The anatomical crown of the extracted tooth was

The anatomical crown of the extracted tooth was sectioned off and the screw access hole was created on the palatal surface of the crown (Fig. 7). A screw retained provisional abutment was placed onto the implants. The natural crown was steam cleaned, treated, and connected to the temporary abutment rifampicin with flowable composite resin intra-orally with an aid of a position index (Fig. 8a and b). The connected provisional restoration was then removed from the implant and composite resins were used to contour the sub-gingival portion (Fig. 9a and b). It is crucial the subgingical contour supported the peri-implant tissue.
Upon completion of the screw retained provisional restoration, a tall, flat-contoured healing abutment was placed onto the implant prior to the placement of bone graft materials. The healing abutment allowed the grafting materials to be placed and packed against it at the same time prevented the excess from entering the screw channel. A xenograft bone graft material (Bio-Oss, Geistlich Pharma AG) was used to fill the gap between the implant and the buccal wall as well as the space above up to the most coronal aspect of the free gingival margin (Fig. 10). The healing abutment was then removed, leaving the bone graft material intact. The prepared provisional restoration was subsequently screwed onto the implants and the access was sealed with a temporary material (Cavit temporary filling materials, 3M, ESPE). The occlusion was adjusted to clear all static and dynamic occlusal contacts (Fig. 11). The technique resulted in minimum alteration of the patient׳s esthetics (Fig. 12).

Tooth removal results in marked rifampicin in buccal–lingual alveolar bone width [14,15]. Araujo and Lindhe showed that the reduction of the dimension of an extraction site was due to the replacement of bundle bone with woven bone from the inner portion of the socket and the resorption of the outer and crestal portions of the buccal–lingual socket walls [16].
Various techniques have been proposed to place implants immediately following extraction [17]. Assessment of the morphology of the pre-extraction socket is essential. Elian et al. classified the extraction site based on the presence or absence of the labial and interproximal bone, and its overlying gingival tissue and papilla surrounding the compromised tooth to be extracted [18]. When a socket is not compromised, described as a type I socket, the use of bone graft coupled with flapless surgery can help limit the amount of buccal contour change [11,19,20]. The grafting materials are then contained by the provisional restoration.


The main goal of cleaning and shaping the root canal system is to prepare the root canal, thus creating adequate space for copious irrigation and three dimensional obturation [1,2]. Use of inflexible stainless steel instruments in curved canals can cause iatrogenic damage to the original shape of the root canal [3]. This damage can be in the form of canal transportation, ledge formation or perforation [4]. To avoid recessive damage, nickel titanium (NiTi) instruments with shape memory and superelasticity were developed [5]. But NiTi instruments carry inherent risk of instrument fracture and root dentinal crack formation [6,7]. These root dentinal cracks can further progress to root fractures resulting in failure of root canal treatment [8].
Most commonly NiTi instruments are used with two types of movement: first is continuous rotating full sequence and second is reciprocating. Torsion and flexion occur with continuous rotating NiTi instruments while preparing root canals, which can lead to instrument fracture. To avoid this, reciprocating movement was proposed [9]. This movement minimizes the stresses on instrument by counterclockwise (cutting action) and clockwise (release of instrument) movements [10]. Reciprocating movement claims to mimic manual movement and reduces various risks associated with continuous rotating file systems. But reciprocating systems with small and equal Clockwise (CW)/Counterclockwise (CCM) angles have decreased cutting efficiency, thus making progression into canal more laborious [11].

It is interesting to notice that crystallinity and crystallite size

It is interesting to notice that crystallinity and crystallite size are more for sample prepared using glycine fuel because of solubility of glycine is more compared rifampicin to ODH. This in turn helps in homogeneous mixing of reactants and uniform distribution which results in homogeneous combustion reaction; hence increase of temperature leads to improved crystallization and increased crystallite size. The size differences in both samples may be due to the fuels used for combustion synthesis and also number of gases released during combustion [31].
Rietveld refinement is a method used to estimate the crystal structure of the material using XRD data (FWHM of peaks, asymmetry of peaks, peak shifts, etc.). In the present study the Rietveld method is applied mainly to evaluate the unit cell parameters of the samples. Refinement is done on both ZrO2-1 and ZrO2-2 (Fig. 3). Rietveld refinement is done using the FULLPROF program [32]. We utilize the pseudo-Voigt function in order to fit parameters to the experimental data set. The parameters used are: a scale factor, a zero shifting factor, four back ground factors, three cell parameters, five shapes and width of the peak factors, one global thermal factor and two asymmetric factors. The final refinement analysis shows that the experimental and calculated PXRD patterns obtained by the Rietveld refinement are in good agreement with each other, and all observed peaks have been suitably indexed. For the Rietveld refinement reported, the statistical validity (RBragg) obtained is 3.52 for ZrO2-1 and 3.95 for ZrO2-2, which is well within the permissible limit (∼6). The packing diagram of ZrO2 obtained using Rietveld refinement is shown in Fig. 4. The refined parameters such as occupancy and atomic functional positions of the ZrO2 nanoparticles for both fuels are summarized in Table 2. The fitting parameters (Rp, Rwp and χ) indicate good agreement between the refined and observed PXRD patterns for the ZrO2 nanoparticles.
In present study it rifampicin is evident from PXRD results that in ZrO2-1 a small diffraction peak at 32° corresponding to monoclinic phase was present. However, Rietveld refinement showed pure cubic ZrO2 in both the cases of ZrO2-1 and ZrO2-2. However, this might be due to error in PXRD results are ∼3%. Hence, the phase purity of the samples cannot be precisely determined by PXRD alone in a few cases. Raman spectroscopy is a very sensitive technique and probes molecular and crystal lattice vibrations, and is therefore very sensitive to small changes in crystal structure and bonding. According to the predictions of the factor group analysis, different polymorphs of zirconia have a different number of Raman bands. The monoclinic phase, P21/b(C2h5), has four molecules per unit cell and 18 Raman active modes, 9Ag+9Bg; the tetragonal ZrO2, P42/mnc (D4h15), has two molecules per unit cell and 6 Raman active modes, A+2B+3E. Cubic zirconia with a fluorite structure, Fm3m (Oh5), has four molecules per unit cell and only one Raman active mode, F2.
Fig. 5a and b shows the observed Raman spectra of ZrO2-1 and ZrO2-2 respectively. Raman spectra of the ZrO2-1 show peaks at 147, 264, 318, 457, 473 and 646cm−1. All the peak positions except one at 473cm−1 are quite accordance with the reported values for tetragonal phase of ZrO2[33]. The sharp peak at 473cm−1 corresponds to monoclinic phase of ZrO2[34]. This result confirms the presence of tetragonal and monoclinic phase in ZrO2-1. However, in ZrO2-2 well resolved Raman bands are observed at 149, 268, 320, 457, 616 and 642cm−1. Except for the bands at 540cm−1 and broad band ranging from 595 to 660cm−1 all other peaks are similar to ZrO2-1 and confirms the presence of tetragonal zirconia. The amorphous kind of band at 540cm−1 and broad band at 595–660cm−1 are characteristic bands of cubic phase of zirconia. It is interesting to note that these peaks are absent in ZrO2-1. Similar results were also reported by other researchers in the literature. Kontoyannis et al. [35] also reported that cubic ZrO2 shows amorphous-like Raman spectrum with one broad band at 530cm−1. Basahel et al. reported that cubic ZrO2 exhibit the strong band between 607 and 617cm−1[36]. The reason for the stabilization of cubic phase in this study might be due to oxygen vacancies created during synthesis of ZrO2. This is reasonable because the combustion derived nano-metal oxides have typical oxygen defects [29,37].