جستجوی مقالات مرتبط با کلیدواژه "alveolar bone loss" در نشریات گروه "پزشکی"

Rehabilitating thin jaws without reconstructive surgery entails using narrow implants. The proposed treatment adopted an innovative implant system, allowing the mini-screws to be parallel and immediately loaded. A mandible, wearing an overdenture, was functionalized contextually to the residual dental extraction and the placement of six 2.4-mm thick one-piece implants. Low-profile intermediate abutments, the LEMs, able to rotate over the spherical heads of the fixtures, were connected after suturing, oriented, and blocked in a mutual parallel position. The copings, engaging with a tapered juncture of the LEMs, resulted in their alignment to be intraorally wedged together. The provisional superstructure enclosed the copings and was immediately connected to the implants, and the definitive prosthesis was delivered after three months. No clinical signs of peri-implantitis or radiographically evident bone loss were recorded after a two-year follow-up without any prosthetic complication. No cases have been published regarding mini-implants bearing fixed prosthesis rehabilitation.

Keratinized mucosa width (KMW) has an essential role in peri-implant health. This study aimed to evaluate the impact of KMW on marginal bone loss (MBL) around overdenture-supported dental implants.

In this cohort study, completely edentulous patients received an overdenture with implants in the maxilla and mandible. Two implants were placed in the maxilla and mandible. Ball attachments were used. KMW was measured, and gingival biotype was determined. MBL was evaluated on digital parallel radiographs taken at 12 and 24 months after loading. KMW was the predictive factor, and MBL was the outcome of the study. Data were analyzed using SPSS 21 via Pearson’s correlation test, independent t-test, and Chi-square test (alpha=0.05). 

Eighty implants in 20 patients were studied. The mean KMW was 2.05±0.88 mm. The mean MBL was 1.32±0.46 mm at 12 months after loading, and 1.71±0.49 mm at 24 months after loading. Analysis of the data demonstrated a correlation between MBL at 12 and 24 months after loading with KMW and dental implant diameter (P<0.001).

It appears that narrow KMW may be associated with an increase in MBL in two-implant-supported overdentures. Gingival biotype may play a role in the detrimental effect of narrow keratinized mucosa on MBL.

Alveolar bone resorption may complicate dental implantation of the edentulous area. The quantity of residual bone depends on the region, and it is uncertain which region may present more difficulties before implantation. In this study, the alveolar bones of patients who had cone beam computed tomography (CBCT) before dental implantation were examined, and residual bone was evaluated based on age, gender, and the location of the missing tooth.  

In this observational study, the patients with CBCT were divided into two age groups: 18 to 35 and 36 and older. Also,  the edentulous regions were divided into incisor, premolar, and molar regions. Radiographic measurements were performed with a cross-sectional aspect in the single-tooth deficiency regions of the patients; bone height and width measurements were made.  

This study included 164 CBCT scans from individuals (99 females and 65 males). There was no statistically significant difference between the bone heights and between bone widths at the 1st, 3rd, 5th, and 7th mm according to age or gender  (P>0.05). Bone height in the incisor tooth region (ITR) and bone width at the 1st, 3rd, 5th, and 7th mm in the molar tooth region  (MTR) were significantly larger (P<0.01).  

This study revealed that the bone width at the 1st mm of the ITR was insufficient for dental implant placement and that horizontal bone augmentation was needed.

The present study aimed to assess the prevalence of periodontal bony lesions in radiographs in the Iranian population.

In this analytical cross-sectional study, 440 radiographic images of patients aged 15-60 years were selected based on the study’s inclusion criteria. Two researchers evaluated all radiographs and recorded patient age, gender, and bone-related lesions (horizontal , vertical and furca involvement) in a checklist. Chi-square test was used for data analysis. (α=0.05).

273 images (62.05%) had no lesions and 167 images (37.95%) had lesions. In the 167 examined images, a total of 845 bone lesions were observed . The highest frequency was in horizontal lesions in the anterior mandible and central incisor teeth and the lowest type of lesion was related to vertical lesions in the posterior mandible and in the third molar (P<0.001). The most types of bone lesions; Based on the type of tooth, was related to horizontal lesions in the lateral incisor and the lowest type of lesion was related to vertical lesions in the first premolar tooth (P<0.001). Based on restoration, the most related to horizontal lesions in amalgam and the least related to vertical lesions and furca in veneer (P<0.001). Based on the contact status, the most was related to horizontal lesions in open contact and the least was related to vertical lesions (P<0.001).

Based on this study, there is a significant association between the type of periodontal bony lesion and involved teeth, restoration type, contact status, presence of calculus on radiographs.

The present study aims to evaluate the efficacy of administered diosgenin (DG) which has anti-oxidant and anti-inflammatory effects, on alveolar bone loss (ABL) and apoptosis in diabetic rats with periodontitis.  Forty male Wistar albino rats (n=40) were divided into five subgroups; control (non-ligated), periodontitis (P), diabetes mellitus (DM), P+DM, and P+DM+DG. To stimulate experimental periodontitis, a ligature was embedded at the gingival margin of the lower first molars for each rat, and diabetes was induced by streptozotocin (STZ) for DM groups. Then, DG (96 mg/kg daily) was performed on the P+DM+DG group by oral gavage for 29 days. At day 30, all animals were euthanized and the distance from the cement-enamel junction to the alveolar bone margin was measured using cone-beam computed tomography as ABL. In addition, immunohistochemical analyses were used to evaluate the expression levels of alkaline phosphatase (ALP), osteocalcin (OCN), bone morphogenetic protein 2 (BMP-2), receptor activator of NF-κB ligand (RANKL), collagen type I (Col-1), B-cell lymphoma-2 (Bcl-2), and Bcl-2-associated X protein (Bax).  Induction of periodontitis and diabetes significantly increased ABL (P<0.05). DG administration significantly reduced ABL, expression of RANKL and Bax, and enhanced the expression of ALP, OCN, BMP-2, Bcl-2, and Col-1 in the P+DM+DG group compared with the P+DM group (P<0.05).  It is revealed that DG considerably enhanced bone formation and contributed to periodontal healing in this experimental study performed in diabetic rats.

Periodontal clinical parameters are highly sensitive for the assessment of bone resorption, while radiographic images are highly specific. Two-dimensional parallel periapical (PA) and bitewing (BW) intraoral radiographs are used as adjuvant methods to assess bone resorption in periodontal diseases. The present study aimed to compare the efficacy of PA and BW radiographs in assessing marginal bone level.

This cross-sectional study was conducted on 77 (52 females and 25 males) subjects with a mean age of 40.12±14.9 years with chronic periodontitis. Parallel PA and BW radiographs of patients, who required periodontal flap surgery or crown lengthening, were acquired, and evaluated. The distance between the alveolar bone crest (ABC) and the cemento-enamel junction (CEJ) was determined during surgery using the Williams probe. The same distance was measured in proximal areas on intraoral radiographs using Romexis Version 11.4. To evaluate intra-observer agreement, three observers re-evaluated the radiographs after a minimum of 1 week. Intra-class correlation coefficient (ICC) was applied to evaluate the inter- and intra-observer agreement. Data were analyzed using the Shapiro-Wilk test and paired t-test.

According to the results, the mean distance between the CEJ and ABC was 4.61±1.22 mm, and the mean distance on the PA and BW radiographs was 4.20±1.23 (P<0.001) and 4.02±1.06 mm (P<0.001), respectively. PA radiography was more accurate than BW radiography, although the difference was insignificant (P=0.182). The mean ICC value of the inter-observer agreement was 0.88 for BW and 0.87 for PA radiographs. The mean intra-observer agreement was 0.97 and 0.95 for BW and PA radiographs, respectively.

The accuracy of PA radiography was higher than BW radiography. However, there was no significant difference regarding the accuracy of these two techniques in determining the level of ABC in the posterior area of the jaws.

Statement of the Problem: 

For many years, practitioners have been encountered with dental rehabilitation of atrophic jaws. Among many of alternatives, free iliac graft can be a reasonable and also problematic choice to be accomplished.   

The aim of this study was to evaluate the implant survival rate and bone loss in implants inserted in reconstructed jaws with free iliac graft.

In this clinical trial study, twelve patients that underwent bone reconstruction with free iliac graft were included in this retrospective study. The patients underwent surgery over a 6-year period from September 2011 to July 2017. Panoramic images were taken immediately after implant insertion and at the follow-up session. The parameters that were assessed included implant survival rate, bone level changes, and surrounding tissue conditions.

One hundred and nine implants were placed in eight female and four male patients, of which 65 (59.6%) were inserted in the reconstructed maxilla and 44 (40.3%) in the reconstructed mandible. The interval between the reconstruction surgery and follow-up session was 28.75 months and the mean interval between implant insertion and the follow-up session was 21.75 months, ranging from 6 to 72 months. The total average of crestal bone resorption was 2.44 mm (range: 0 to 5.43 mm).

This study found that rehabilitation of atrophic jaws with dental implants placed in free iliac graft was associated with acceptable marginal bone loss, survival rate, satisfaction, and esthetic results among the patients.

Statement of the Problem:

 Marginal bone loss (MBL) is an important factor in dental implant failure. The number of implants may affect MBL.

The aim of this study was to compare MBL in patients who received two or three implants for replacement of three missing teeth in the posterior mandible.

This prospective cohort study evaluated patients who required replacement of three missing teeth in the posterior mandible with dental implants. The patients were assigned to two groups. In the group 1, the edentulous area was restored with two implants and a pontic while three implants were placed for this purpose in the group 2. The MBL was compared between the two groups at 12 and 24 months after loading.

Forty-two implants were studied in group 1 and 36 implants in the group 2. The mean MBL was 0.90±0.12mm in the group 1 and 0.89±0.12mm in the group 2 at 12 months after loading. The mean MBL was 1.00±0.10mm in the group 1 and 0.98±0.10mm in the group 2 at 24 months after implant loading. The mean of MBL was not statistically different between the two groups at 12 months and 24 months (p> 0.05).

It seems that the use of two or three implants for replacement of three missing teeth in the posterior mandible is not associated with an increase in MBL.

This study aimed to assess the relationship between the osteoporotic condition and periodontitis in postmenopausal women.

Ninety‑four women aged 50–80 years were studied in this cross‑sectional study. Bone mineral density (BMD) of lumbar vertebra BMD (LBMD), total hip BMD (HBMD), and neck of femur BMD (NBMD) was assessed using standardized dual‑energy X‑ray absorptiometry (DXA) (normal: T‑score ≥−1, osteopenic: −2.5 ≤ t‑score <−1, osteoporotic: T‑score <−2.5). Bleeding point index (BI), O’Leary plaque index (PI), and clinical attachment loss (CAL) were recorded. Cementoenamel junction, alveolar‑crest distance (CEJ‑AC) was measured from cone‑beam computed tomography images. Periodontitis severity was represented by CAL and CEJ‑AC distance. One‑way analysis of variance followed by Post hoc Tukey was performed for examining differences among the groups for different variables. Pearson correlation coefficient® and backward regression analysis were used to investigate the effect of confounding variables on CEJ‑AC as the dependent variable. Significance was considered at P < 0.05.

Mean CEJ‑AC was significantly higher in the osteoporotic and osteopenic groups compared to the normal group (P = 0.001). There was a significant positive correlation between CEJ‑AC and NBMD and LBMD (P < 0.001). The associations between LBMD and CEJ‑AC existed even after adjusting for confounding factors (P = 0.002). The differences in BI, PI, and CAL were not statistically different between the groups (P > 0.05).

Although osteoporosis is not the main cause of periodontitis, it can indirectly affect periodontal status by increasing CEJ‑AC. Early diagnosis of osteoporosis followed by early referral to a dentist for the treatment of potential existing periodontal diseases is important to avoid complications among postmenopausal women

The first purpose of treatment of periodontal disease and bone loss is to regenerate the lost structures and preserve the sound residual tissues. Different techniques and materials are utilized for alveolar bone loss treatment. This review summarizes the techniques and materials utilized for treatment of alveolar bone loss due to periodontitis.

A search was performed in PubMed, Cochrane Library, and Google Scholar databases from 1990 to 2021. Totally, 133 studies were collected and reviewed, and finally, 31 studies were selected for the analysis.

Of 31 papers, 13 were about intra-bony defects, and others were about furcation involvement defects. Each article suggested different techniques and materials. Clinical parameters such as plaque index, gingival index, probing pocket depth (PPD), clinical attachment loss (CAL), and gingival margin position had been measured in studies, and a few techniques showed better results than others. Treatment of furcation defects is difficult in periodontal therapy. We should note that surgical procedures do not have any superiority over non-surgical procedures.

In conclusion, to decide about the best technique, site of defect, severity of disease, the available materials, and the clinician’s knowledge should be considered.

This study aimed to investigate the function of transient receptor potential vanilloid 1 (TRPV1) in regulating periodontal lesions. In addition, we explored the underlying mechanism of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway.

Lipopolysaccharide (LPS) stimulation of human periodontal ligament cells (HPDLCs) was used to construct a periodontitis cell model, and experimental periodontitis (EP) rats were established by ligation. The mechanism by which TRPV1 regulates periodontitis was further verified by injecting the TRPV1 agonist capsaicin (CPS) and antagonist capsazepine (CPZ) into the gingiva of rats; the alveolar bone losses in each group were measured by stereomicroscopy. Real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting (WB) were used to research the expression of TRPV1 and proinflammatory cytokines, and WB was performed to test the phosphorylation of PI3K and AKT.

In vitro experiments showed that LPS induced the upregulation of TRPV1 and proinflammatory cytokines and promoted the phosphorylation of PI3K and AKT proteins in HPDLCs, which was consistent with their expression in the rat periodontitis model. Moreover, in vivo studies indicated that CPZ had anti-inflammatory effects through the PI3K/AKT pathway and inhibited bone loss induced by periodontal ligation in rats, while CPS had the opposite effect.

TRPV1 was involved in the process of alveolar bone defects and the inflammatory response in rats with periodontitis induced by ligation. Its mechanism might be related to the phosphorylation of related proteins in the PI3K/AKT signaling pathway.

To assess the influence of gender and age on different parameters of alveolar bone loss using specific radiomorphometric indices on panoramic radiographs to aid in identifying patients with possible low bone mineral density (BMD).

The present cross‑sectional study included 80 subjects in whom mandibular cortical index (MCI), mandibular cortical width (MCW), panoramic mandibular index (PMI), alveolar bone loss (ABL), and bone height in 1st premolar (Hp) and 1st molar (Hm) were assessed to evaluate the alveolar bone loss.

The findings of the present study revealed a significant association between MCI and age for females with C2 and C3 categories being more common with advancing age. Also, a significant difference could be seen in relation to gender (p‑value = 0.0315) for MCW with a concomitant decrease in values of MCW in females >60 years of age. The vertical bone height of the edentulous mandible at 1st premolar (Hp) (p‑value = 0.0071) and 1st molar (Hm) (p‑value = 0.0044) regions were also found to be more in males than females.

Panoramic radiographic measurements provided valuable information for alveolar bone loss in terms of gender and age based on specific radiomorphometric parameters.

Implant-supported overdentures are a treatment option for edentulous patients. One of the important factors in determining the prognosis of overdenture treatment is to control the distribution of stress in the implant-bone and attachment complex. This study assessed the effect of implant abutment height difference on stress distribution in mandibular overdentures.

In this study, three models of mandibular overdentures were designed independently using finite element analysis (FEA). The implants were placed at different height levels relative to the adjacent implant (1 mm, 2 mm and 3 mm). A 100 N load was applied to the overdenture, and the software was programmed for stress analysis in the models. The load was applied bilaterally, unilaterally, vertically, and obliquely. Finally, the von Misses stresses were produced numerically, color-coded, and compared among the models.

The models in which the implants had up to 2 mm height difference with each other showed better stress distribution than the model with 3 mm height difference between the implants. In all conditions, the implant neck showed the high-est concentration of stress among all areas of the implant. Lower stress levels were found in the cancellous bone than the cortical bone in different loading conditions.

Lower Von Mises stress values were found in the models with up to 2 mm difference in implant height, and higher stress values were noted in the cortical bone and the implant neck compared with trabecular bone.

Intrabony defects are among the most important signs of progression of periodontal disease. Complete tissue regeneration is the ideal goal of periodontal treatment, and regenerative methods aim to achieve this goal. New studies have reported the positive efficacy of chitosan to enhance the recovery of bony defects. This study aimed to clinically and radiographically assess the efficacy of chitosan particles for treatment of intrabony periodontal defects.

In this clinical trial, 18 intrabony three-wall periodontal defects were randomly divided into three groups (n=6). The control group only received conventional flap surgery with a sulcular incision. In the second group, low molecular weight (100,000-300,000g/mol) chitosan was used in the three-wall intrabony defects during surgery while high molecular weight chitosan particles (600,000-800,000 g/mol) were used in the third group. The probing pocket depth (PPD), clinical attachment level (CAL) and radiographic defect depth (RDD) were measured at baseline and at 6 and 12 months later. Repeated measures ANOVA, and McNemar’s test were used for statistical analysis.

In both the control (P<0.001) and coarse chitosan (P=0.035) groups, a significant difference was noted in PPD before and after surgery. CAL was not significantly different among the three groups (P>0.05). No significant difference was noted on radiographs between the groups regarding the regenerated bone density.

Chitosan showed no positive efficacy for treatment of three-wall periodontal bone defects.

Bacteria colonization is the main cause of periodontal diseases and may be effected by ABO blood types. Since implant survival is severely reduced by peri-implant disease, this study aimed to evaluate the marginal bone resorption levels and survival rates of implants which were followed for 1-8 years and analyze these values with respect to demographic data and blood types. Patients who had undergone implant treatment and had prosthetic rehabilitation at the School of Dentistry in Van Yuzuncu Yil University, Van, Turkey, between March 2010 and March 2017 were studied in this cross-sectional retrospective study. In this study, 272 individuals were included, and a total of 963 implants were evaluated. Individuals who had implant treatment were called for control visits and clinical and radiological examinations. The effects of blood types were evaluated in terms of implant survival, failing implant, post-operative complications, and mesial-distal marginal bone resorption. Statistical analysis was performed using NCSS 2007 software. The Kruskal-Wallis test, Pearson's chi-square test, Fisher's exact test, and Fisher-Freeman-Halton exact test were used for statistical analysis. Statistical significance level was considered at P < 0.05. The mean age of the participants was 49.49 ± 11.92 years. The blood types of the participants were O (52.2%), A (30.5%), B (11.1%), and AB (6.3%). The implant survival rate was found to be 98.3%. There was no significant difference between blood types in terms of gender and age (P > 0.05). On the other hand, mesial-distal bone resorption was higher in patients with O blood type older than 50 years (P < 0.05). The fact that 52.2% of the patients with implants had O blood type, which is higher than the Turkish general population, may suggest that individuals with O blood type are more prone to tooth loss. To the best of our knowledge, this is the first study that assessed the impact of blood type on the success of dental implants.

The potent anti-inflammatory and immunosuppressive properties of glucocorticoids (GCs) might influence the progression of some disorders, such as periodontitis. Hence, this study aimed to investigate the influence of dexamethasone (DEX) on the alveolar bone loss (ABL) of healthy and periodontally compromised molars in rats.

Thirty male rats were randomly assigned to two groups: physiological saline solution (PSS) and DEX. The animals received subcutaneous injections of either 0.5 mL of PSS) (group PSS) or 2 mg/kg of DEX (group DEX) from one day before experimental periodontitis (EP) induction until euthanasia. EP was induced through ligature placement around the mandibular lower first molars at day 0. Contralateral molars remained unligated. Ten animals per period were euthanized on days 3, 7, and 14. Morphometric analysis was performed to access the ABL. Data were statistically analyzed with ANOVA followed by post hoc Tukey tests (P≤0.05).

Higher ABL was observed in both groups on days 7 and 14 than on day 3 (P≤0.05). Concerning periodontitis, higher ABL was observed in group DEX on days 3, 7, and 14 days than group PSS at the same time intervals (P≤0.05). Also, even in the contralateral unligated molars, group DEX exhibited higher ABL on days 3, 7, and 14 days than group PSS at the same time intervals (P≤0.05).

Collectively, it can be concluded that DEX aggravates EP and induces spontaneous ABL in the healthy periodontium.

Patients with tooth loss in the posterior mandible,requiring dental implantation, mayalso require other simultaneous surgical procedures due to severe atrophy, such as nerve lateralization. However, it is difficult to achieve the appropriate width and height in this area in patients with atrophic ridges. In the present case, we performed inferior alveolar nerve (IAN) repositioning and iliac bone grafting simultaneously to achieve satisfactory width and height in an edentulous adult patient with insufficient bone height and width in the posterior mandible. The follow-up did not indicateany nerve damage, anda significant increase was observed in the bone height, which facilitated successful implantation. This study showed the feasibility of IAN repositioning withsimultaneous iliac bone autogenous grafting for thetreatment of atrophic posterior mandibular ridges. However, further studies are required to confirm the safety and efficacy of this combinational method. Keywords: Alveolar bone loss; Mandibular nerve; Nerve repositioning; Iliac bone; Autografts.