Reconstruction of the extremely atrophied mandible with iliac crest onlay grafts followed by two endosteal implants: a retrospective study with long-term follow-up

Treatment outcomes of implant-retained lower dentures on two endosseous implants placed in severely atrophied mandibles after reconstruction with iliac crest onlay grafts were assessed in a retrospective observational study. All consecutive patients treated between 2000 and 2007 were recalled in 2012 (n = 40). Survival of the implants, the condition of hard and soft peri-implant tissues, and patient satisfaction were scored. One implant was lost after 5.5 years. The mean mandibular symphysis height was 8.9 ± 2.2, 16.4 ± 2.7, 15.7 ± 2.7, and 15.4 ± 2.5 mm at intake, after augmentation, after implantation, and at the last recall visit, respectively. Mean radiographic peri-implant bone loss was 0.6 ± 0.7 mm. Mean clinical index scores were very low. Patient satisfaction was high. Surgical complications related to the donor site were seroma (n = 1), haematoma (n = 2), and sensory disturbance of the lateral femoral cutaneous nerve (n = 1); all had resolved before placement of the implants. Eleven patients reported postsurgical sensory disturbances of the mental nerve, of whom five still experienced some sensory disturbance at the last recall visit. Augmentation of the extremely resorbed mandible with an iliac crest onlay graft followed by placement of two implants 4 months later provides a solid basis for a bar-retained overdenture with favourable clinical and radiographic results.     

Evaluation of the screw tent-pole technique for the repair of anterior maxilla width defects: a prospective,randomized, split-mouth study

The aim of this prospective study was to compare horizontal bone augmentation in the anterior maxilla associated with two types of tenting screw used in the screw tent-pole technique. Ten patients with a premaxilla width deficiency underwent grafting with protein-free xenograft bone. A split-mouth design was used, with sides allocated randomly to receive standard and wide-head tenting screws. Implants were installed after 9 months. Patients underwent clinical, cone beam computed tomography (CBCT), and histomorphometric evaluations. The buccal aspect of the ridge was classified as flat or concave in shape. Clinical measurements showed width augmentation of 1.05 mm, 2.45 mm, and 2.70 mm for standard screws and 1.50 mm, 3.10 mm, and 3.45 mm for wide-head screws, at the ridge, 5 mm, and 10 mm, respectively. CBCT showed width augmentation of 0.74 mm, 3.88 mm, and 4.72 mm for standard screws and 0.91 mm, 4.05 mm, and 4.37 mm for wide-head screws, at the crest, 5 mm, and 10 mm, respectively. Histomorphometric analysis showed 30.99% ± 26.43% vital bone tissue, 11.32% ± 9.68% graft residue, and 57.66% ± 21.85% connective tissue for standard screws and 32.64% ± 20.28%, 9.73% ± 5.82%, and 57.61% ± 20.15%, respectively, for wide-head screws. Flat alveolar ridges showed the lowest percentage of vital bone. New bone formation seems to be optimized on concave ridges. There was no statistically significant difference in bone gain results between standard and wide-head tenting screws.     

Effects of Choukroun’s platelet-rich fibrin on bone regeneration in combination with deproteinized bovine bone mineral in maxillary sinus augmentation: A histological and histomorphometric study

PurposeThe potential effect of Choukroun’s platelet-rich fibrin (PRF) in combination with allograft on promoting bone regeneration has been discussed in previous publications. This study aims to evaluate an influence of PRF on bone regeneration in sinus augmentation in combination with a xenograft, deproteinised bovine bone.Materials and methodsEleven sinuses from 10 patients with posterior maxillary bone atrophy were selected for the study. As a test group, six sinus floor elevations were grafted with a Bio-Oss and PRF mixture, and as control group, five sinuses were treated with Bio-Oss alone. Clinical and radiographic examinations were performed pre- and postoperatively. After 6 months of sinus augmentation, bone biopsies were obtained from the grafted posterior maxilla, and un-decalcified ground sections were prepared. Bone characteristics were evaluated using histological observation and histomorphometric analyses.ResultsNo adverse effect was observed in any case within the follow-up period of 6 months after sinus augmentation. Histological observation showed similar morphological characteristics for both the PRF and control groups. The percentage of new bone formation in the PRF group was about 1.4 times of that in control (18.35% ± 5.62% vs. 12.95% ± 5.33%), while the percentage of residual bone substitute in the control group was about 1.5 times higher as that in the PRF group (28.54% ± 12.01% vs. 19.16% ± 6.89%). The percentage of contact length between newly formed bone and bone substitute in the PRF group was 21.45% ± 14.57% vs. 18.57% ± 5.39% in the control. No significant statistical differences between the two groups were found in these observed parameters.ConclusionsOur preliminary result demonstrated neither an advantage nor disadvantage of the application of PRF in combination with deproteinised bovine bone mineral in sinus augmentation after a healing period of 6 months.     

Clinical effectiveness of autologous platelet rich fibrin in the management of infrabony periodontal defects

BackgroundThis interventional controlled clinical trial with split mouth design compares the clinical effectiveness of autologous platelet rich fibrin with open flap debridement in the management of infrabony periodontal defects.MethodsFifteen patients with paired contralateral infrabony defects were treated with open flap debridement and autologous platelet rich fibrin (experimental group) or open flap debridement alone (control group). The changes in probing pocket depth, clinical attachment level, and radiographic defect depth were evaluated. Patient perception regarding pain and discomfort following the procedures and early soft tissue healing responses were assessed by visual analog scales, scored 7 days after the surgical procedures. Final reevaluation was done 1 year after surgery.ResultsBaseline clinical and radiographic measurements were comparable between the groups. Reevaluation at 1 year revealed that both treatment modalities resulted in a significant decrease in probing pocket depth, gain in clinical attachment and radiographic bone fill of the defects compared to baseline. Postoperative differences observed between the two groups were 2.27±0.29 mm (P<0.001) for probing pocket depth, 3.33±0.35 mm (P<0.001) for clinical attachment level and 1.29±0.32 mm (P<0.001) for radiographic infrabony defect depth reduction, all in favor of the experimental group. Patient preference was greater and early healing response better for the experimental group as assessed by the visual analog scores.ConclusionWithin the limitations of this study it can be concluded that use of platelet rich fibrin is more effective than open flap debridement alone in the management of infrabony periodontal defects.     

Influence of low-level laser therapy on the healing process of autogenous bone block grafts in the jaws of systemically nicotine-modified rats: A histomorphometric study

ObjectiveTo analyze the influence of low-level laser therapy (LLLT) on the bone healing process of autogenous bone block grafts installed in nicotine systemically modified rats.MethodsSeventy-two rats (Wistar) were randomly assigned into 4 groups (n = 18). SS-BG: saline application + bone graft. SS-BG/LLLT: saline application + bone graft + LLLT. NIC-BG: nicotine application + bone graft. NIC-BG/LLLT: nicotine application + bone graft + LLLT. After 30 days of application of solutions, all animals received autogenous bone block graft in the jaw, with the donation from the parietal bone’s calvarial area. Treatment with LLLT was in bed-graft interface, after accommodation of the graft. The animals in each group were sacrificed at 7, 14, and 28 days after graft surgery.ResultsThe histologic analyses of NIC-BG group depicted a delay of osteogenic activity in the recipient bed-graft interface and the irradiation of tissue with LLLT provided better bone healing. The histometric analysis revealed that SS-BG/LLLT and NIC-BG/LLLT groups showed increased bone formation compared to BG-SS and NIC-BG groups, after 14 days (SS-BG 24.94% ± 13.06% versus SS-BG/LLLT 27.53% ± 19.07% and NIC-BG 14.27% ± 2.22% versus NIC-BG/LLLT 24.37% ± 11.93%) and 28 days (SS-BG 50.31% ± 2.69% versus SS-BG/LLLT 58 19% ± 12.32% and NIC-BG 36.89% ± 8.40% versus NIC-BG/LLLT 45.81% ± 6.03%).ConclusionNicotine harms bone formation in the bed-graft interface and LLLT action can mitigate this.     

Three-dimensional measurement of radiographic bone–implant contact lengths of zygomatic implants in zygomatic bone: a retrospective study of 66 implants in 28 patients

Zygomatic implant treatment is widely applied for severe maxillary atrophy to help rehabilitate the maxillary dentition. This retrospective study was performed to evaluate the actual radiographic bone–implant contact (rBIC) lengths of zygomatic implants. The records of 28 patients who underwent zygomatic implant surgery and subsequent follow-up examinations between August 2013 and September 2018 in the Department of Oral and Maxillofacial Surgery, Taipei Tzu Chi Hospital were reviewed. The surgeries were performed by a single surgeon using the same treatment protocol. All patients had a computed tomography scan at 1 year after the surgery. Using three-dimensional imaging software, an investigator measured the rBIC lengths of 66 implants and documented their clinical status. The implant survival rate was 100%. The mean rBIC length was significantly longer in male patients than in female patients (20.80 ± 5.88 mm versus 17.79 ± 6.34 mm; P = 0.028). The mean rBIC length of double zygomatic implants was significantly longer when compared to that of single implants (21.11 ± 6.23 mm versus 17.75 ± 5.85 mm; P = 0.027). This article is novel in reporting the exact rBIC lengths of zygomatic implants in a clinical setting. The results showed that zygomatic implants are a viable treatment modality for full-mouth rehabilitation.     

Bone regeneration with BMP-2 and hydroxyapatite in critical-size calvarial defects in rats

BackgroundThis study describes the effect of bone formation by BMP-2 (bone morphogenetic protein-2), a bone formation inducer, with or without hydroxyapatite (HAP) application to critical-size defects in rat calvarial bone.Material and methodsTwenty male Wistar rats were divided into four groups of 5 animals each: control, HAP, BMP, and mixed BMP/HAP. A Critical-size defect of 4 mm was made using a trephine in the calvarial bone and, after that, BMP and/or HAP was applied to the defect according to the grouping. Defects were evaluated radiographically and histologically using ImageJ color analyzer software at 4 weeks postoperatively.ResultsThe histological data were more precise than the radiologic data due to the white color of the porous-type HAP material. The highest radiopacity was noted in the mixed BMP/HAP group (162.07 ± 9.06), followed by the HAP group (133.15 ± 21.8), then the BMP group (100.79 ± 8.27), and, lastly, the control group (54.45 ± 8.39). After subtracting the white background and using ImageJ for histological analysis, the highest rate of osteochondrogenesis was in the mixed BMP/HAP group (85.29% ± 8.21), and then the BMP group (77.34% ± 7.39), followed by the HAP group (59.82% ± 11.23), and, lastly, the control group (40.27% ± 7.44). Differences in the values between groups were then analyzed using confidence intervals (CI) of 95 and 99%.ConclusionWithin 4 weeks, the mixed BMP/HAP group showed the highest level of bone induction, especially compared to the BMP group, but this was non-significant; even with a 95% CI, the result was negative. This reveals that BMP alone can be applied, with a final result the same as that seen in the mixed BMP/HAP group. BMP and HAP, both being osteoinducting agents, even though they differ from a material classification point of view, have a positive effect on osteogenesis.     

Bone regeneration at the distal aspect of the adjacent second molar after lower third molar coronectomy: a long-term analysis

A residual bone defect at the distal aspect of the adjacent second molar may occur after total removal of the lower third molar. Lower third molar coronectomy has been proved to be a safe alternative to total removal, but the extent of bone regeneration at the adjacent tooth after coronectomy is not well reported. The aim of this prospective study was to investigate the long-term bone regeneration at the distal aspect of the adjacent second molar after lower third molar coronectomy. Preoperative and postoperative cone beam computed tomography scans were measured to assess bone regeneration at the distobuccal (DB), mid-distal (MD), and distolingual (DL) aspects of the lower second molar. Forty-eight coronectomies in 37 patients (23 female) with a mean ± standard deviation age of 29.1 ± 7.2 years were assessed. The mean follow-up was 93.2 ± 8.7 months. The mean bone level increase at DB, MD, and DL aspects was 3.2 ± 1.6 mm, 3.5 ± 1.5 mm, and 3.2 ± 1.6 mm, respectively; the bone levels were significantly higher than the preoperative measurements (P < 0.001). Age and impaction patterns were not factors affecting bone regeneration. Based on this study, it appears that coronectomy of the lower third molar brings favourable bone regeneration at the distal aspect of the adjacent second molar.     

Development and evaluation of novel biodegradable chitosan based metformin intrapocket dental film for the management of periodontitis and alveolar bone loss in a rat model

ObjectiveThe aim of this study was to develop a chitosan-metformin based intrapocket dental film (CMIDF) for applications in the treatment of periodontitis and alveolar bone loss in an rat model of periodontitis.DesignCMIDF inserts were fabricated by the solvent casting technique. The fabricated inserts were evaluated for physical characteristics such as folding endurance, surface pH, mucoadhesive strength, metformin content uniformity, and release. X-ray diffraction analysis indicates no crystallinity of metformin in presence of chitosan which confirmed successful entrapment of metformin into the CMIDF. Fourier-transform infrared spectroscopy revealed stability of CMIDF and compatibility between metformin and chitosan. Periodontitis was induced by a combination of Porphyromonas gingivalis- lipopolysaccharide injections in combinations with ligatures around the mandibular first molar. We divided rats into 5 groups (8 rats/group): healthy, untreated periodontitis; periodontitis plus CMIDF-A (1.99 ± 0.09 mg metformin; total mass-4.01 ± 0.05 mg), periodontitis plus CMIDF-B (2.07 ± 0.06 mg metformin; total mass-7.56 ± 0.09 mg), and periodontitis plus chitosan film (7.61 ± 0.08 mg). After four weeks, mandibles were extracted to evaluate alveolar bone loss by micro-computerized tomography and histological techniques.ResultsAlveolar bone was intact in the healthy group. Local administration of CMIDF resulted in significant improvements in the alveolar bone properties when compared to the untreated periodontitis group. The study reported here demonstrates that novel CMIDF showed good antibacterial activity and effectively reduced alveolar bone destruction in a rat model of experimental periodontitis.ConclusionsNovel CMIDF showed good antibacterial activity and improved alveolar bone properties in a rat model.     

Volumetric CBCT analysis of the palatine process of the anterior maxilla: a potential source for bone grafts

The aim of this research was to use cone-beam computerized tomography (CBCT) to analyze the available bone volume in the palatine process of the maxilla (PPM), which is a potential source of bone grafts. 20 CBCT scans were evaluated. From the most caudal axial slice of the PPM, the bony surface was calculated cranially up to the nasal floor. The predetermined thickness of each slice was 0.9 mm. A 2 mm safety margin was established considering the incisive canal and teeth 14–24. A ±0.1 mm error deviation was established for all calculations. By connecting these points and those defined at the posterior bone boundary, a surface was obtained. A three-dimensional (3D) image of the delimited zone was constructed and analyzed using 3D imaging software. The study comprised 6 women and 14 men (mean age 39.4 ± 11.5 years). Calculated bone volume averaged 2.41 ± 0.785 cm³. The palatine process of the maxilla contains a considerable bone volume (2.41 ± 0.785 cm³). This area should be regarded as a potential donor site for the regeneration of maxillary atrophic bones. Further investigation is required before these findings lead to routine clinical application.     

Assessment of gingival biotype and facial hard/soft tissue dimensions in the maxillary anterior teeth region using cone beam computed tomography

ObjectiveThis study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT).DesignThis study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6 mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2 mm apical to the gingival margin was measured and GT <1.5 mm was categorized as thin while GT ≥1.5 mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane’s Q, chi-square and independent samples t-tests.ResultsThe BT around the maxillary central and lateral incisors and canine teeth at 4 and 6 mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P < 0.05). The mean GT at 2 and 4 mm apical to the CEJ was significantly different around central and lateral incisors (P < 0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P < 0.05).ConclusionThe two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.     

Comparison of procedures for immediate reconstruction of large osseous defects resulting from removal of a single tooth to prepare for insertion of an endosseous implant after healing

This study evaluated the treatment outcome of immediate reconstruction of 45 large osseous defects resulting from removal of a single tooth with a 1:2 mixture of Bio-Oss^® and autologous tuberosity bone, and three different procedures for soft tissue closing (Bio-Gide^® membrane, connective tissue graft, full-thickness palatal mucosa graft; n = 15 per group). All defects had an unfavourable osseous–gingival relationship and vertical bone loss of >5 mm. The hard and soft tissues were immediately reconstructed after removal of the tooth. Implants were inserted after 3 months. Patients’ acceptance, complications and postoperative morbidity were prospectively evaluated by standardized clinical and radiographic examinations up to 12 months after the augmentation procedure. The patients completed a questionnaire on subjective complaints related to the procedure. All hard–soft tissue procedures resulted in sufficient bone volume for the insertion of implants and a favourable aesthetic outcome. The gingival mid-buccal aesthetics before, and 1 year after, treatment significantly favoured the full-thickness palatal mucosa graft, showing a gain in gingival contour of 0.5 ± 0.8 mm; the other procedures resulted in a 1.2 ± 1.6 mm decrease. Of the procedures evaluated, a full-thickness palatal mucosa graft was the most predictable for immediate reconstruction of the socket after tooth removal.     

Pedicle length in the inferiorly based buccinator myomucosal island flap: a cadaveric study

The inferiorly based buccinator myomucosal island flap is a useful reconstructive option for medium-sized intraoral mucosal defects. The pedicle length of this flap has not yet been determined. Thirteen fresh cadavers (26 sides) with intact faces were studied. An inferiorly based buccinator myomucosal island flap was elevated. Various measurements were taken, including pedicle length, paddle area, and pedicle length after dissection of the facial artery through the submandibular salivary gland; the presence of the facial artery or vein in the pedicle and the number of perforators were also evaluated. The mean pedicle lengths in the right and left sides were 4.8 ± 0.6 cm and 4.9 ± 0.6 cm, respectively. The mean pedicle lengths after dissection of the facial artery through the submandibular salivary gland were 7.8 ± 0.7 cm (right side) and 7.7 ± 0.6 cm (left side). The pedicle contained only the facial artery in six sides. There were two to three perforator branches from the facial artery to the mucosal paddle. Paddle sizes of the flap were in the range of 2.2 × 2.1 cm to 3.5 × 3 cm. This flap is suitable for the reconstruction of the floor of the mouth and tongue. Pedicle length can be increased significantly by dissecting the facial artery through the submandibular salivary gland.     

Maxillary sinus floor augmentation and dental implant placement using dentin matrix protein-1 gene-modified bone marrow stromal cells mixed with deproteinized boving bone: A comparative study in beagles

ObjectiveThe aim of the study was to evaluate the effects of the combined use of dentin matrix protein-1 (DMP1) gene-modified bone marrow stromal cells (BMSCs) and Bio-Oss^® for maxillary sinus floor augmentation (MSFA) implant placement in dogs.Materials and methodsBMSCs were derived from bone marrow of six beagles and cultured. The cells were transduced with a lentiviral vector overexpressing the DMP1 gene and enhanced green fluorescent protein (EGFP) gene (Lenti-DMP1/EGFP) in test group, and with a lentiviral vector encoding EGFP gene (Lenti-EGFP) in control group. Six dogs received sinus augmentations using the bilateral approach with a simultaneous implant placement at each site respectively. At the same concentration, 2 × 10⁷ cells/ml, one sinus was grafted using a mixture of autologous DMP1/EGFP gene-modified BMSCs and Bio-Oss^® (DMP1 group), and the contralateral sinus was grafted with autologous EGFP gene-modified bMSCs and Bio-Oss^® (EGFP group). After a 3 month healing period, bone regeneration and osseointegration were evaluated using histologic and histomorphometric methods.ResultsThe bone-implant contact (BIC) and the bone area fraction in the DMP1 group (BIC: 34.67% ± 8.23%, bone area fraction: 35.16% ± 3.32%) were significantly greater compared with the EGFP group (BIC: 26.06% ± 5.16%, bone area fraction: 20.74% ± 1.63%) (P < 0.05). No significant difference between the residual bone substitute material volume (BSMV) in the DMP1 group (35.86 ± 7.35) and the EGFP group (32.16 ± 9.16) was found in our study (P > 0.05).ConclusionBMSCs modified with the DMP1 gene can be used as an adjunct to Bio-Oss^® to enhance new bone formation and the osseointegration of dental implants in MSFA of dogs.     

A novel vibratory stimulation-based splint for chronic and untreatable masticatory myofascial pain: A case-series

AimThis clinical report aimed to introduce a novel vibratory stimulation-based occlusal splint (VibS) for management of chronic and untreatable masticatory myofascial pain (MMFP).MethodsThis study was conducted on four chronic MMFP patients (mean age: 27.5 ± 5.56 years, females) who were diagnosed according to the research diagnostic criteria for temporomandibular disorders (RDC/TMD), and who were using stabilization splints for more than 6 months and still complained of pain above 40 mm in a 100-mm VAS scale. The included subjects utilized the active VibS and subsequently the inactive VibS during 30 days in each trial, separated by a wash-out period of at least 8 months. VAS pain levels were the only measured dependent variable, and were recorded before and after the use of active VibS and inactive VibS.ResultsAt baseline, mean VAS pain levels before using the active or inactive splint were 54.5 ± 19.8 mm and 44.0 ± 13.6 mm, respectively. After using the active VibS, mean pain level decreased by 77% (VASpos-pre = ?42.0 ± 30.3 mm). On the other hand, after using the inactive VibS, severe pain aggravation of 67% in magnitude was observed (VASpos-pre = +29.5 ± 21.5 mm).ConclusionThis case-series study demonstrated a good tendency of this novel VibS in chronic MMFP alleviation after a 4-week management period compared to a control inactive VibS.     

Proportion of deproteinized bovine bone and autogenous bone affects bone formation in the treatment of calvarial defects in rabbits

This study assessed new bone formation generated using three different proportions of autogenous bone (AB) and deproteinized bovine bone (DBB). Thirty bicortical skull defects were prepared in 15 rabbits, divided into 3 groups: Group 1, critical size defect (CSD) versus AB as controls; Group 2, DBB versus a composite of AB and DBB using a proportion of 1:1; and Group 3, a composite of AB and DBB using a proportion of 1:2 versus a proportion of 1:4. After 8 weeks, radiographic evaluation was assessed using densitometry and new bone formation by histomorphometry. The mean optical density of the CSD (0.108 ± 0.238) and AB (0.352 ± 0.161) groups differed significantly from the DBB group (1.044 ± 0.093) and the groups using a proportion of 1:1 (0.905 ± 0.078), 1:2 (0.865 ± 0.294) and 1:4 (0.867 ± 0.304). Histomorphometry revealed a higher percentage of new bone in the AB group (30.223 ± 16.722) than in the groups using proportions of 1:2 (22.639 ± 5.659), 1:1 (20.929 ± 6.169), 1:4 (9.621 ± 2.400), DBB (14.441 ± 2.742) and CSD (10.645 ± 8.868), respectively. The 1:2 group had significantly higher bone content than the 1:4 group. The proportions of 1:1 and 1:2 resulted in greater bone formation than the proportion of 1:4, DBB and CSD.     

A three-dimensional finite element analysis of the stress distribution on morse taper implants surface

PurposeThis finite element analysis (FEA) compared stress distribution on external surface of different morse taper implants, varying implant bodies length and dimensions of metal-ceramic crowns in order to maintain the occlusal alignment.MethodsThree-dimensional finite element (FE) models were designed representing a posterior left side segment of the mandible: group 0, 3 implants of 11 mm length; group 1, implants of 13 mm, 11 mm and 5 mm length; group 2, 1 implant of 11 mm and 2 implants of 5 mm length; group 3, 3 implants of 5 mm length. The abutments heights were 3.5 mm for 13 mm and 11 mm implants (regular) and 0.8 mm for 5 mm implants (short). Evaluation was performed on a computer program (Ansys software), with oblique loads of 365 N for molars and 200 N for premolars, applied on ridges of cusps and grooves.ResultsAbutments with 0.8 mm height generated less von Mises stresses compared with 3.5 mm height. The use of short implants associated with bigger crowns concentrated higher stress distribution and stress values on the surface implants, principally on the vestibular side (oblique direction of the loads). The more distal implant concentrated higher stress.ConclusionsMoreover, these 5 mm implants were positioned at the cortical bone level, which has higher elastic modulus and may have influenced at the stress distribution. However, despite the higher stresses, these implants were well able to withstand the applied forces.     

Deleterious effect of chronic continuous hypoxia on oral health

ObjectiveTo evaluate the effect of chronic continuous hypoxia (CCH) in alveolar bone and its correlation with the inflammatory markers which play a key role in the development of periodontitis.Material and methodsWistar rats were exposed to CCH (600 mbar, 3 months). Macroscopic and histological analyses of alveolar bone were performed, together with measurement of oxidative stress and inflammatory parameters in gums and submandibular glands (SMG).ResultsHCC induced cortical alveolar bone loss, decreased interradicular bone volume and increased the periodontal ligament height compared to control rats (p < 0.05). CCH enhanced iNOS activity in gums (from 2735,04 ± 662,96 nmol/min/mg proteins to 4289,58 ± 915,63 p < 0.05) and in SMG (from 56,71 ± 12,05 nmol/min/mg proteins to 90,15 ± 21,78 p < 0.05). PGE₂ did not change in gums or in SMG by means of CCH, while TNFα decreased in gums (p < 0.05). Regarding oxidative stress, thiobarbituric acid reactive species concentration in CCH animals was higher both in gums as in SMG, and catalase activity was decreased in SMG.ConclusionHigher iNOS activity both in gums and SMG under CCH could be associated with the alveolar bone loss observed. The increase in oxidative stress occurring in SMG and gums, together with a lower antioxidant capacity might indicate a deleterious effect of HX in oral health.     

One-step lateral window approach for removal of benign minor sinus pathologies combined with transcrestal sinus floor elevation without bone grafts: a retrospective study

The aim of this study was to evaluate the clinical and radiographic outcomes of a lateral window approach for removal of benign minor sinus pathologies combined with transcrestal sinus floor elevation. From 2014 to 2018, all patients who received sinus pathology removal via a lateral window approach combined with transcrestal sinus floor elevation were screened. The serous exudate or minor sinus pathology was drained or removed via lateral window approach. Subsequently, transcrestal sinus floor elevation without grafting and simultaneous implant placement were performed. Panoramic radiographs and cone-beam computed tomography were taken preoperatively, immediately after surgery, and after prosthesis delivery. Twelve patients were included in this study. The decrease in Schneiderian membrane thickness was statistically significant (P < 0.001). Endo-sinus bone formation was observed on the buccal (1.35 ± 2.31 mm) and palatal (1.61 ± 2.65 mm) sites of the implant. The implant survival rate was 100%. All implants survived for an average of 21.83 ± 11.11 months. Within the limitations of this study, we suggest that the lateral window approach for minor sinus pathology removal combined with transcrestal sinus floor elevation has several advantages including endo-sinus bone gain without bone graft, minimal patient discomfort, reduced postoperative complications and shorter treatment period.