1,721,141 research outputs found
Histological features of peri-implant bone subjected to overload
No full textPurpose: The aim of this review has been to investigate the histological findings of bone structure surrounding implants subjected to excessive load. Materials and methods: Clinical and pre-clinical histological studies that observed overloaded intraoral implants were included. Results: All included studies (n = 15) were conducted on animals. Most of them failed to find pathological alteration in the microstructure of bone surrounding overloaded implants. Overload and infection alone may induce bone loss, but related lesions have different and peculiar features. Conclusions: The different histological features observed around implants subjected to overload or to ligature-induced peri-implantitis may indicate a specific pathogenetic mechanism for overload or infection-induced loss of osseointegration. The clinical significance of these findings should be confirmed in human studies
Maxillary sinus floor augmentation using a nano-crystalline hydroxyapatite silica gel : case series and 3-month preliminary histological results
No full textThe aim of this case series is to histologically examine a new hydroxyapatite in sinus lift procedure after 3 months. Ten 2-stage sinus lifts were performed in 10 healthy patients having initial bone height of 1-2 mm and bone width of 5 mm, asking for a fixed implant-supported rehabilitation. After graft material augmentation, a rough-surfaced mini-implant was inserted to maintain stability of the sinus widow. A bioptical core containing a mini-implant was retrieved 3 months after maxillary sinus augmentation with NanoBone (R) and processed for undecalcified histology. From the histomorphometric analysis, NanoBone (R) residuals accounted for the 38.26%+/- 8.07% of the bioptical volume, marrow spaces for the 29.23%+/- 5.18% and bone for the 32.51%+/- 4.96% (new bone: 20.64%+/- 2.96%, native bone: 11.87%+/- 3.27%). Well-mineralized regenerated bone with lamellar parallel-fibred structure and Haversian systems surrounded the residual NanoBone (R) particles. The measured bone-to-implant contact amounted to 26.02%+/- 5.46%. No connective tissue was observed at the implant boundary surface. In conclusion, the tested material showed good histological outcomes also 3 months after surgery. In such critical conditions, the use of a rough-surfaced mini-implant showed BIC values supposed to be effective also in case of functional loading. Although longer follow-up and a wider patient size are needed, these preliminary results encourage further research on this biomaterial for implant load also under early stage and critical conditions
Histomorphometric analysis of human maxillary sinus lift with a new bone substitute biocomposite : a preliminary report
No full textPURPOSE: To analyze radiographic and histological outcomes of maxillary sinus floor augmentation using a calcium-sulfate based allograft containing demineralized bone matrix particles.
MATERIALS AND METHODS: Fifteen maxillary sinus lift procedures with simultaneous placement of titanium implants were performed in 12 patients of both genders aged 36-71 years. Each sinus cavity was filled by the biocomposite. After 3 months of healing, all surgical sites were uncovered and bone biopsies were retrieved for undecalcified histology and histomorphometry. The ratio between the original and the grafted sinus height (GSH/OSH) was computed using a panoramic radiography taken immediately after surgery and at 3 months of healing, and the two ratios were compared by Wilcoxon signed-rank test.
RESULTS: By 3 months, all implants were stable without clinical and radiographic signs of infection. Significant changes in GSH/OSH during healing were seen (2.7 +/- 0.6 initially vs. 2.6 +/- 0.5 after healing; p = 0.01). Histologic findings showed newly formed bone surrounding the residual grafted particles without inflammation. At 3 months, mean regenerated bone density was 33.8 +/- 8.6%; marrow spaces amounted to 32.3 +/- 10.3%; residual graft was 33.9 +/- 9.0%. Similar histomorphometric and radiographic results were obtained independently from patient age or sex.
CONCLUSIONS: The analysed putty seems to be a safe and effective graft material for maxillary sinus floor augmentation by accelerating bone regeneration and thus reducing the healing time
Evaluation of a resorbable collagen matrix infused with rhPDGF-BB in peri-implant soft tissue augmentation: a preliminary report with 3.5 years of observation
No full textSoft tissue augmentation around dental implants in the esthetic region remains a challenging and unpredictable procedure. The ideal surgical technique would include of an off-the-shelf product to minimize morbidity after autogenous grafting procedures. The aim of this study was to use a resorbable collagen matrix (Mucograft) to serve as a scaffold to recombinant human platelet-derived growth factor BB (rhPDGF-BB) to increase peri-implant soft tissue volume in anterior maxillary sites. A total of six patients who had previously undergone a bone regeneration procedure were included in this study. The collagen matrix was applied during stage-two surgery (expanded polytetrafluoroethylene membrane removal and implant placement). Measurements were performed through customized stents by means of endodontic files, and at abutment connection, a soft tissue biopsy specimen was harvested for histologic examination. The healing period was uneventful in all six patients. Measurements were taken apically, centrally, and occlusally for each site. The mean gains in volume from baseline to the 4-month measurement at the apical, central, and occlusal aspects were 0.87 ± 2.13 mm, 2.14 ± 3.27 mm, and 0.35 ± 3.20 mm, respectively. The results showed a moderate increase in the soft tissue volume in esthetic peri-implant sites when applying a collagen matrix infused with rhPDGF-BB. However, the measuring techniques available need to be further improved to record exact changes in the soft tissue volume
Socket grafting in the posterior maxilla reduces the need for sinus augmentation
No full textThis study compared the dimensional alterations, the need for sinus floor elevation, and the histologic wound healing of augmented and nonaugmented alveolar sockets. Sixteen human extraction sockets were either grafted or left untreated. At baseline and 3 and 6 months postextraction, alveolar ridge alterations were evaluated; at 3, 6, and 9 months, histologic analyses were conducted. Implant placement with or without sinus floor augmentation was decided at 6 months. Three of eight patients in the control group underwent sinus floor augmentation compared to one of six in the experimental group. The alveolar ridge augmentation procedure presented here increases the possibility of inserting implants without the need for a sinus augmentation procedure
Three-dimensional nasal morphology in cleft lip and palate operated adult patients
No full textNasal morphology was assessed three-dimensionally in 18 cleft lip and palate operated patients aged 19 to 27 years, and in 161 sex- and age-matched control subjects. Comparisons were performed by Student t and Watson-Williams' tests. No differences were found in nasal volume or surface. Nasal width, alar base width, and inferior width of the nostrils were significantly larger in male patients than in the reference men. The nasal bridge was shorter. Similar differences were found in the female patients. In addition, the right nostril was larger and the nasal height shorter. In men, the nasolabial and the nasal tip angles were smaller in the patients than in the reference subjects, whereas the facial convexity angle was larger in the patients. In conclusion, the nose of adult operated cleft lip and palate patients differed from that of normal control subjects. Surgical corrections of the cleft lip and palate failed to provide a completely normal appearance. The methods might be used to indicate where additional procedures might be performed to approximate a reference population
ssEMG assessment of a new tool for the management of 3D vertical dimension of occlusion in prosthetic dental rehabilitations: A case report
No full textIn oral rehabilitation the new dental morphology requires changes in the occlusal relations and in case of whole dental arch restoration also the mandibular position can undergo three-dimensional spatial modifications. Overloads and/or altered distributions of the stresses on the temporomandibular joint, teeth and bones may therefore result with not clearly understood consequences. In the present case report a new tool -Vertical Tester- designed to manage the 3D vertical occlusion during an implant retained full mouth rehabilitation was combined with standardized surface electromyographic (ssEMG) analysis in order to respect the masticatory muscle symmetry and coordination. The Authors conclude that the standardized surface electromyography of the masticatory muscles coupled with custom made centric relation registration device is an easy to use procedure to reduce torsional strains on the oral hard structures
Soft tissue facial areas and volumes in individuals with ectodermal dysplasia : a three-dimensional non invasive assessment
No full textThe objective of this study was to supply quantitative information about the facial soft-tissues of a group of patients with hypohidrotic ectodermal dysplasia. The three-dimensional coordinates of 28 soft-tissue facial landmarks were obtained by an electromagnetic digitizer in 11 male and 9 female patients with hypohidrotic ectodermal dysplasia aged 7-41 years, and in 318 healthy individuals of the same age, ethnicity, and sex. From the landmarks, facial areas (eyes, ears, nose, and lips) and volumes (nose and lips) were calculated according to a geometrical model of face. Data were compared to those collected in the normal subjects by computing z-scores. Male and female z-scores were not significantly different. In the pooled sample, the deviations from the norm were particularly evident in the lips, with a significant (Student's t-test, P < 0.05) increment of the total lip area (mean z-score: 0.96) and of the vermilion area of the upper lip (mean z-score: 1.07), a finding negatively related (r = -0.632) to the number of teeth present in the mouth. The eye area was reduced in most patients, a finding significant on the left side (mean z-score: -0.76). Most of the facial areas and volumes of the ectodermal dysplasia patients had z-scores deviating only +/-2 standard deviations from the reference groups. Only 4% of measurements had z-scores larger than +/-3. Additionally, a large inter-individual variability was found, together with a certain age-related trend of improvement of the number of measurements within the +/-2 interval. The method allowed a simple, low cost, fast, and non invasive examination of the patients, and provided a quantitative assessment of the deviation from the norm
- …
