AIMS AND OBJECTIVES:
The present study aims at analysing physicochemical characteristics of 5 different types of
alloplastic graft materials used in periodontal regeneration.
MATERIALS AND METHODS:
The materials used were:- Monophasic Hydroxyapatite – Biograft HA, Tricalcium Phosphate
– Biograft TCP, Biphasic Hydroxyapatite – Biograft HT, Bioactive Glass – Perioglas and a
combination of Hydroxyapatite and Bioactive Glass – Biograft HABG Active.
MATERIAL CHARACTERIZATION:
The physicochemical properties of the biomaterials were tested using the following methods:
1. Scanning Electron Microscopy [SEM] - assess the sample`s surface topography & size
2. Thermogravimetry - reflect divergent physical properties and chemical compositions
among the specimens resulting from their diverse thermal histories.
3. Fourier Transform Infrared Spectroscopy [FTIR] - to provide information concerning the
chemical composition and the major functional groups.
4. X ray diffractometry [XRD] - used to identify phase and composition features and
qualitatively evaluate the crystallinity of the materials
5. Dissolution rates - used to evaluate the solubility rate of calcium and silica
RESULTS:
From the particle size related data it is seen that PG and HA show smaller particles
(100 – 300 μm) while TCP, HT and HABG show larger particles (200 – 500 μm). In the
present study Biograft HA, Biograft TCP and Biograft HABG showed rough and irregular
surface, while Perioglas and Biograft HT showed a smooth surface. The surface of perioglas
is said to be smooth with less roughness, Biograft HT shows smooth and sintered surface
particles with nano pores visible. All the other materials show rough surface with the
presence of micro and nano sized pores ranging from 0.5 – 1 μm. Thermogravimetric
analysis is used to determine the content of water, organic material (like collagen) and
mineral (CaP). For all of the alloplasts in our study only a minimal weight loss upto 2 % was
seen which can be attributed to the presence of moisture or due to oxidation of the samples.
As all the test materials were synthetic or alloplastic, there was the absence of lattice water or
organic content. All the tested materials were stable upto 10000 C, which renders all test
materials to be thermally stable and phase pure and without any impurities. Infra red analysis
shows the presence of main functional groups such as phosphates and carbonates. The
calcium phosphate class of materials (HA, TCP and HT) and HABG showed almost similar
stretching and vibration patterns for both functional groups. Phosphate peak was broad in
Perioglas which may be due to the amorphous nature of material. In the Infrared spectra data
from the 5 tested materials, hydroxyl peaks had highest intensity in HA, with midway values
in HT and almost nil in TCP. HABG does not show a peak corresponding to OH group and
PG shows a broadened peak. X ray diffraction patterns of the 5 alloplastic materials indicate
their chemical composition (presence of crystalline phases) and lattice parameter information.
The XRD peaks of the samples were well defined. Among the 5 alloplastic materials HA,
HABG, TCP and HT showed typical crystalline structure whereas PG showed broad peaks
indicating the amorphous nature of the material. An increasing order of crystallinity was
obtained from XRD data as PG, HABG, TCP, HT and HA. In the dissolution tests done for
calcium, all the materials showed positive results. Bioactive glass class of grafts (PG and
HABG) had more dissolution when compared to hydroxyapatite class (HA,TCP and HT).
The second dissolution test was done for silica, the bioactive glass group of material (PG and
HABG) which are silica based were tested. Both PG and HABG showed increased
dissolution of silica upto 24 hours, with PG showing constant values and HABG showing
decreasing rates after 24 hours.
SUMMARY:
The main objective of present work was the physicochemical characterization of 5 commercial sample of alloplasts used for bone grafting. The alloplastic biomaterials belonged to 3 main classes calcium phosphate group (HA, TCP and HT), bioactive glass group (PG) and a combination graft (HABG). However even for those with similar chemical characteristics, significant differences were noted with regard to particle size, porosity, surface roughness, presence of functional groups, crystallinity and dissolution properties. Among the materials tested calcium phosphate based ceramics and bioactive glass – ceramic combination showed porous surface architecture parameters conducive to cellular and vascular proliferation. Thermogravimetric analysis revealed that all the materials were phase pure with no impurities. Infra red spectrometry showed presence of functional groups essential for bone integration in all test materials with Perioglas and Biograft HABG showing presence of silica which has a beneficial effect in bone formation. X ray diffractometric analysis revealed that with the exception of Perioglas which was amorphous all the other materials were crystalline in nature. Increased dissolution of calcium and silica were seen in bioactive glass group when compared with calcium phosphate and mixed calcium phosphate grafts
