The "puffed cheek method" to evaluate mucosal thickness: case series.

OBJECTIVES: Mucosal thickness should be considered in implant treatment planning. Needle probing to measure mucosal thickness is invasive and therefore not used in routine diagnosis. The "puffed cheek" method is an established technique to visualize the vestibule in computed tomography (CT). As CT assesses bone availability, a simultaneous mucosal thickness measurement would be useful. The aim of this study was to evaluate the reliability of mucosal thickness measurement in CT with distended cheeks. MATERIALS AND METHODS: Buccal maxillary mucosa thickness was evaluated at four measurement sites in the incisor and molar area of 11 patients. Each site was evaluated via CT with cheek distension and needle probing. Measurement area was identified with the aid of a thermoplastic splint to localize the exact position by a gutta-percha marker point. The comparison between the two methods was performed by Bland-Altman diagram. RESULTS: The mean clinical thickness was 1.17 mm (±0.31) compared to 1.11 mm (±0.31) in CT evaluation. The mean difference between the two methods was 0.07 mm (±0.40; CI-0.14;0.12, P = 0.88, Krippendorff α = 0.38). According to Bland-Altman diagram the mucosal thickness may diverge by up to 0.9 mm from the radiologic thickness. CONCLUSIONS: The two measurement methods may not be interchangeably used. As additional information to three-dimensional bone analyses, CT may be performed as a pre-operative soft tissue analysis at most implant sites with distended cheeks. Nevertheless, this method yields less valid and reliable results than the gold standard.

Esthetic evaluation of single-tooth implants in the anterior maxilla following autologous bone augmentation.

OBJECTIVES: Autologous bone augmentation to rebuild compromised alveolar ridge contour prior to implant placement allows for favorable three-dimensional implant positioning to achieve optimum implant esthetics. The aim of the present study was to evaluate peri-implant soft tissue conditions around single-tooth implants following bone grafts in the esthetic zone of the maxilla. MATERIALS AND METHODS: Sixty patients underwent autologous bone augmentation of deficient maxillary sites prior to placement of 85 implants in the esthetic zone. In case of multiple implants per patient, one implant was randomly selected. Objective evaluation of 60 single-tooth implants was performed using the Pink-Esthetic-Score (PES) and Papilla Index (PI) and supplemented by subjective patient evaluation, as well as clinical and radiologic examination. RESULTS: Objective ratings of implant esthetics were satisfactory (median PES: 11, median PI: 2) and significantly correlated with high patient satisfaction (mean VAS score: 80%). Both esthetic indices demonstrated respectable levels of inter- as well as intra-observer agreement. Poor implant esthetics (low PES and PI ratings) were significantly associated with increased anatomic crown height, while no influence of horizontal implant-tooth distance could be found. CONCLUSIONS: The present investigation indicates that favorable esthetic results may be achieved in the augmented anterior maxilla. However, bony reconstruction of compromised alveolar ridges does not guarantee optimum implant esthetics.

Prolyl hydroxylase inhibitors increase the production of vascular endothelial growth factor by periodontal fibroblasts.

BACKGROUND AND OBJECTIVE: Pharmacological inhibitors of prolyl hydroxylases (PHDs) can induce a proangiogenic response that favors wound healing and bone regeneration. However, the response of periodontal cells to PHD inhibitors is unknown. MATERIAL AND METHODS: To determine the effects of PHD inhibitors on periodontal cells, we exposed human fibroblasts from the gingiva and the periodontal ligament to dimethyloxallyl glycine, desferrioxamine, l-mimosine and CoCl(2). Viability, proliferation, and protein synthesis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), [(3)H]thymidine, and [(3)H]leucine incorporation, respectively. The levels of Ki67, hypoxia-inducible factor 1α (HIF-1α), p27, phosphorylated c-Jun N-terminal kinase (JNK) and phosphorylated p38 were determined by immunohistochemistry and western blotting. Vascular endothelial growth factor (VEGF) mRNA levels were measured by quantitative PCR. Protein levels of VEGF and interleukin (IL)-6 were evaluated by immunoassays. RESULTS: We found that PHD inhibitors, while leaving cell viability unchanged, reduced proliferation and protein synthesis. This was paralleled by decreased Ki67 levels and increased p27 levels, suggesting that PHD inhibitors provoke growth arrest. Independently from this response, PHD inhibitors stabilized HIF-1α and increased the production of VEGF. This increase of VEGF was observed in the presence of proinflammatory IL-1 and pharmacological inhibitors of JNK and p38 signaling. Moreover, PHD inhibitors did not modulate expression of IL-6 and the phosphorylation of JNK and p38. CONCLUSION: These results suggest that PHD inhibitors enhance the production of VEGF in periodontal fibroblasts, even in the presence of proinflammatory IL-1. The data further suggest that PHD inhibitors do not provoke a significant proinflammatory or anti-inflammatory response in this in vitro setting.

Atrophy of the residual alveolar ridge following tooth loss in an historical population.

OBJECTIVES: To study the natural aetiopathology of jaw atrophy after tooth loss, unaltered by prosthetic procedures, an historical population without modern dental treatment was examined. METHODS: Based on the hypothesis that there are predictable changes in shape during jaw-atrophy, frequency and degree of atrophy as well as clinical aspects of bone quality and resorption were determined in the skeletal remains of 263 individuals. The potential association between age and frequency/severity of atrophy was analysed. RESULTS: Atrophy in at least one jaw segment was present in 45.2% of the analysed jaw specimens. The residual ridge underwent a series of changes in shape and height following the pattern of resorption described for modern populations. The severity of these alterations was associated with the age of the individual and the region within the jaw. Atrophy was frequently related to structural degradation of the covering cortical layer. CONCLUSIONS: These findings prove that atrophy of the jaw evidently does occur, displaying similar patterns of resorption in a population without modern prosthetics, where the negative effect of ill-fitting dentures is excluded. The basic information about alterations of shape and the cortical layer covering the residual crest might help to provide a deeper insight into aetiopathological mechanisms of this common oral disease.

The response of dental pulp-derived cells to zoledronate depends on the experimental model.

AIM: To investigate whether zoledronate (ZOL) can cause a cytotoxic response in dental pulp-derived cells (DPCs) in vitro. METHODOLOGY: Cell activity was assessed utilizing MTT tests, (3) [H]thymidine, and (3) [H]leucine incorporation assays in human DPCs in response to ZOL. Cell activity assays were also preformed on calcium phosphate-coated plates. Cell death was analysed with annexin V/propidium iodide, trypan blue staining and Western blot analysis. RESULTS: Micromolar concentrations of ZOL were required to decrease the activity of DPCs. The decreased activity of DPCs was associated with the occurrence of apoptosis and necrosis. No adverse effects were observed when DPCs were cultured on calcium phosphate-coated plates with ZOL. CONCLUSION: High concentrations of soluble ZOL were required to cause adverse effects in vitro. These adverse effects are abolished when the bisphosphonate was bound to a mineralized surface. However, the clinical relevance of these results remains to be determined.

Caries frequency and distribution in an early medieval Avar population from Austria.

OBJECTIVE: The aim of this study was to determine frequency and distribution of dental caries in an early medieval Avar population from Central Europe, namely Vienna. METHODS: The evaluation of caries was carried out in an anthropological sample consisting of the remains of 136 individuals and included 2215 permanent teeth. Age and sex estimations were based on dental development and on skeletal ageing methods. The presence of dental caries was determined according to clinical aspects using a dental probe. RESULTS: The frequency of ante mortem tooth loss in the sample was 23.8%; the total caries frequency was calculated as 14.9%. The highest caries rate was recorded in the second mandibular molar (34.6%). The most affected tooth surface was found to be the root with 12.7%, followed by the approximal surface with 8.6%, but only 7.7% of the occlusal surfaces were affected by caries. CONCLUSION: This study revealed that Avars suffered from higher caries rates than most other medieval European populations, but experienced a similar dental caries distribution. Attrition of the occlusal surface resulting from a diet containing abrasive particles with accompanying posteruptive tooth movement is considered the major factor causing this premodern caries pattern.

Activated platelets increase proliferation and protein synthesis of human dental pulp-derived cells.

AIM: To evaluate the impact of activated platelets on the mitogenic expansion of human dental pulp-derived cells (DPC) in vitro. METHODOLOGY: The effect of supernatants released from activated platelets (PRS) and the corresponding platelet membranes (MEM) on proliferation and protein synthesis of DPC was evaluated. The contributions of the phosphoinositide 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) pathways to the response of DPC were assessed using kinase inhibitors. Also examined was whether the presence of calcium hydroxide or the inflammatory mediators tumour necrosis factor alpha, interleukin-1, interleukin-6 and lipopolysaccharide of Escherichia coli modulated the expansion of DPC. RESULTS: Physiologic concentrations of PRS and MEM stimulated proliferation and protein synthesis by 18.4-fold (P < 0.01) and 2.9-fold (P < 0.01), respectively. This mitogenic expansion was paralleled by activation of AKT and the MAP kinases extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38. Inhibitor studies revealed that the mitogenic response of DPC involved PI3K/AKT, JNK and p38 signalling (P < 0.05). Calcium hydroxide and inflammatory factors did not significantly modulate the mitogenic response of DPC to PRS and MEM. CONCLUSION: Supernatants released from activated platelets and the corresponding platelet membranes stimulated DPC proliferation and protein synthesis involving PI3K/AKT and MAPK signalling. These findings may serve as a basis for preclinical studies that address the role of activated platelets in dental pulp repair.

Trabecular bone structures in the edentulous diastema of osteoporotic sheep.

The edentulous ovine diastema represents a suitable region for implantological research. Due to distinctive embryonic origin and mechanical loading, the edentulous diastema may respond differently to osteoporosis than tooth-bearing areas. To test this assumption, we subjected geriatric sheep to ovariectomy, calcium-/vitamin-D-restricted diet, and methylprednisolone administration. Adult control sheep remained untreated. Structural parameters and bone mineral density were determined by microcomputed tomography and conventional computed tomography, respectively. We report that the trabecular microstructure in the diastema was preserved from catabolic changes. In contrast, the premolar maxillary region of osteoporotic sheep had diminished trabecular bone mineral density, with the corresponding structural deteriorations. These results suggest that maxillary trabecular bone of the edentulous diastema does not respond to catabolic changes which occur in the tooth-bearing area in osteoporosis. Our findings imply that regional anatomic domains must be considered in the planning of pre-clinical studies, taking osteoporotic changes into account.

Effects of platelet-derived growth factor isoforms on plasminogen activation by periodontal ligament and gingival fibroblasts.

BACKGROUND AND OBJECTIVE: Platelet-derived growth factor isoforms and components of the plasminogen activator system are expressed at higher levels during periodontal regeneration. Recombinant platelet-derived growth factor-BB is approved for the treatment of periodontal defects. In the present study we investigated the effect of platelet-derived growth factor isoforms on the plasminogen activator system in periodontal fibroblasts. MATERIAL AND METHODS: Human periodontal ligament fibroblasts and gingival fibroblasts were exposed to platelet-derived growth factor isoforms. Changes in urokinase-type plasminogen activator, tissue-type plasminogen activator, plasminogen activator inhibitor-1 and plasminogen activator inhibitor-2 transcript levels by platelet-derived growth factor-BB were monitored with a quantitative reverse transcription-polymerase chain reaction. Urokinase-type plasminogen activator and plasminogen activator inhibitor-1 protein levels were assessed by immunoassays. The effects of platelet-derived growth factor-BB on mitogen-activated protein kinase and phosphoinositol-3 kinase/Akt signaling were investigated by western blot and inhibitor studies. Casein zymography and kinetic assays revealed the size and activity, respectively, of the plasminogen activators. RESULTS: We found that incubation of periodontal ligament fibroblasts and gingival fibroblasts with platelet-derived growth factor-BB resulted in enhanced levels of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 transcripts, but not of tissue-type plasminogen activator and plasminogen activator inhibitor-2. Platelet-derived growth factor-BB also increased urokinase-type plasminogen activator and plasminogen activator inhibitor-1 release into the culture medium. Phosphorylation of extracellular signal-regulated kinase, p38, c-Jun N-terminal kinase and Akt was observed in fibroblasts of both origin. Inhibition of phosphoinositol-3 kinase signaling abrogated the platelet-derived growth factor-BB effect on plasminogen activator inhibitor-1 production. Casein zymography revealed enzymatic activity of the urokinase-type plasminogen activator in cell-conditioned media and lysates of periodontal ligament fibroblasts and gingival fibroblasts. Exposure of gingival fibroblasts, but not of periodontal ligament fibroblasts, to platelet-derived growth factor isoforms moderately increased total plasminogen activation in the medium. CONCLUSION: These findings suggest that periodontal ligament fibroblasts attempt to maintain an equilibrium of the plasminogen activator system in the presence of platelet-derived growth factor isoforms.

Dental pulp fibroblasts contain target cells for lysophosphatidic Acid.

Lysophosphatidic acid (LPA) is a locally produced bioactive phospholipid which is involved in tissue repair. The objective of this study was to determine whether dental pulp tissue also responds to the phospholipid. Effects of LPA on proliferation, differentiation, and mitogen-activated protein kinase (MAPK) signaling of dental pulp fibroblasts (DPF) were examined in vitro. We report that DPF express LPA receptors LPA1, LPA2, and LPA3 and respond to the ligand with increased mitogenic activity. Involvement of extracellular signal-regulated kinase, p38 MAPK, and c-Jun NH(2)-terminal kinase in LPA signaling could be demonstrated by use of specific inhibitors and detection of the phosphorylation status of the kinases. An increased mitogenic activity paralleled a decreased number of alkaline-phosphatase-positive cells and expression levels of dentin sialophosphoprotein and osteocalcin. Together, these results suggest that dental pulp fibroblasts can respond to LPA, a process that may play a role in pulp tissue repair.

[Dental magnetic resonance tomography (dental MRI) as a method for imaging maxillo-mandibular tooth retention structures]. / Dentale Magnetresonanztomographie (Dental-MRT) als Verfahren zur Darstellung des maxillo-mandibulären Zahnhalteapparates.

PURPOSE: To establish a new method for dental imaging using magnetic resonance tomography named Dental-MRT and to demonstrate its usefulness in diagnosing dentogen pathologies of the mandible and maxilla. METHODS: Seven healthy volunteers, three patients with pulpitis, two patients with dentigerous cysts, two patients after tooth transplantation, and three patients with atrophic mandibles have been evaluated. Optimized axial T1- and T2-weighted gradient echo and spin echo sequences in 2D and 3D technique have been established to perform studies of the jaws. The acquired images were reconstructed with a standard dental software package on a work-station as panorama and cross-sectional views of the mandible or maxilla. RESULTS: The entire maxillo-mandibular bone, teeth, dental pulp, and the content of the mandibular canal were well depicted. Patients with pulpitis demonstrate bone marrow edema in the periapical region. Dentigerous cysts and their relation to the surrounding structures are clearly shown. After contrast media administration marked enhancement of the dental pulp can be demonstrated. CONCLUSION: Dental-MRT promises to provide a new tool for visualization and detection of dental diseases.

Treatment of a patient with severe osteoporosis and chronic polyarthritis with fixed implant-supported prosthesis: a case report.

This article reports the treatment and 5-year follow-up of an 80-year-old female with a history of severe osteoporosis and chronic polyarthritis. Treatment included methotrixate disodium and acemetacin. After the last tooth was removed from the mandible, the patient was successfully treated with a fixed mandibular prosthesis supported by 6 implants placed between the mental foramina. The implants have remained osseointegrated, and peri-implant smears have been negative for bacterial colonization. Radiographic follow-up examination has revealed bone loss that is slightly greater than expected. This article focuses on the placement of implants in a patient receiving medication for chronic polyarthritis and osteoporosis.

Effects of drill cooling and bone structure on IMZ implant fixation.

Alternating use of the original method of internal drill cooling with manual external cooling, one IMZ implant was placed in the diaphysis (compact bone) and metaphysis (spongy bone) of the left distal tibia in each of six sheep. After polyfluorochrome sequential labeling, two animals survived for 4, 8, and 16 weeks without functional loading of the implants. The drill holes and bone-implant reactions were evaluated in undecalcified ground sections and microradiographs, using computer-aided histomorphometry. At least 30% of all drill holes were incongruent, but up to 25% of the implant surfaces had primary bone contacts. Four weeks after implantation, distinct differences in the bone reactions could be determined between the experimental conditions. After both cooling methods, osteoclastic resorption had extended up to 0.5 mm into peri-implant compact bone and up to 0.18 mm into spongy bone. Based on the percentage of newly formed bone-to-implant contacts, external cooling proved superior at all superficial drill hole levels in compact bone and in all spongy bone beds, while internal cooling was only better at the deeper drill hole levels in compact bone. After 8 and 16 weeks, peri-implant bone remodeling led to further increased new bone-implant contacts, irrespective of incongruent drill holes or cooling methods. At all time periods, abraded titanium particles were observed within interfacial foreign body cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Implant-surgical and prosthetic rehabilitation of patients with multiple dental aplasia: a clinical report.

The expanded experience with oral implants and supplementary augmentation techniques has opened new possibilities for treating patients with oligodontia or anodontia with fixed prostheses. A problem in treating such patients is the need to place implants in growing maxillae or mandibles, as many of these patients are children or adolescents. When implant treatment is postponed until the patient is full grown, dysfunctions become manifest, which necessitates extensive surgical measures to achieve a fixed prosthetic restoration. This report illustrates the problems associated with different concepts for the treatment of multiple aplasia with implants. The results are based on the findings of 22 patients with oligodontia who underwent surgical treatment and were followed over a period of 5 years. Two controversially treated cases are presented.

Lethal photosensitization, autogenous bone, and e-PTFE membrane for the treatment of peri-implantitis: preliminary results.

This clinical study reports on the results of a new method in the treatment of peri-implantitis. The surfaces of 24 plasma flame-sprayed cylindric implants in 17 patients who were diagnosed with peri-implantitis were decontaminated with a combination of toluidine blue (100 micrograms/mL) and laser irradiation at a wavelength of 906 nm. Bone defects were filled with autogenous bone using e-PTFE membranes for retention of the grafting material. Premature membrane exposure occurred in all patients after an average of 3 weeks (+/- 10 days), which required immediate removal of the exposed membrane in 1 patient. Since the soft tissue showed minimal signs of inflammation, the membranes were left in situ for another 6 weeks in all other patients. The mean radiographic peri-implant bone gain was 2 mm +/- 1.90 mm after 9.5 months (maxilla 2.5 mm +/- 2.38 mm; mandible 1.9 mm +/- 1.87 mm). Two implants around which the initial bone defect had already reached the basket had to be removed after 10 months and 35 months, respectively, despite radiographic evidence of improvement of the peri-implant defect. The longer the membrane stayed in situ, the more bone was gained, as long as the membrane was covered by soft tissue (P = .01). However, the longer an exposed membrane was left in place, the smaller the resultant bone gain (P = .0001). Therefore, despite the absence of clinical signs of inflammation, exposed membranes should be removed immediately. The short-term results of this study corroborate the efficacy of the applied treatment method in prolonging the service time of dental implants involved with peri-implantitis.

Experimentally induced peri-implantitis: a review of different treatment methods described in the literature.

The aim of this article was to present the experimental peri-implantitis models described in the literature and to provide a review of currently used treatment methods. For this purpose, 29 English- and German-language studies published in internationally reviewed journals were examined for similarities and differences regarding animal models, types of implants, and methods used for inducing peri-implantitis. In almost all studies, the implants were located in the mandible, which suggests that peri-implantitis of the maxilla has been researched very little. While in most studies, peri-implantitis was induced by means of ligature and plaque accumulation, only 3 studies have been published that attempted to induce peri-implantitis by means of mechanical overload. Of the latter, only one author observed peri-implant bone resorption. Eleven studies reporting on ligature-induced peri-implantitis presented enough data to be subjected to further statistical data analyses. Meta-analysis revealed that the period of ligature application, and thus the duration of plaque accumulation, generally had no influence on the resultant depth of the bone defect. However, when screw-type and cylindric implants were analyzed separately, a weakly significant positive effect of the duration of ligature application on the resultant defect depth was determined for cylindric implants (P = .092). This could imply that smooth screw-type implants were less susceptible to ligature-induced peri-implant inflammation. Regenerative treatment methods included the membrane technique using non-resorbable membranes (guided bone regeneration), augmentation with autogenous bone, augmentation with bone substitute materials (hydroxyapatite or demineralized freeze-dried bone) or with recombinant human bone morphogenetic protein-2, and a combination of membrane and augmentation procedures. While all described methods resulted in acceptable bone gain, it seems to be difficult to achieve new osseointegration (reosseointegration) of treated implants. Of all tested treatment methods, the combination of guided bone regeneration and augmentation with demineralized freeze-dried bone resulted in the most favorable results regarding bone gain and reosseointegration.

A distraction abutment system for 3-dimensional distraction osteogenesis of the alveolar process: technical note.

To date, distraction osteogenesis has been carried out exclusively with devices that allow distraction in one given direction only. However, the new distraction abutment system described in this article allows distraction in any functionally or esthetically desired direction following osseointegration of 1 or several implants, provided that there are adjacent teeth or other osseointegrated implants. With this abutment system, an implant fixed in a position dictated by available bone volume can be moved into a prosthetically desirable position following segmental osteotomy. Accordingly, it also allows correction of the position of implants that were placed at an early age but whose position has changed as the result of jaw growth. Compared with conventional augmentation techniques carried out before or after implant placement, this method should lead not only to a shorter overall treatment time, but also to reduced strain on the patient and better long-term prognosis for success of implants.

Immediate and delayed implantation for complete restoration of the jaw following extraction of all residual teeth: a retrospective study comparing different types of serial immediate implantation.

From April 1986 to September 1993, 134 implants (97 immediate implants, 26 early secondary immediate implants, and 11 late secondary implants) were placed in 20 patients following extraction of all residual teeth. After a mean follow-up period of 27.1 months, the implants were analyzed with regard to peri-implant soft tissue parameters and bone resorption. When the examination was performed, 131 implants (97.7%) were found to be functioning successfully. The mean pocket depths varied between 1.3 and 2.6 mm, and the peri-implant bone resorption showed values between 0.5 and 1.3 mm. Fixed and removable prostheses revealed equal results with regard to the parameters examined. The results of the present study indicate that serial immediate implantation can be considered to be a very promising implant treatment modality for serial teeth extraction, if specific parameters are taken into account.

Incidence and suggested surgical management of septa in sinus-lift procedures.

A variable number of septa, also referred to as Underwood's septa, divide the floor of the maxillary sinus into several recesses and may thus cause various complications during sinus-lift procedures. The incidence of Underwood's septa was evaluated by examining 41 edentulous maxillas. In 13 of these maxillas (31.7% of the cases), sinus floors with at least one septum were observed. Most of the septa were located in the region between the second premolar and the first molar. A possible cause of septal formation could be the variable phases of maxillary sinus pneumatization of the empty alveolar process following tooth extraction.

Survival of 1,920 IMZ implants followed for up to 100 months.

A total of 1,920 IMZ implants, placed between March 1984 and December 1993, were evaluated retrospectively. The Kaplan-Meier cumulative survival rate of the implants was 89.9% after 60 months and 83.2% after 100 months. Life table analysis revealed a statistically significantly lower cumulative survival rate for maxillary implants (71.6% at 60 months and 37.9% at 100 months) than for mandibular implants (90.4% at 100 months). Implants placed in the anterior region of the maxilla failed significantly more often than those placed in the posterior region. This was not observed in the mandible. The age and sex of the patients, the status of the jaw (edentulous, partially edentulous), the time of implant placement in relation to tooth extraction, and the length and diameter of the implants had no statistically significant influence on the cumulative survival rate.