Mesial Side Research Articles

The effect of incomplete crown ferrules on fracture resistance and the failure modes of endodontically treated maxillary incisors restored with cast posts, cores, and crowns

Introduction: The purpose of this study was to investigate fracture resistance and the fracture modes of endodontically treated teeth restored with cast posts and cores in the presence of various configurations of incomplete ferrules. Materials and Methods: Fifty maxillary anterior teeth were endodontically treated and divided into five groups (n = 10) according to ferrule design: group complete ferrule (CF) had a 2-mm circumferential ferrule; group buccal-mesial-palatal (BMP) had a 2-mm ferrule on the buccal, mesial, and palatal sides; group P had a 2-mm ferrule only on the palatal side; group B had a 2-mm ferrule only on the buccal side of the tooth; and group no ferrule (NF) had no ferrule. Each tooth was restored with a cast post, core, and a Ni–Cr crown. All specimens were lingually loaded at 135° to their long axis in a universal testing machine until fractured. Fracture patterns were recorded. Data were analyzed using one-way analysis of variance and Tukey’s honestly significant difference (Tukeyi?½s HSD) test (α = 0.05). Results: The highest load to fracture was CF (534.33 ± 100.30 N), followed by BMP (467.71 ± 54.54 N), P (462.71 ± 54.92 N), B (330.48 ± 54.86 N), and NF (275.93 ± 28.35 N), respectively. There was no statistically significant difference in load to fracture among CF, BMP, and P and between B and NF (P > 0.05). Conclusion: A tooth with incomplete ferrule had lower fracture resistance than one with complete ferrule, but it was still higher than one with no ferrule. The presence of a palatal ferrule was more effective than a buccal ferrule in providing fracture resistance to palatal occlusal loads.

Evaluation of Peri-Implant Bone Reduction Levels from Superimposition Perspective: Pilot Study among Ukrainian Implantology Practice

Objective: To evaluate the possibility and efficiency of using adapted peri-implant bone evaluation method based on the principle of graphical superimposition and compare it to the possibilities of using sagittal sections of CBCT results to register the dynamics of peri-implant bone changes during the first year of implant functioning. Material and Methods: 108 pairs of DICOM data sets were selected and pre-anonymized and coded in Planmeca Romexis ® Viewer software. Each pair of datasets consisted of a CBCT file, obtained immediately after the installation of a dental implant, and one year after its operation. The first method of peri-implant bone changes evaluation was carried out by analyzing the sagittal sections of the CBCT data from the mesial and distal sides of the implant. The second method was followed by original algorithm, which included specific steps of superimposition of graphical images. Results: Superimposition method helped to establish volumetric parameter of circular bone reduction around dental implants after 1 year of their functioning. Such average values for the maxillary distal implants were 3.547 mm3, maxillary frontal implants – 3.118 mm3, mandibular distal implants – 2.614 mm3, mandibular frontal implants – 2.456 mm 3. Correlation values between averages of vertical bone loss parameters and volumetric bone loss parameters riches r=0.954. Among all patients the highest peri-implant bone reduction rates were observed in the distal and frontal areas of the maxilla, even though statistical difference among such parameters of implants installed at the areas of mandible and maxilla was not significant (p > 0.05). Such observation was established during the analysis of results obtained both by digital sagittal cross section from CBCT results and by superimposition method. Conclusion: Using the superimposition principle allows us to evaluate the individual indicator of volumetric bone loss at the peri-implant region. The possibility of taking into account the parameters of bone tissue volume reduction, instead of just geometrical parameter of bone height, allows to individualize the parameters of bone loss among patients of different prosthetic rehabilitation group.

Patient Satisfaction and Marginal Bone Loss Of Different Treatment Modalities Of Mandibular Kennedy Class II Cases

Objectives: This research was carried out to evaluate patient satisfaction and marginal bone loss of different treatment modalities (using double OT attachment, double OT with posterior implant and conventional partial denture) of Kennedy class II cases.Materials and Methods: Totally, twenty-one patients with unilateral distal extension partially edentulous lower arches were randomly assigned into three groups (Group A, B&C). Group (A): patients were rehabilitated with removable partial denture retained by unilateral double OT attachment. Group (B): patients were rehabilitated with removable partial denture retained by unilateral double OT attachment and a dental implant placed in a second molar area with 3.7 mm diameter and 10 mm length. Group (C): patients were rehabilitated with a conventional removable partial denture. Patients were selected with following criteria: Patients with mandibular Kennedy class II with the second premolar as last standing abutment, The remaining teeth should be free from periodontal diseases , Patients should exhibitied sufficient interarch space, with healthy supporting structures and abutments with 1:1.5 crown root ratio, and should have sufficient bone height > 12mm and bone width > 6mm for implant placement. In this study, marginal bone height changes around premolar teeth were evaluated at the time of prostheses insertion, six months and one year later and patient satisfaction was evaluated one month after insertion. Results: Insignificant difference was detected between the three groups at the different follow-up intervals, regarding marginal bone loss. After one year follow up, bone loss was 0.17±0.04, 0.14±0.054 mm for group A, 0.09±0.05, 0.11±0.043 mm for group B and 0.15±0.034, 0.13±0.044 mm for group C on the distal and mesial sides of the second premolar respectively. On the other hand, regarding ease of cleaning, group C showed higher median value (86) compared to group A (64) and group B (51) and Kruskal Wallis test showed sig difference between group C and group B. Overall patient satisfaction and comfort during eating group A and group B showed statistically significant higher median value compared to group C and Kruskal Wallis test showed signigcant difference between group C and other groups. Conclusion: Within the limitations of this study, it could be concluded that for unilateral partially edentulous patients, all the treatment modalities constructed in this study are reliable options regarding marginal bone loss, but for overall patient satisfaction and comfort with eating, unilateral partial dentures retained by double OT attachment with or without posterior implant are better than conventional removable partial dentures however regarding ease of cleaning conventional partial dentures showed better results.

Evaluation of Effect of Connector Designs in Implant Tooth-supported Fixed Partial Denture: A Two-dimensional Finite Element Analysis

The aim of this study was to evaluate the effect of connector designs on scale and distribution pattern of the stress generated in the supporting bone of implant tooth-supported three-unit fixed partial denture in distal extension situation. Three-unit fixed partial denture geometric models with implant abutment in second molar, pontic in first molar, and second premolar as mesial abutment in distal extension situations were evaluated using a two-dimensional (2D) finite element analysis. Three models were designed and constructed with mesial and distal rigid connectors, mesial nonrigid connector, and distal nonrigid connector respectively, using the software ANSYS, version 10.0 (University Intermediate). The models were analyzed to determine the maximum equivalent von Mises stress at five critical zones (maximum value) under static axial loading (240 N) after meshing and assigning the material properties. The maximum stress concentration values at mesial and distal alveolar crest of the implant-supporting bone were 60.59 and 68.57 MPa, respectively, in Model No 1. The high equivalent von Mises stress concentration values at the mesial and distal alveolar crest of the implant-supporting bone were 1.65 and 0.747 MPa with 0.1 mm vertical movement and 7.88 and 9.34 MPa with 0.5 mm vertical movement of the connector respectively, in Model No 2. The high equivalent von Mises stress concentration values at mesial and distal alveolar crest of the implant-supporting bone were 10.45 and 3.43 MPa with 0.1 mm vertical movement and 4.50 and 5.71 MPa with 0.5 mm vertical movement of the connector respectively, in Model No 3. In the supporting bone around the implant in Model No 1, the maximum von Mises stress concentrations were displayed in the crestal zones. In the supporting bone around the implant abutment, the von Mises stress concentrations were minimal toward the apical third zone in all the models. The stress concentrations were minimal in the supporting bone around the implant and the natural tooth in the models with nonrigid connector. When implant is used as distal abutment in three-unit implant tooth-supported fixed partial denture with pontic at first molar in distal extension situation, it is recommended to place the nonrigid connector in the mesial side of the distal implant abutment.

Error analysis of 3D printing surgical guide according to tooth position

The purpose of this study is to evaluate the accuracy of digital surgical guide according to implant position. Dentiform with D2 bone density, which has a #15, 16, 17, 24, 25, 26, 34, 35, 36, 45, 46, 47 edentulous space, is fabricated. Model scanning and cone beam computed tomography (CBCT) data was taken and overlapped using In2Guide software, and the implants were planned. The digital surgical guide was fabricated using 3D printing and the implants were installed using the surgical stent. CBCT were retaken after the implants were installed, and the “before” surgery and “after” surgery CBCTs were overlapped. Then, the degree differences and length differences at implant shoulder and tip area were statistically analysed. The mesial implant of the tooth-supported type showed 1.06±0.53°, 0.29±0.19 mm, 0.39±0.24 mm, the middle implant showed 1.36±0.67°, 0.40±0.15 mm, 0.42±0.23 mm and the distal implant showed 1.39±0.69°, 0.59±0.29 mm, 0.67±0.41 mm respectively. The mesial implant of the tissue-supported type showed 1.76±0.83°, 0.57±0.29 mm, 0.88±0.31 mm, the middle implant showed 2.15±0.65°, 0.69±0.25 mm, 1.08±0.28 mm. and the distal implant showed 2.83±1.17°, 1.09±0.50 mm, 1.34±0.45 mm. The greater the proximity of the implant to the mesial side, the smaller the error.

Adrenal venous sampling as used in a patient with primary pigmented nodular adrenocortical disease

Background: Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause for hypercortisolism, and it diagnosis is highly challenging as the symptoms are often mild and the patients usually visit doctors long after the onset of their symptoms. Methods: Present herein is a rare case of PPNAD which was diagnosed thanks to adrenal venous sampling. A 21-year-old woman presented with centripetalism lumbodynia, hypertension, osteoporosis, and amenorrhea. Plasma cortisol concentrations were elevated, and there was a loss of circadian rhythms. Laboratory reports indicated her plasma adrenocorticotropic hormone (ACTH) as normal and brain imaging showed no delayed enhancement in the saddle region of the pituitary gland, confirming a diagnosis of ACTH-independent Cushing’s syndrome. Enhancement CT scan showed tiny nodules on her left adrenal gland. Adrenal venous sampling (AVS) discoverer elevated plasma cortisol in left adrenal vein and the left part of the inferior vena cava mesial side, indicating increased cortisol secretion in the left adrenal. Results: Following an adrenalectomy taken on her left adrenal, immunohistochemistry revealed PPNAD on the left adrenal. Conclusions: Adrenal venous sampling contributes to the diagnosis of PPNAD and that of Cushing’s syndrome as well. Adrenal venous sampling, an effective diagnostic of PPNAD, proves useful in diagnosis of Cushing’s syndrome.

Comparison between peri-implant bone level changes of implants placed during and 3 months after iliac bone grafting

The aim of this study was to compare the peri-implant bone level changes of implants placed during and 3 months after bone grafting from the iliac crest. A total of 103 implants were placed: 42 during the grafting and 61 at 3 months after the grafting procedure. All patients were grafted with iliac bone from the anterosuperior iliac crest. Bone resorption was evaluated with cone beam computed tomography in all patients at their last control visit. Periodontal health was assessed via the gingival and plaque indices and pocket depths around the dental implants. Mean bone resorption values at the buccal, lingual, mesial, and distal sides of the implants were 1.08 mm, 0.36 mm, 0.30 mm, and 0.25 mm, respectively, in the delayed group, and 1.87 mm, 1.25 mm, 0.92 mm, and 1.23 mm, respectively, in the simultaneous group; the differences between the groups were significant. There were no significant between-group differences in the gingival or plaque indices or pocket depths. The mean follow-up period was 29 months. For reconstructing atrophic jaws, bone grafting from the iliac crest and implant placement after 3 months is a reliable technique with a high success rate and less bone resorption.

Protein and mRNA expressions of IL-6 and its key signaling factors under orthodontic forces in mice: An in-vivo study.

The purpose of this study was to investigate the mechanical loading-induced changes in protein and mRNA expressions of interleukin-6 (IL-6) and its key signaling factors glycoprotein 130 (gp130), signal transducer and activator of transcription 3 (STAT3), and the Src homology phosphotyrosine phosphatase (SHP2) at the tension and compression sides of the teeth in mouse models. A total of 55 C57B/6 mice (10weeks old) were divided into 3 groups. Orthodontic force was applied in group A (experimental group, n=30); the tooth movement device was placed without activation in group B (sham control group, n=15), and group C (blank control group, n=10). Tooth movement was induced by a nickel-titanium coil spring inserted between the maxillary left incisor and the first molar with a force of approximately 4g. The animals were killed 12days after the interventions; protein and mRNA expressions of IL-6, gp130, STAT3, and SHP2 in the periodontal tissues were observed with immunohistochemistry and in-situ hybridization, respectively. In contrast with the control groups, we observed enhanced expressions of IL-6, gp130, STAT3, and SHP2 protein and mRNA at the mesial and distal sides of the teeth with application of orthodontic forces in the experimental group. In contrast with the distal side, we observed enhanced expression of gp130 protein and mRNA at the mesial side in the experimental group. We observed enhanced expression of IL-6 and its key signaling factors gp130, STAT3, and SHP2 protein and mRNA at the tension and compression sides of the teeth with application of orthodontic forces. The mechanical loading applied for orthodontic tooth movement might induce changes in protein localization and mRNA expression patterns of IL-6 and its key signaling factors gp130, STAT3, and SHP2 at the tension and compression sides of the periodontal ligaments of the teeth in mouse models. The result might demonstrate the special role of IL-6 and its key signaling factors in the alveolar bone-modeling process.

Locally Inhibition of Orthodontic Relapse by Injection of Carbonated Hydroxy Apatite-Advanced Platelet Rich Fibrin in a Rabbit Model

Relapse is considered a significant failure after orthodontic treatment. In response to relapse, RANKL expressions will increase, while OPG expressions will decrease. CHA is thought to be one of an ideal candidate for enhancing bone formation. Moreover, a-PRF is a source high levels of growth factors that play a central role in the bone remodeling. This research was intended to investigate the effect of hydrogel CHA-aPRF in preventing relapse. Hydrogel-CHA was initially designed, with its degradation profile and FTIR (Fourie’s Transform Infrared) spectra were investigated as the basis to find out optimum formulation before incorporated with aPRF. Hydrogel-CHA microspheres were prepared in 3 different compositions: those were encoded 30-CHA, 40-CHA, and 50-CHA. After the hydrogel formulation and characterization were completed, 10 mL blood samples were collected, then centrifuged at 1500 rpm for 14 min. At the end of the centrifugation process, the aPRF clot was isolated and then pressed to obtain their releasate. The releasate aPRF was then loaded into the best formulation candidate of hydrogel CHA. The hydrogel incorporated aPRF was then gently injected on the mesial side of incisor gingival sulcus of the rabbit after orthodontic tooth movement. The FTIR analysis showed that carbonated apatite was successfully developed during the fabrication process of hydrogel-CHA microspheres. It was also known that degradation profile of 30-CHA was considered ideal compared to the other compositions. The application of CHA-aPRF (group C) was proven to significantly prevent relapse, indicated by lowest percentage of relapse 21 days after debonding (29.95±3.91%) compared to control group. Furthermore, it has been found that expressions of RANKL were significantly lowest (p<0.05) in group C on day 0, 3, and 7, while OPG expressions showed significantly highest (p<0.05) in group C on day 14 and 21 after debonding. These results indicate that incorporation of hydrogel-CHA has potential effect to enhance alveolar bone remodeling and prevent orthodontic relapse by stimulates OPG expression and suppresses RANKL expression.

Mean alveolar bone crest height decrement in subjects with an osteoporosis risk

People 40–75 years of age have an osteoporosis risk that may be signaled by a decrease in alveolar bone crest height. Thus, this measure can be used as an indicator of osteoporosis risk. This study was conducted to provide a database of decreased alveolar bone crest heights in ages at risk of osteoporosis by using intraoral radiographs. Forty periapical radiographs of the posterior region of tooth 36 (or 46) were measured twice at different times by two different observers. The interproximal decrease in alveolar bone crest height was measured from the alveolar bone crest to the cementoenamel junction (CEJ) for each tooth on the mesial and distal sides using a ruler (mm). The mean decrease in alveolar bone crest height in at-risk ages for osteoporosis was 3.50±1.085 mm, with a mean of 3.15±0.864 mm for those 45–59 years of age, and 3.90±1.156 mm for those aged 60–75 years. The mean decrease in alveolar bone crest height in people 60–75 years of age was larger than in people 45–59 years of age. There was a medium correlation between age and decreased alveolar bone crest height.

Peri‐implant bone density around implants of different lengths: A 3‐year follow‐up of a randomized clinical trial

Short dental implants are frequently placed, however, little is known about the effect of the loading force regarding an enhanced crown-to-implant ratio. The aim of this study was therefore to assess bone density changes after a 3-year period, on radiographs acquired from a randomized, controlled two-centre clinical study comparing implants of 6 and 10mm of length. Three predefined areas were chosen on standardized X-rays in order to assess grey-scale values of the peri-implant bone: One at the tip of the apex and two at half-length on the mesial and distal sides of the implant. Radiographs at all follow-up appointments had previously been calibrated using control fields in areas of constant density. Around short implants, peri-implant bone displayed significantly higher differences in grey-scale values (p=.031) after 3years, indicating a higher degree of mineralization. This phenomenon was not observed around long implants. A higher degree of mineralization around short implants was recorded. Whether this finding goes along with hampered bone adaptability, and accordingly, higher failure rates of short implants must be studied further in long-term clinical trials.

Clinical and radiographic outcomes of immediate and delayed placement of dental implants in molar and premolar regions.

The purpose of this retrospective study was to determine clinical and radiographic outcomes of immediate and delayed placement of dental implants in molar and premolar regions. Clinical and radiographic records of 116 patients who received implants in molar and premolar regions were included in this study. After implantation, patients were recalled for assessments at 1 month, 3 months, 6 months, 1 year, and every year thereafter. In addition, anatomic location, type of prosthesis, gender, stage, diameter, and length of implants were analyzed. Of these 116 patients, 55 were males, and 61 were females. Their mean age was 50.9 years. They received 85 immediate implants and 147 delayed implants in molar and premolar regions. Gender, type of prosthesis, stage, implant diameter, and implant length were not significantly different between the immediate placement group and the delayed placement group, although anatomic locations were significantly different between the 2 groups. Their mean follow up time after dental implantation was 3 years (range, 6 months to 9 years). Kaplan-Meier survival estimates showed 97.8% probability of survival up to 9 years in the delayed placement group and 100% probability of survival up to 8 years in the immediate placement group. There was no significant difference in implant survival according to the time of implantation. No significant difference in cervical bone loss (CBL) at the mesial or distal side was found between the 2 groups. CBL according to anatomic location, the type of prosthesis, or gender was not significantly different either between the 2 groups. However, CBL at distal side of 1-stage approach was significantly (P < .05) smaller in the delayed placement group than that in the immediate placement group. This study showed that immediate dental implantation in molar and premolar regions had good clinical and radiographic outcomes.

Autologous demineralised tooth matrix used as a biomaterial for alveolar ridge preservation

Background: Various bone substitutes are employed for ridge preservation. Tooth has been attracting attentions as a material for alveolar bone regeneration. Several studies showed that tooth possessed osteoconductive and osteoinductive properties similar to bone. Objective: To determine the efficacy of autologous demineralised tooth matrix (auto-DTM) in the preservation of alveolar ridge shape after tooth extraction. Methods: 40 symmetrical premolar extraction sockets using split-mouth design were randomly filled with auto-DTM and covered with platelet-rich fibrin (PRF) [DTM group] or PRF alone (control group). The evaluation of alveolar ridge dimensional changes, marginal bone resorption and bone healing density were performed in two-dimensional computer-based analysis and periapical radiographs (immediate, two weeks, four weeks, six weeks and eight weeks). Findings: Auto-DTM was well tolerated in all sites without incidences of postoperative complication. The dimensions of the ridges were significantly better preserved in DTM group than in control group. The radiographic resorption of marginal bone on the mesial side, distal side, as well as height of the sockets in the DTM group were not significantly different from those of the control group. Conclusions: Auto-DTM can be a useful alternative graft material for ridge preservation. Extraction socket grafted with auto-DTM and covered with PRF can reduce buccal bone collapse and facilitate bone-healing density as shown clinically and radiographically for short term ridge preservation.

Topographical relationship between positions of lingual foramina and attachment of mylohyoid muscle in mental region.

Lingual foramina can be observed between the lingual aspects of the mandible in humans. A sublingual artery is thought to exist in sublingual space and a submental artery in submaxillary space, which pierce the mandible through lingual foramina. During surgery for oral implant placement between apices of the mental foramen, it is important to determine the existence and positioning of lingual foramina. The purpose of this study was to investigate the positions of lingual foramina in relation to the mylohyoid muscle and vertical position of the mylohyoid line using cone-beam computed tomography (CBCT) images. We examined 20 formalin-perfused cadavers. The mylohyoid muscle was dissected and marked with a silicone tube, then CBCT images were obtained to evaluate the relationship of that muscle with lingual foramina. We observed 37 lingual foramina in the 20 cadavers. As for vertical positioning, 16 lingual foramina were found in sublingual space, while in horizontal positioning, 6 were found in the anterior region of sublingual space. The ratio of vertical distance from the inferior margin to the mylohyoid line and mental spine was lower in the anterior region as compared to the posterior region. In this study, lingual foramina were found to commonly exist in sublingual space above the mylohyoid muscle and pierce the mesial side. For evaluation of the vertical position of the mylohyoid line, it is better to use the stable mental spine rather than the alveolar process.

Retrospective Analysis of Biological and Technical Complications Using Individual CAD/CAM Abutments

Purpose: The aim of the present study was to assess the biological and technical complication and survival rates of implants and prosthetic superstructures using custom-milled CAD/CAM abutments made of titanium or zirconia. Material and Methods: A total of 109 patients were treated with 225 AstraTech OsseoSpeed implants (Dentsply IH) between July 2008 and November 2012 in the same private dental practice. Following submerged healing, the implants were uncovered and restored with Atlantis custom CAD/CAM abutments made of zirconia or titanium. Single crowns, fixed bridges, or telescope crowns as attachments for removable prostheses were connected to the abutments with zinc oxide phosphate cement. Patients were clinically and radiologically followed at the abutment level for a mean 20.85 months. The clinical assessment included biological and technical complications a well as the survival of the implants, abutments, and prosthetic superstructures. Mean crestal bone loss was assessed on standardized radiographs. Patient satisfaction was surveyed with a self-developed questionnaire. Results: The records of 69 patients (49 female, 20 male: mean age: 53.51 years) treated with 124 implants/custom abutments were included in the final analysis. Most abutments were made of titanium (n=90), followed by zirconia (n=34). The survival rates of implants and abutments were 100.00%. Eight restorations (6.50%) had to be replaced during follow-up, for an implant/abutment-related cumulative prosthetic success rate of 93.50%. The patient-related cumulative prosthetic survival rate was 92.75%. A mean bone gain of 0.06 mm (SD: 0.28 mm) on the mesial side and 0.11 mm (SD: 0.37 mm) at the distal side of the implants (n=122) was recorded. Only a few cases of soft-tissue complications such as mucositis, loss of papilla height, or bleeding on probing were observed. Therapy was rated as very good by 92.65% of patients. The esthetic result was assessed as very good as well by the majority of patients (88.41%). Due to the small sample size, no tests for statistical significance could be performed for any of the examination parameters, except for radiological crestal bone loss. No statistical significance was found for crestal bone loss as a function of the abutment material (p ≥ 0.05). Conclusions: Individual CAD/CAM -abutments are a good and predictable treatment option and deliver high patient satisfaction concerning the therapeutic and esthetic results.

Influence of Sinus Floor Configuration on Grafted Bone Remodeling After Osteotome Sinus Floor Elevation.

This study investigates influence of the sinus floor configuration on dimensional stability of grafted bone height after the osteotome sinus grafting procedure. Forty single-tooth dental implants inserted after placement of bioglass and/or allograft into the sinus area using an osteotome technique in 37 patients were evaluated in this retrospective study. Periapical radiographs were taken using the long-cone technique before and after implant placement. Specifically, radiographic measurements of grafted bone height at the mesial and distal side of each implant were taken, and the sinus floor configuration was classified into concave, angle, and flat according to the sinus floor profile at the implant site. Furthermore, the intruding angle, defined as the angle between the implant axis and sinus floor, was measured. All implants were clinically stable during a mean follow-up period of 39.2 months. Mean initial gain of sinus grafted bone height was 7.0 ± 1.9 mm, and later it was reduced to 4.6 ± 1.9 mm at follow-up (P <0.001). A greater reduction in grafted bone height was revealed in the flat sinus group compared with the concave group (P <0.001). Results from the linear regression showed larger intruding angles were statistically significantly associated with a greater reduction in grafted bone height (r2 = 0.55, P <0.001). All bioglass and/or allograft placed in the maxillary sinus after the osteotome technique underwent remodeling and shrinkage; however, the outcome of the procedure was more predictable in sinuses with a concave floor and small implant-intruding angles.

Alkaline phosphatase and lactate dehydrogenase enzyme activity in gingival crevicular fluid during orthodontic tooth movements

Background: Bone remodeling is a biologic process involving an acute inflammatory response in periodontal tissues during orthodontic tooth movement. The early response of periodontal tissues to mechanical stress involves metabolic changes that allow tooth movement. Aim of the Study: The aim of the present study was to evaluate the changes in alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) enzyme activity in gingival crevicular fluid (GCF) when forces are applied during initial alignment (Phase 1 [P1]) and retraction (Phase 2 [P2]). Settings and Design: The study was performed in a hospital-based population with an experimental design. Materials and Methods: A total of 17 patients (11–21 years) were included in the study, all requiring first premolar extractions undergoing fixed orthodontic treatment. Maxillary canine and mandibular second molar were used as test tooth (TT) and control tooth (CT) in each patient, respectively. On the 14th day after the start of each phase, 2 μL of GCF was collected from mesial side of both TT and CT for ALP and LDH activity determination using spectrophotometer. Statistical Analysis: Statistical analysis was performed with SPSS (version 13, SPSS Inc., Chicago, USA) package. The significance of differences in both phases at test or, at control site for LDH and ALP enzyme activity, was evaluated by performing Student's paired t-test. The significance of differences in between test and control sites in each phase separately was evaluated by performing Student's unpaired t-test. Results: There was a variation in enzyme activity during orthodontic tooth movement. At TT, there was statistically significant increase in ALP and LDH activity in P2 as compared to P1 with P = 0.005 and P Conclusion: This study concluded that ALP and LDH activity could be successfully estimated in the GCF, and ALP and LDH activity in GCF reflects the biologic activity in the periodontium during orthodontic tooth movements.

Transplantation of mature adipocyte-derived dedifferentiated fat cells into three-wall defects in the rat periodontium induces tissue regeneration.

The transplantation of dedifferentiated fat (DFAT) cells in combination with poly(d,l-lactic-co-glycolic acid) (PLGA) scaffolds has previously been proven as an effective approach in promoting periodontal tissue regeneration in a rat fenestration defect model. The aim of this study was to assess the regenerative potential of DFAT cells in a rat model of three-wall periodontal bone defect. Three-wall bone defects were created bilaterally on the mesial side of rat maxillary first molars and were either left untreated or treated by implantation of PLGA scaffolds with DFAT cells or PLGA alone. Four weeks after surgery, the tissues were processed for micro-computed tomography (micro-CT) and histomorphometric examination. Micro-CT revealed that the PLGA/DFAT group had significantly higher rates of bone regeneration than the other groups, while histomorphometric analysis showed that the PLGA/DFAT group had significantly higher densities of collagen fiber bundles in acellular and cellular cementum than the PLGA group. Moreover, the results indicate that the placement of the PLGA scaffold prevented the downgrowth of the junctional epithelium. These findings suggest that DFAT cells contribute to tissue regeneration in three-wall periodontal defects, while PLGA provides space necessary for periodontal tissue restoration.

Buccal Cortical Bone Thickness in Iraqi Arab Adults by Cone Beam Computed Tomography for Orthodontic Mini-Implants

Background: Cortical bone thickness is important for the stability of mini implants. Placing mini implants in sites of favorable cortical bone thickness would guarantee better initial stability and long-term success. The aim of this study was to investigate gender, side and jaw differences of the buccal cortical bone thickness as a guide for orthodontic mini screw placement. Materials and Methods: The sample was selected from the patients attending the Specialized Health Center in Al-Sadr City / 3D department. Thirty patients (15 males and 15 females) were selected and cone beam computerized tomographic images were done. Then the buccal cortical bone thickness was measured at thirteen inter radicular sites in the maxilla and mandible from the mesial side of the second molar to the mesial side of the second molar on the other side. The resulting data were statistically analyzed using independent t-test on SPSS program. Results: The buccal cortical bone thickness of the males was more than the females for both jaws. The mandibular buccal cortical bone thickness was thicker than in the maxillary and in the anterior region was thinner than in the posterior region for each jaw. The thickness of the buccal cortical bone was generally greater on the left side

Alkaline phosphatase and lactate dehydrogenase enzyme activity in gingival crevicular fluid during orthodontic tooth movement

Background: Bone remodeling is a biologic process involving an acute inflammatory response in periodontal tissues during orthodontic tooth movement. The early response of periodontal tissues to mechanical stress involves metabolic changes that allow tooth movement. Aim of the Study: The aim of the present study was to evaluate the changes in alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) enzyme activity in gingival crevicular fluid (GCF) when forces are applied during initial alignment (P1) and retraction (P2). Settings and Design: The study was performed in a hospital-based population with an experimental design. Materials and Methods: Seventeen participants (11–21 years) included in the study, all requiring first premolar extractions were undergoing fixed orthodontic treatment. Maxillary canine and mandibular second molar were used as test tooth (TT) and control tooth (CT) in each patient, respectively. On 14th day after the start of each phase, 2 μL of GCF was collected from mesial side of both TT and CT for ALP and LDH activity determination using a spectrophotometer. Statistical Analysis: The results were subjected for Student's t-test. Results: There was a variation in enzyme activity during orthodontic tooth movement. At TT, there was a statistically significant increase in ALP and LDH activity in P2 as compared to P1 with P = 0.005 and P ≤ 0.001, respectively. At CT, there was no statistically significant difference in ALP and LDH activity in P1 and P2 with P = 0.054 and P = 0.061, respectively. Conclusion: This study concluded that ALP and LDH activity could be successfully estimated in the GCF, and ALP and LDH activity in GCF reflects the biologic activity in the periodontium during orthodontic tooth movements.