSCs) provides promising treatment alternatives for the loss of bone, one of the foremost challenges in oral and craniofacial surgery today. The effect of gabapentin-lactam (GBP-L) and its analogs on osteogenic differentiated MSCs has not yet been deciphered. Consequently, this study investigates the effect of novel trans-8-tertbutylgabapentin-lactam (trans-8-TB-GBP-L) hydroxamic acid derivatives on metabolism, proliferation, and physiologic mineralization characteristics of ovine osteoblast cells. MATERIALS AND METHODS: Osteoblasts were extracted and prepared from sheep femoral heads and cultured in medium enriched with hydroxamic acid derivatives of trans-8-TB-GBP-L. The cell proliferation rate, cell metabolism, cell viability, and basic osteoblastic function were assessed. RESULTS: After 3 and 5 days of incubation, no significant increase in DNA content was detected in any of 12 test groups versus the control group. However, after 8 days of incubation, a significant increase of DNA contents in the test groups containing nanomolar concentrations of trans-8-TB-GBP-L hydroxamic acid derivatives was found. No significant aberration in metabolic activity was detected when any of the test substances were applied. ALP displayed similar activity rates among the test groups and the control at all time points. Calcification of osteoblastic cells occurred solely when nanomolar concentrations were used. CONCLUSION: Trans-8-TB-GBP-L hydroxamic acid derivatives do not interfere with physiologic function and phenotype of ovine osteoblasts. However, when applied at nanomolar concentrations, the assessed GBP-L derivatives significantly increased the cell proliferation rate after 8 days of incubation, indicating a dose-response curve with the maximum peak at nanomolar concentration and a retarded drug response between 5 and 8 days.

Follow-up of implant survival comparing ficoll and bone marrow aspirate concentrate methods for hard tissue regeneration with mesenchymal stem cells in humans.

OBJECTIVE: Clinical follow-up of implant survival in 11 patients comparing two different methods for mesenchymal stem cell (MSC) isolation (Ficoll and bone marrow aspirate concentrate [BMAC]) applied in maxillary sinus augmentation. METHODS: Mononuclear cells, including MSCs, were concentrated with either Ficoll (control group, n=6 sinus) or BMAC (test group, n=12 sinus) and transplanted in combination with bovine bone mineral. A total of 50 implants were placed in a second surgical intervention (17 Ficoll/33 BMAC) and loaded after 4 months. Overall implant survival was assessed with a Kaplan-Meier model using package survival under R. RESULTS: Implant survival of the Ficoll group was 100% compared with the BMAC group, which had 93.4% survival (95% confidence interval, 0.849-1). The difference between the groups was not significant (p=0.381). CONCLUSION: The BMAC system is an effective and suitable "chair-side" method for clinical application in hard tissue regeneration.

Use of the radial forearm artery for secondary embolization of an extensive life-threatening arteriovenous malformation of the mid-face and anterior skull base - a case report.

BACKGROUND: Arteriovenous malformations (AVM) of the head and neck are rare conditions with the majority of primary sites in the mid-face. Progression can lead to massive life-threatening bleeding. Treatment of choice is the combination of embolization and surgical resection. Diagnosis and management of AVM has been facilitated in recent years by the progress in imaging techniques and various microsurgical and endovascular embolization procedures. METHODS: This report presents the interdisciplinary approach to a case of life-threatening AVM of the mid-face in a 30-year-old patient. RESULTS: Angiography with embolization followed by resection and plastic reconstruction was performed. Follow-up showed incomplete obliteration of the AVM and lead to additional embolizations via the anastomosed radial artery. Complete eradication of the AVM was not possible during the three year follow-up period. CONCLUSION: In extensive vascular malformations of the head and neck, complete surgical removal is often impossible and associated with high risk of complications and mortality. Endovascular embolization is limited by the location of the AVM and can potentially cause stroke, ischaemia, necrosis, bleeding, blindness and adverse haemodynamic changes.

Bone marrow aspirate concentrate used with bovine bone mineral to reconstruct vertical and horizontal mandibular defects: report of two techniques.

PURPOSE: Following initial positive reports of the use of bone marrow aspirate concentrate (BMAC) in combination with bovine bone mineral (BBM) in augmentation procedures, the technique was evaluated in patients with mandibular deficiency. MATERIALS AND METHODS: Two adult patients required surgical correction of a deficient alveolar ridge (one patient showed horizontal deficiency only, and the other patient presented with horizontal and vertical deficiency) prior to dental implant placement. In both patients, the reconstruction was performed with BBM in combination with mononuclear cells concentrated by the BMAC method using different techniques. RESULTS: The patients recovered well from all surgical procedures. Histologically, there was uniform bone formation, which allowed placement of dental implants. CONCLUSION: The results suggest that the use of BMAC in combination with BBM, without autogenous bone, has the potential to restore horizontal and vertical mandibular alveolar defects, providing a functional bone structure and allowing dental implant placement for subsequent prosthetic rehabilitation.

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.

Effect of gabapentin-lactam and gamma-aminobutyric acid/lactam analogs on proliferation and phenotype of ovine mesenchymal stem cells.

PURPOSE: Classic tissue engineering consists of three components: scaffold, cells, and growth or differentiation factors. Currently, expensive bone morphogenetic proteins are the most common substance used for hard tissue regeneration. An alternative could be gamma-aminobutyric acid/lactam (GABA-lactam) analogs. MATERIALS AND METHODS: The effects of gabapentin-lactam, cis- and trans-8-tertbutyl-GABA-pentinlactam (trans-TB-GBP-L), and phenyl-GABA-lactam were tested in this study on ovine mesenchymal stem cell (MSC) proliferation. MSCs were selected from bone marrow aspirate concentrate by plastic adherence and amplified. Aliquots of the cells were incubated in medium, with four different concentrations of the GABA-lactam analogs dissolved in dimethyl sulfoxide. Cells in medium with and without dimethyl sulfoxide served as controls. Cell proliferation was tested with a nonradioactive assay. Before and after GABA-lactam analog influence, the MSC character was evaluated by the ability of the cells to differentiate into osteoblasts, chondrocytes, and adipocytes. RESULTS: Proliferation was significantly increased under the influence of the analogs, depending on their concentration. MSCs cultured in 1 nmol/L trans-TB-GBP-L showed the highest proliferation rate. The MSC character was not altered. CONCLUSIONS: GABA-lactam analogs could be suited to stimulate MSC proliferation for tissue engineering applications. Further in vivo studies are necessary to evaluate the possible clinical potential of GABA-lactam analogs for hard tissue regeneration.

Making bone II: maxillary sinus augmentation with mononuclear cells--case report with a new clinical method.

We report a simplified method of using bone marrow aspirate concentrate (BMAC™) to regenerate hard tissue. The results suggest that BMAC™ combined with a suitable biomaterial can form sufficient bone within 3 months for further implants to be inserted, and at the same time minimise morbidity at the donor site.