Volume 57, Issue 1

One of the conditions for ensuring success in implant surgery with an immediate loading (IL) protocol is to achieve maximum primary stability (PS) through the use of dental implants with the appropriate design and surface and a properly prepared osseous bed. The aim of this study was to assess the stability, degree of osseointegration, and success rate after inserting an implant with IL in an osseous bed prepared with burs or an ultrasonic device. Twenty-five patients requiring single tooth replacement (tioLogic; Dentaurum, Ispringen, Germany) in the aesthetic zone were divided randomly into the test (K0) and control (K1) groups. The following factors were investigated: primary (PS-ISQ) and secondary (SS-ISQ) stability- implant stability quotient (ISQ value) by Ostell Mentor, initial width of the alveolar ridge, marginal bone loss (MBL), and buccal bone thickness. The effectiveness of the implant treatment 1 year after the surgery was 100% for group K0 and 93.3% for group K1. A significant correlation was observed between PS and MBL after 1 month. No statistically significant differences were noted between the groups with regard to MBL after 6 months (K0 0.5±0.4 mm vs. K1 0.8±1.3 mm), PS-ISQ (K0 70±4 vs. K1 71±4), and SS-ISQ (K0 70±2 vs. K1 72±3). The average ISQ value of 70±4 is sufficient to allow for IL. A high level of PS results in lower MBL.

To improve osseointegration, different possible dental implant surface modifications, e.g., alterations of surface chemistry and roughness, have been developed. The purpose of this study was to examine the in vitro biocompatibility of newly designed zirconium implants with different surface modifications in comparison with commercially available zirconium and titanium implants. Therefore, cell viability and proliferation were measured after 21 days and correlated with surface structures. In the presence of new ceramic implants with an “mds (blasted/etched)” and a “blasted” surface, cell viability was 1.29- and 1.26-fold increased, respectively, compared to untreated cells, whereas cell viability was unchanged in the presence of reference implants and new ceramic implants with an “etched” surface. The cell viability findings correlate with the results of the cell cytotoxicity assay. The etched implants showed a surface with high roughness and heterogeneity, whereas the mds and blasted implants showed a similar, very rough-textured homogenate surface. The in vitro biocompatibility of two new ceramic implants was significantly better in comparison with the tested reference ceramic and titanium implants. The good biocompatibility may be attributed to the homogenous surface of these implants, and these surfaces might hasten osseointegration.

The effect of bone remodeling on the long-time success of dental implants is becoming critical for implant design and presurgical assessments. This study applies a previously presented remodeling simulation scheme on a computer tomography (CT)-based finite element model. The CT data of a dental implant at the upper right central incisor region 6 years after implant insertion was used. The time-dependent density change of the trabecular bone after osseointegration was studied. The trabecular structure, by means of density distribution, around the implant showed similarities to the CT images at many regions.

In recent years, mini and short dental implants have become increasingly popular as treatment alternatives for patients in whom the bone is unsuitable for a standard implant. As yet, no detailed scientific analysis of the mechanical and biomechanical impact of the reduced diameter and length of these implants has been published. We analysed 21 commercially available implants (13 mini, eight short) with respect to material behaviour and load transfer to the alveolar bone, using finite element (FE) analysis. Following μCT scanning and geometry reconstruction, FE models of mini implants and short implants were inserted into idealised bone segments. Mini implants were analysed in the anterior mandibular jaw region at a force of 150 N under immediate loading, using a contact analysis in the FE software package Marc Mentat 2007. Short implants were inserted in posterior bone segments and analysed in the osseointegrated state at an occlusal force of 300 N. Von Mises stresses (up to 1150 MPa) in mini implants partly exceeded the ultimate strength. Implant diameter and geometry had a pronounced effect on stresses in the cortical plate (up to 266 MPa). Strains in spongy bone and stresses in cortical bone around short implants were markedly increased compared to those in standard implants. An increased risk of bone damage or implant failure may be assumed in critical clinical situations.

This 2-year study investigates the survival and crestal bone loss of immediately loaded implants used to support complete-arch implant-supported prostheses (ISPs) or tooth-implant-supported fixed prostheses (TISPs) in the maxilla. Six patients with 52 implants for the support of ISPs and seven patients with 22 implants and 24 abutment teeth for the support of TISPs were included. All implants were immediately loaded. The survival of the supporting implants and teeth was evaluated for up to 6 months after immediate loading. Bone loss around the implants was measured using panoramic radiographs. After the first year, TISPs showed less bone resorption (–0.04 mm from the reference level) than did ISPs (–0.1 mm), while no difference was observed after the second year. Considering the number of pontics used for the prostheses, no significant difference was observed between ISPs and TISPs after both 1 and 2 years. Immediate loading could be a protocol of choice for both maxillary ISPs and TISPs.

The aim of this retrospective study was to evaluate the survival rate of implants, abutment teeth, and suprastructures along with the management of the complications for complete-arch, semipermanent cemented tooth-implant-supported restorations in 44 maxillae. Permanent cemented copings protect the prepared teeth from caries. The metal-ceramic fixed dental prostheses (FDPs) were cemented onto copings and implant abutments using acryl-urethane cement. Data were assessed via patient records and a final clinical examination. Six years after cementation, no implant or restoration had failed. After the extraction of two teeth and placement of an additional implant, three restorations had to be subsequently changed (89% of restorations were unchanged after 6 years). The loss of retention without tooth intrusion occurred in two restorations. All 23 restoration removals for prosthetic aftercare were non-destructive. The results of this study indicate that complete-arch, semipermanently cemented FDP rigidly connecting the maxillary teeth and implants are a reliable treatment option.

Objectives: This case series aimed to explore the clinical outcome of sinus floor elevation surgery using a crestal approach technique in case of severely resorbed maxillae. Material and methods: Seventeen edentulous patients received 20 implants and sinus floor elevation in posterior maxillae with residual crestal height of 1.2–5.0 mm and >7 mm. Drilling perforation was performed until the sinus floor was felt; the sinus mucosa was then lifted and magnesium-enriched hydroxyapatite granules (Mg-e HAP) were placed; and implants were immediately inserted. Four months later, definitive crowns were cemented, and patients were followed up for 24 months. Implant failures and complications 24 months after prosthetic loading were noted, and radiographic regenerated bone height was measured. Results: No patient dropped out, and all implants were successfully osseointegrated. There was minimal postoperative patient discomfort, and the only complication was a minimal perforation of the sinus membrane with no negative consequences. At the time of implant insertion, the residual crestal height mean value was 4.12 mm. After surgery and at the last follow-up, the mean heights of bone were 13.51 and 12.98 mm, respectively. Conclusion: The procedure was able to obtain sinus elevation and implant osseointegration.

The modification of flax fibers to create biologically active dressings is of undoubted scientific and practical interest. Flax fibers, derived from transgenic flax expressing three bacterial genes for the synthesis of poly-3-hydroxybutyric acid (PHB), have better mechanical properties than unmodified flax fibers; do not show any inflammation response after subcutaneous insertion; and have a good in vitro and in vivo biocompatibility. The aim of this study was to examine the applicability of composites containing flax fibers of genetically modified (M50) or non-modified (wt-Nike) flax within a polylactide (PLA) matrix for bone regeneration. For this, the mRNA expression of genes coding for growth factors ( insulin-like growth factor IGF1, IGF2, vascular endothelial growth factor ), for osteogenic differentiation ( alkaline phosphatase, osteocalcin, Runx2, Phex, type 1 and type 2 collagen ), and for bone resorption markers [ matrix metalloproteinase 8 (MMP8), acid phosphatase type 5 ] were analyzed using quantitative real-time polymerase chain reaction. We found a significant elevated mRNA expression of IGF1 with PLA and PLA-wt-Nike composites. The mRNA amount of MMP8 and osteocalcin was significantly decreased in all biocomposite-treated cranial tissue samples compared to controls, whereas the expression of all other tested transcripts did not show any differences. It is assumed that both flax composites are able to stimulate bone regeneration, but composites from transgenic flax plants producing PHB showed faster bone regeneration than composites of non-transgenic flax plants. The application of these linen membranes for bone tissue engineering should be proved in further studies.

Background: The oral cavity along with the teeth and the surrounding gingival epithelium is open to the oral environment and is thus exposed to multiple microbiological and pathogenic influences. To prevent permanent inflammatory processes such as gingivitis or parodontitis, an efficient defense system is necessary to sustain the physiological function of the oral cavity. Surfactant proteins (SPs), originally known from pulmonary tissue, are important players of the immune system and, beyond this, support the stability and rheology of gas or fluid interphases. Methods: Here we evaluate the expression and presence of SPs (SP-A, SP-B, SP-C, and SP-D) in human gingiva and saliva. Messenger RNA expression of SP-A, SP-B, SP-C, and SP-D was analyzed by reverse transcriptase-polymerase chain reaction in healthy gingiva. The distribution of all four SPs was further determined with monoclonal antibodies using Western blot analyses and immunohistochemistry in healthy and pathologically changed tissues samples obtained during biopsies and in saliva of volunteers. Results: Our results indicate that SP-A, SP-B, SP-C, and SP-D are peptides produced by healthy gingiva that reveal a changed expression pattern in cases of gingival disease. Conclusion: Based on the known direct and indirect antimicrobial effects, SP-A and SP-D appear to be involved in immune defense within the oral cavity especially in direct proximity of teeth. Gingiva affected by bacterial inflammation (gingivitis) seems to increase expression of SPs. As a result, the rheology of saliva may be changed especially at the crest of the gingival epithelium to support the function of antimicrobial substances present in saliva. Furthermore, SPs could assist in pellicle formation on teeth, which needs to be determined in further experiments.

The objective of the current epidemiological study is to show the correlation of various postural abnormalities and spinal deformities and the clinically identifiable dentofacial anomalies by orthodontic examination. Twenty-three children with Scheuermann’s disease [mean age: 14 years 8 months; standard deviation (SD): 1 year 8 months] and 28 with scoliosis (mean age: 14 years 7 months; SD: 2 years 3 months) participated in the study. Standardized orthodontic screening protocols were used to map the occlusal relations in the sagittal, vertical, and horizontal dimensions; the space relations of the maxillary and mandibular frontal segment; the temporomandibular joint (TMJ) status; and the facial asymmetries. Statistically significant differences (p<0.05) were found between the values of the examined groups of patients for the following measurements: incisal overjet and overbite, upper and lower midline deviation, mandibular frontal spacing, TMJ pathological symptoms and functional characteristics, and frequency of facial asymmetries. A large percentage of patients with pre-pubertal developments of spinal deformities have various dentofacial anomalies. The majority of these anomalies are present in patients with Scheuermann’s disease. Early treatment of the malocclusions closely correlated to postural disorders should minimize the progression of the dentofacial anomalies, making necessary performing orthodontic screening of these patients as early as possible.

Objective: To determine the lingual surface morphology of central and lateral upper incisors evaluating constant morphological regions for better adhesion of industrial prefabricated lingual brackets. Material and methods: A total of 102 randomly selected patients at the end of the first phase of second dentition with intact central and lateral upper incisors participated in this study. After impression taking and cast model preparation, 3D laser scans of the lingual surface of the upper central and lateral incisors were taken (Laserscan 3D ® , Willytec, Munich, Germany), digitalised, and transferred into CAD software to analyse the surface morphology by superimposition. For better comparison of morphological variations and determination of the most constant lingual regions, the surface was divided into five parts: incisal edge, mesial ridge, lateral ridge, cingulum, and medial sector. Statistical analysis was performed by the paired t -test. Results: Statistically significant differences were found in all surfaces, with cingulum as the most inconstant region. The most constant region was the medial sector and the mesial ridge. Conclusion: As expected, the lingual surface underlies a high intra-individual variation complicating industrial prefabricated lingual brackets adhesion. However, the mesial ridge and the medial sector seem to be the most constant regions within intra-individual morphological variations.

No abstract available