Ortiz-Ruiz Aj

Histological and histomorphometric evaluation of immediate implant placement on a dog model with a new implant surface treatment

PURPOSE The aim of this study was to evaluate crestal bone resorption and bone apposition resulting from immediate post-extraction implants in the canine mandible, comparing a conditioned sandblasted acid-etched implant surface with a non-conditioned standard sandblasted implant surface. MATERIAL AND METHODS In this experimental study, third and fourth premolars and distal roots of first molars were extracted bilaterally from six Beagle dog mandibles. Each side of the mandible received three assigned dental implants, with the conditioned surface (CS) on the right side and the non-conditioned surface (NCS) on the left. The dogs were sacrificed at 2 (n=2), 4 (n=2) and 12 weeks (n=2) after implant placement. RESULTS The microscopic healing patterns at 2, 4 and 12 weeks for both implant types (CS and NCS) yielded similar qualitative bone findings. The mean crestal bone resorption was found to be greater for all implants with NCS (2.28+/-1.9 mm) than CS (1.21+/-1.05 mm) at 12 weeks. The mean percentage of newly formed bone in contact with implants was greater in implants CS (44.67+/-0.19%) than with the NCS (36,6+/-0.11%). There was less bone resorption with the CS than the NCS. CONCLUSION The data show significantly more bone apposition (8% more) and less crestal bone resorption (1.07 mm) with the CS than with the NCS after 12 weeks of healing. This CS can reduce the healing period and increase bone apposition in immediate implant placements.

Histomorphometric and mineral degradation study of Ossceram®: a novel biphasic B-tricalcium phosphate, in critical size defects in rabbits

OBJECTIVE To carry out a histomorphometric analysis of a new highly porous (95%) biphasic calcium phosphate (hydroxyapatite 60%/B-tricalcium phosphate 40%), used to fill critical size defects in rabbit tibiae, supplementing histomorphometric findings with radiographic thermal imaging, EDX analysis and Ca/P ratio mapping at different time stages. MATERIALS AND METHODS Two critical size defects of 6 mm diameter were created in both tibiae of 21 New Zealand rabbits, test group (Ossceram) and control group. Histomorphometric, radiographic thermal imaging, EDX and element mapping analysis were performed at 15, 30 and 60 days after graft insertion. RESULTS Histomorphometric analysis at 30 days showed more new bone formation in defects filled with Ossceram 4.41 ± 0.23 mm than the test group 1.94 ± 0. 28 mm (P<0.05). Element analysis revealed higher percentages of Ca (42.33 ± 2.8%) and P (1.3 ± 0.8%) in the test group than in the control group (P<0.05). Element mapping showed that Ca and P were concentrated in medullar and cortical zones in the test group but were concentrated only in cortical zones in the control group. Test group histomorphometry at 60 days showed complete closure of the cortical defect 5.37 ± 0.32 mm more than the control group 2.3 ± 0.54 mm. There was no cortical defect closure or medullar bone formation in the control group (P<0.05). Element analysis revealed higher percentages of Ca (32.26 ± 21.7%) and P (1.5 ± 0.3%) in the test group than in the control group (P<0.05). CONCLUSION Defects of a critical size in a rabbit tibia model can be sealed using a highly porous biphasic calcium phosphate; this supports new bone formation, creates a bridge between borders and facilitates bone ingrowth. Furthermore, this study observed partial dissolution of the mineral phase of the graft material and its incorporation into the surrounding bone. Radiographic thermal imaging may be used to supplement histological and chemical analyses.

Melatonin stimulates the growth of new bone around implants in the tibia of rabbits

Abstract:  This study evaluated the effect of the topical application of melatonin in accelerating bone formation associated with implants 2 months after their application to the tibiae of rabbits. Twenty New Zealand rabbits were used. Twenty implants treated with melatonin and 20 control implants without melatonin were placed in the proximal metaphyseal area of each tibia. Studies of new bone formation were subsequently made at 15, 30, 45 and 60 days. Cortical width and cortical length of new bone formation were measured. Following implantation, an anteroposterior and lateral radiologic study was carried out. Collected samples were sectioned at 5 μm and stained using hematoxylin–eosin, Masson’s trichromic and Gordon‐Switt reticulin stains. After a 60 day treatment period, melatonin increased the length of cortical bone (95.13 ± 0.42%) versus that around control implants (62.91 ± 1.45%). Related to the perimeter of cortical bone of the tibiae, melatonin induced new bone 88.35 ± 1.56% versus 60.20 ± 1.67% in the control implants. Melatonin regenerated the width and length of cortical bone around implants in tibiae of rabbits more quickly than around control implants without the addition of melatonin.

Biological response to porcine xenograft implants: an experimental study in rabbits

Purpose: The aim of this study was to evaluate the effect of a new porcine biomaterial and collagen paste in 20 New Zealand rabbits. Materials and Methods: Forty implants using a porcine xenograft made up of 80% corticocancellous collagenated bone particles of ⩽300 &mgr;m in size were placed in the proximal metaphyseal area of both tibiae. Four periods of time were formed: 1h, 5, 8, and 15 months. After implantation, an anteroposterior and lateral radiological study was carried out. Samples were sectioned at 5 &mgr;m and stained using hematoxylin-eosin, Massons trichromic, and Gordon-Switt reticulin stains. Results: These results confirmed the biocompatibility of this porcine biomaterial-collagen paste; only a few, occasional macrophages and scattered lymphocytes were observed. No fibrosis was observed between the implants and the bone. Moreover, the material was osteoconductive acting as a “scaffold” for bone cells, and there was a progressive increase in bone growth in and around the implants. Conclusion: This new porcine biomaterial-collagen paste seemed to be biocompatible, bioresorbable, and osteoconductive.

Influence of a preventive program on the oral health-related quality of life (OHRQoL) of European pregnant women: a cohort study

The aim of this study was to compare the impact of oral health on quality of life of a group of pregnant women enrolled in a program of oral health with respect to a control group of non-pregnant women. A cross-sectional study involving a sociodental indicator OHIP-14 and a dental examination was completed to assess pregnant women’s knowledge of oral health, hygienic habits, periodontal and caries index. Data were collected from 113 pregnant women and 113 non-pregnant women. Sociodemographic data for both groups were homogeneous. Pregnant women have better values of general and oral health, even though they have not perceived need for dental treatment, compared with control group. A worse periodontal health was observed for the control group. Our results showed that quality of life in pregnant women has been influenced with a statistical significance (p < 0.05) by the variables age, unemployment, level of education, immigration, frequency of brushing, type of dental practice, self-reported general and oral health and perceived treatment needs. The oral quality of life of pregnant women seems to be positively influenced by the incorporation of preventive oral programs during pregnancy.

Structural differences in enamel and dentin in human, bovine, porcine, and ovine teeth

BACKGROUND The aim was to study differences between crystalline nanostructures from the enamel and dentin of human, bovine, porcine, and ovine species. METHODS Dentine and enamel fragments extracted from sound human, bovine, porcine and ovine incisors and molars were mechanically ground up to a final particle size of <100μm. Samples were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). RESULTS Human enamel (HE) and dentin (HD) showed a-axis and c-axis lengths of the carbonate apatite (CAP) crystal lattice nearer to synthetic hydroxyapatite (SHA), which had the smallest size. Enamel crystal sizes were always higher than those of dentin for all species. HE and HD had the largest crystal, followed by bovine samples. Hydroxyapatites (HAs) in enamel had a higher crystallinity index (CI), CIRietveld and CIFTIR, than the corresponding dentin of the same species. HE and HD had the highest CIs, followed by ovine enamel (OE). The changes in heat capacity that were nearest to values in human teeth during the glass transition (ΔCp) were in porcine specimens. There was a significant direct correlation between the size of the a-axis and the substitution by both type A and B carbonates. The size of the nanocrystals and the crystallinity (CIRietveld y CIFTIR) were significantly and negatively correlated with the proteic phase of all the substrates. There was a strongly positive correlation between the caloric capacity, the CIs and the crystal size and a strongly negative correlation between carbonates type A and B and proteins. CONCLUSIONS There are differences in the organic and inorganic content of human, bovine, porcine and ovine enamels and dentins which should be taken into account when interpreting the results of studies using animal substrates as substitutes for human material.