Loss Of Dentition Research Articles

PHYSIOLOGICAL AND SOCIO-ECONOMIC SATISFACTIONLEVEL OF PATIENTS FOR ACRYLIC AND CAST ALLOY DENTURES

Background: The ultimate loss of dentition creates lot of oral problems for edentulous patients which can be prevented with the provision of acrylic or cast alloy denture but patient satisfaction level attributed to these dentures is still unknown. We evaluated patient satisfaction level regarding aesthetics, pain, cost, retention, comfort and speech between acrylic and cast alloy denture wearers. Methods: Freshly edentulous patients wearing complete dentures with acrylic resin denture (AD) (n=65) and Co-Cr cast alloy denture (CD) (n=65) took part in study. Smart Patient Satisfaction Questionnaire was used to investigate satisfaction of these patients after one month (AD-1 and CD-1) and then after 3 months (AD-3 and CD-3). Scoring system 0=Not-Satisfied, 1=Satisfied and 2=Well Satisfied was used to evaluate general satisfaction of patients in both groups regarding speech, taste, pain, aesthetics, comfort, cost, and retention. Results: Patient satisfaction level between AD and CD wearers displayed insignificant differences with respect to aesthetics (p=0.614), pain (p=0.842), retention (p=0.852), comfort (p=0.842), speech (p=0.943), and taste (p=0.753). Patient satisfaction level between AD and CD users related to cost was significant (p=0.001) depicting that AD group was more satisfied with cost as compared to CD users. Conclusions: Both groups were satisfied with their aesthetics, pain control, retention, comfort, speech, and taste but patients using AD were found to be more satisfied with cost as compared to CD users who found these dentures quite expensive. Pak J Physiol 2023;19(4):6-10

Construction of functional surfaces for dental implants to enhance osseointegration.

Dental implants have been extensively used in patients with defects or loss of dentition. However, the loss or failure of dental implants is still a critical problem in clinic. Therefore, many methods have been designed to enhance the osseointegration between the implants and native bone. Herein, the challenge and healing process of dental implant operation will be briefly introduced. Then, various surface modification methods and emerging biomaterials used to tune the properties of dental implants will be summarized comprehensively.

THU458 Demineralization Zebras: A Rare Case Of Hypophosphatasia In An Adult Presenting With Osteopenia

Abstract Disclosure: B.P. Ramchandani: None. A. Khan: None. H. Aftab: None. Introduction: Hypophosphatasia (HPP) is a rare genetic bone disease with only 500-600 cases reported in the United States. It is characterized by mutations in the tissue non-specific alkaline phosphatase (TNSALP) gene, leading to impaired bone mineralization. HPP presenting in the perinatal period is fatal. During infancy, rachitic deformities develop by age 6 months. Children present with early loss of deciduous teeth and delayed milestones while in adulthood, HPP is characterized by recurrent fractures, osteoporosis, and muscle weakness. We describe a case of HPP diagnosed in a patient after low ALP was discovered on laboratory testing. Case: A 69-year-old female presented for the evaluation of osteopenia. She had a history of fracture of the right knee as well as fracture of the base of the right 5th metatarsal and lateral aspect cuboid, which healed well with conservative management. Dental history was significant for 5 implants over the last 15 years. She was on vitamin D supplements and had also taken risedronate for osteopenia for 14 years which was discontinued at her first visit with us. Family history was significant for osteoporosis in her mother. Initial lab studies were significant for an ALP of 29 U/L (ref range 39-113 U/L), phosphate of 4.9 mg/d (ref range 2.4-4.8 mg/dl), pyridoxal 5’-phosphate level (vitamin B6) of 308 nmol/L (ref range 20-125 nmol/l), a vitamin D 25-OH level of 20 ng/mL (ref range >30 ng/ml) and PTH of 49 pg/dl (ref range 15-88 pg/ml). Repeat lab testing done 6 months after stopping risedronate showed consistent similar results with an ALP of 32 U/L, phosphate level of 5.1 mg/dl, vitamin B6 level of 349 nmol/L, and vitamin D 25OH level of 26 ng/mL. Bone density scan revealed a lumbar spine BMD of 1.503 g/cm2 (T-score 2.5) and a mean total hip BMD of -0.3 consistent with osteoporosis of spine and osteopenia of hip. Genetic testing and counseling were offered to the patient, however she declined. Discussion: Our patient presented with recurrent fractures and loss of dentition requiring multiple dental implants in the background of osteopenia. Given persistently low serum ALP and elevated serum vitamin B6 levels her presentation suggested a diagnosis of HPP. Management includes supportive treatment with prompt treatment of fractures, and routine dental care. Although there is no approved medication for adults, enzyme therapy replacement with asfotase-alfa (a recombinant human ALP) is FDA-approved for pediatric-onset HPP which improves bone mineralization and muscle strength, however discontinuation of therapy leads to reappearance of bone hypomineralization. Once the diagnosis is made, genetic testing and counseling should be offered to prevent complications in future pregnancies. Presentation: Thursday, June 15, 2023

Retracted: Investigation of the Effect of Oral Implant Surgery on Clinical Treatment and Oral Function of Patients with Dentition Loss.

[This retracts the article DOI: 10.1155/2022/1698842.].

Long-term trends in the burden of edentulism in China over three decades: A Joinpoint regression and age-period-cohort analysis based on the global burden of disease study 2019.

To investigate secular trends in edentulism incidence, prevalence, and years lived with disability (YLDs) rates in Chinese men and women from 1990 to 2019. Data were obtained from the Global Burden of Disease Study 2019. The annual percentage change and average annual percentage change were calculated using Joinpoint regression analysis. The age-period-cohort (APC) analysis estimated the independent age, period, and cohort effects. From 1990 to 2019, the crude incidence, prevalence, and YLDs of edentulism in the Chinese population increased year by year, while the age-standardized incidence, prevalence, and YLDs decreased, and the latter was higher in women than in men. The APC analysis showed that the age effect increased in men and women from age 20 to 74 and decreased thereafter. The risk of tooth loss increased with age. However, the relationship was not linear. The temporal effect showed a gradual increase; the risk of missing teeth gradually increased with the changing modern living environment. The cohort effect showed a single decreasing trend, with the early birth cohort having a higher risk of tooth loss than the later birth cohort population. The age, period, and cohort effects were consistent for both sexes. Although the standardized incidence, prevalence, and YLD rate and cohort effect of dentition loss in China are declining, they are still causing a severe burden to China due to the continued aging of the population and the rising period effect. Despite the decreasing trends of the standardized incidence and prevalence of dentition loss and the rate of YLDs, China should develop more effective oral disease prevention and control strategies to reduce the increasing burden of edentulism in the older adult, especially in older women.

Clinical and genetic features of Kenny-Caffey syndrome type 2 with multiple electrolyte disturbances: A case report

Hypoparathyroidism, which can be sporadic or a component of an inherited syndrome, is the most common cause of hypocalcemia. If hypocalcemia is accompanied by other electrolyte disturbances, such as hypokalemia and hypomagnesemia, then the cause, such as renal tubular disease, should be carefully identified. An 18-year-old female visited our clinic because of short stature and facial deformities, including typical phenotypes, such as low ear position, depression of the nasal bridge, small hands and feet, and loss of dentition. The lab results suggested normal parathyroid hormone but hypocalcemia. In addition, multiple electrolyte disturbances were found, including hypokalemia, hypocalcemia and hypomagnesemia. The physical signs showed a short fourth metatarsal bone of both feet. The X-ray images showed cortical thickening of long bones and narrowing of the medulla of the lumen. Cranial computed tomography indicated calcification in the bilateral basal ganglia. Finally, the genetic investigation showed a de novo heterogenous mutation of "FAM111A" (c. G1706A:p.R569H). Through a review of previously reported cases, the mutation was found to be the most common mutation site in Kenny-Caffey syndrome type 2 (KCS2) cases reported thus far (16/23, 69.6%). The mutation was slightly more prevalent in females than in males (11/16, 68.8%). Except for hypocalcemia, other clinical manifestations are heterogeneous. As a rare autosomal dominant genetic disease of hypoparathyroidism, the clinical manifestations of KCS2 are atypical and diverse. This girl presented with short stature, facial deformities and skeletal deformities. The laboratory results revealed hypocalcemia as the main electrolyte disturbance. Even though her family members showed normal phenotypes, gene detection was performed to find the mutation of the FAM111A gene and confirmed the diagnosis of KCS2.

A Boolean Network Approach to Study the Mechanism Associated with Inflammatory Response Induced by Porphyromonas gingivalis.

Anaerobic Porphyromonas gingivalis is a rod-shaped bacterium and is a primary agent of periodontal inflammation and thus periodontitis. This bacterium disturbs the normal flora of the oral cavity and causes dysbiosis. Databases including Google Scholar Scopus and PubMed were employed to find the evidence by using keywords like 'Porphyromonas gingivalis,' 'Boolean network,' 'inflammatory response and Porphyromonas gingivalis,' 'inflammation and Porphyromonas gingivalis. Only articles that reviewed the role of Porphyromonas gingivalis in oral inflammation were selected. Porphyromonas gingivalis promotes and reorganizes host immune systems against normal host flora, which causes a dysbiotic state. A reorganized immune system induces dysbiosis and periodontitis. Specifically, the role of the C5a receptor in the complement system is vital in this mechanism. P. gingivalis can change the metabolic pathways of phagocytic cells without impeding inflammation. Toll-like receptor and complement signaling are inverted by Porphyromonas gingivalis, which aids them in overcoming immunological responses. However, they sustain the inflammation process, which promotes dysbiosis. Instead of a subjective approach, a systems perspective is required to comprehend this intricate process. A Boolean network is a system approach that seems to be a better approach to understanding this complicated interaction process of Porphyromonas gingivalis with the immune system and inflammation. In short, attempts to understand the complex process using the Boolean network will ultimately help in the early detection of periodontitis, and immediate treatment can prevent soft tissue destruction and dentition loss.

History of the removable denture

Removable dentures are artificial teeth to replace a partial or complete loss of dentition.

Porphyromonas Gingivalis in the Development of Periodontitis: Impact on Dysbiosis and Inflammation.

Chronic periodontitis is an inflammatory disease of the dental plaque and affects the soft tissues supporting the tooth. It is one of the most practical oral health issues across the globe and adversely affects the quality of life. In a neutrophil-mediated action, the inflammatory response to periodontitis destroys the periodontal ligaments, gums, the alveolar bone, and the cementum. Some of the most associated invasive pathogens with periodontitis are Porphyromonas Gingivalis, Aggregatibacter actinomycetecomitans, and Fusobacterium nucleatum. Google Scholar and PubMed were used to search the evidence using key terms like 'periodontitis,' 'Porphyromonas Gingivalis,' 'Oral Dysbiosis and Periodontitis,' 'Porphyromonas Gingivalis and Periodontitis,' etc. Only studies were included reviewing the Porphyromonas Gingivalis and its role in periodontitis. It has been observed from several oral pathogens that P. gingivalis has received immense attention due to a strong association between Porphyromonas Gingivalis and periodontal disease. Porphyromonas Gingivalis also disrupts the delicate balance between various members of the oral microbial communities and promotes oral dysbiosis. The dysbiotic state of the oral microbiome is distinct in functional capabilities and shows a higher expression of genes involved in lipopolysaccharide synthesis, energy regulation, and bacterial motility. Certain virulence factors such as gingipains, LPS, and fimbriae also increase the invasion and pathogenicity of Porphyromonas Gingivalis. Its presence in the periodontal tissues increases the secretion of numerous pro-inflammatory mediators such as TNF-α, IL-8, and IL-1β, leading to the destruction of soft gingival tissues and ligaments. Early detection of periodontitis and immediate treatment can prevent soft tissue destruction and dentition loss. In conclusion, details about the oral microbiome, oral dysbiosis, and inflammation may offer new therapeutic options in the future, including a personalized approach and the use of combination therapy.

P-68027784-328 - 'Jaw-in-a-Day' simultaneous jaw reconstruction with intraoral implant surgery.

<h3>Purpose</h3> Composite defects including teeth-soft tissue-bone are caused after tumor ablation in oral and maxillofacial area and makes severe problems in diet and phonation. There have been some trials to reconstruct occlusion immediately after tumor ablation. Max et al. reported fibula reconstruction with CAD/CAM reconstruction plates and dental implants. They reported a fibula cutting guide which has holes for dental implant position. Yadranko et al. reported a 3d printed mandible model to simulated fibula segment fixation and dental implant installation. Here we report a technique using a teeth supported dental implant guide to reconstruct proper occlusion immediately. <h3>Methods</h3> Previous reported articles were reviewed. Comparison between installing implants several years after reconstruction was done. According to reports of Max et al., there were 3.3mm centerpoint deviation and 13.0 degree angular deviation of implant with their Methods. <h3>Results</h3> Reconstructing occlusion simultaneously with bone has several advantages. It dramatically shortens period of dentition loss. Soft tissue management can be done simply. In result, when installing dental implants outside the oral cavity, error due to bone positioning is inevitable. Intraoral implant surgery after fixation of bone segment is thought to reduce these errors. <h3>Conclusions</h3> Our final goal for reconstruction of oral and maxillofacial defect is not positioning bone segment properly but reconstructing proper occlusion. Even though the bone segment is positioned in a slightly different position from the planned position, intraoral implant guide using other teeth as a reference will make it possible to install implant in planned position.

Osseous surgery: Traditional vs fiber retention resective surgery

Periodontitis is a disease originating from bacteria in a susceptible host, in which a nonprotective, chronic inflammatory process results in the destruction of supporting soft and hard tissues surrounding the teeth, eventually causing the loss of dentition over time. The ultimate goal of periodontal treatment is to control the progression of periodontal disease. This is achieved by removing the causative factors and stopping progression of clinical attachment loss and ultimately preventing loss of teeth. Osseous resective surgery (ORS) is one of the treatment modalities used to gain access to the root surfaces and boney defects, visualize removal of plaque and calculus from the root surfaces, and reestablish proper bone and soft tissue contours in order to facilitate removal of plaque by the patient as well as dental professionals. Osseous resective surgery fiber retention (FibReORS) is another less commonly used variation of this resective approach. Although it has shown promising results, little research exists comparing the two approaches. The aim of this review is to revisit the dogma of traditional ORS and highlight the differences between the two surgical approaches in regard to clinical procedures, clinical outcomes, and patient's reported outcomes.

COMPARATIVE EVALUATION OF THE ANGULAR DIMENSIONS OF THE MANDIBLE WITH VARYING DEGREES OF PRESERVATION OF THE DENTITION IN MEN AND WOMEN OF THE MATURUSAGE GROUPS (FROM 35 TO 55 YEARS) AND SENILIS(OVER 56 YEARS OLD)

Resume. The study of the features of the structure of the lower jaw with preserved and with various degrees of loss of dentition is relevant from the point of view of dental implantology. Materials and methods. A craniometric study of angular dimensions was carried out on 120 3D models of the mandibles of men and women of the age groups Maturus and Senilis, divided into 10 subgroups. The degree of influence of tooth loss on angular dimensions was assessed. Results. In groups with complete acquired adentia, there was a statistically significant decrease in the angles of inclination and protrusion of the chin in men and women from 6° to 14° (p &lt; 0,05), while in other groups with partial adentia, no statistically significant differences were observed. The angle of the lower jaw branch and the basal angle did not respond to tooth loss. Conclusions. The anterior segment of the lower jaw body undergoes maximum restructuring, which is reflected in the reaction of angular dimensions to the complete loss of teeth

Investigation of the Effect of Oral Implant Surgery on Clinical Treatment and Oral Function of Patients with Dentition Loss.

In order to investigate the effect of oral implant surgery on clinical treatment and oral function of patients with dentition loss, a total of 118 patients with dentition loss in the Department of Stomatology of our hospital from January 2019 to January 2022 are retrospectively analyzed. They are randomly divided into the conventional group and the implant group. The conventional group is treated with conventional dentition restoration, and the implant group is treated with oral implant restoration. The repair efficiency of the two groups is compared. The swallowing function of the 2 groups is assessed by Standard Swallowing Assessment (SSA) table before and after treatment. Self-rating depression scale (SDS) and self-rating anxiety scale (SAS) are used to compare the negative emotions of the two groups before and after treatment. Experimental results show that the total effective rate of the implant group is significantly higher than that of the conventional group, but no invalid cases occurred in the two groups after treatment.

The remarkable dynamics in the establishment, rearrangement, and loss of dentition during the ontogeny of the sterlet sturgeon.

Sturgeons belong to an early-branching lineage often used as a proxy of ancestor-like traits of ray-finned fishes. However, many features of this lineage, such as the transitory presence and the eventual loss of dentition, exemplify specializations that, in fact, provide important information on lineage-specific evolutionary dynamics. Here, we introduce a detailed overview of the dentition during the development of the sterlet sturgeon. The dentition is composed of tooth fields at oral, palatal, and anterior pharyngeal regions. Oral fields are single-rowed, non-renewed and are shed early. Palatal and pharyngeal fields are multi-rowed and renewed from the adjacent superficial epithelium without the presence of the successional dental lamina. The early loss of oral fields and subsequent establishment of palatal and pharyngeal fields leads to a translocation of the functional dentition from the front to the rear of the oropharyngeal cavity until the eventual loss of all teeth. Our survey shows the sterlet dentition as a dynamic organ system displaying differential composition at different time points in the lifetime of this fish. These dynamics represent a conspicuous feature of sturgeons, unparalleled among extant vertebrates, and appropriate to scrutinize developmental and evolutionary underpinnings of vertebrate odontogenesis.

Immediate precision of the digital osteotomy template in the digital stackable template: a clinical study.

This study aimed to evaluate the immediate accuracy of the digital osteotomy template in the digital stackable template. From November 2018 to January 2020, 4 patients with dentition loss were selected from the Prosthodontics Department, West China Stomatological Hospital. All patients met the conditions for immediate planting and immediate restoration. Owing to the lack of vertical target-restoration space, the implantation plan included intraoperative osteotomy. According to the preoperative cone beam CT (CBCT) data, combined with aesthetic digital smile design (DSD) analysis, virtual wax design, and so on, the ideal bone plane design was performed. According to the virtual osteotomy plane, the virtual implantation plan was designed, and then the digital stackable template assuming osteotomy template, implantation guide, and temporary restoration were made and 3D printed. Osteotomy was performed under the guidance of digital osteotomy template during the operation. The preoperative CBCT and postoperative CBCT of all patients overlapped, the deviation between the actual osteotomy and the ideal osteotomy was calculated, and the angle deviation between the postoperative bone plane and the ideal bone plane was measured. The ave-rage volume deviation between the postoperative design and the ideal one was 492.94 mm³, accounting for 21.21% of the preset osteotomy volume. The average deviation between the postoperative osteotomy and the ideal osteotomy in four patients was 0.024 8 mm. The average angle between the postoperative bone plane and the ideal bone plane was 6.03°. The displacement deviation of virtual osteotomy design and the actual osteotomy one under the guidance of digital osteotomy template in the digital stackable template are highly consistent with the original design. Thus, this clinical technique is worth popularizing, accurate, and quantifiable.

Dental loss after radiotherapy for head and neck cancer.

Introduction In radiotherapy (RT) for head and neck cancer (HNC), dental morbidity is significant and it may result in loss of the dentition following treatment.Aims The aim of this clinical study is to identify the incidence of tooth loss over time and correlate this to the RT dose and various risk factors in patients with HNC treated with radical RT.Design A retrospective observational study.Materials and methods The records of 1,118 patients with HNC treated with radical or adjuvant RT from January 2010 to December 2019 were analysed. After applying strict inclusion criteria, 78 patients with 1,566 individual tooth data were selected. RT dose mapping was performed for each tooth.Results A total of 253 teeth (16.2%) were extracted. The following risk factors were significant: gender (p = 0.0001), xerostomia (p <0.0001), RT dose (p <0.0001) and smoking (p <0.0001). Non-significant factors were age, RT delivery technique and the addition of cisplatin.Conclusion Detailed RT dose mapping was used to identify RT dose as a risk factor for dental loss. Careful pre-RT dental treatment and minimisation of RT dose to teeth and salivary glands is required to prevent or reduce the loss of dentition.

Is Gutta-Percha Still the “Gold Standard” among Filling Materials in Endodontic Treatment?

The paper is an extensive monographic review of the literature, and also uses the results of the authors’ own experimental research illustrating the noticed developmental tendencies of the filling material based on gutta-percha. The whole body of literature proves the correctness of the research thesis that this material is the best currently that can be used in endodontics. Caries is one of the most common global infectious diseases. Since the dawn of humankind, the consequence of the disease has been the loss of dentition over time through dental extractions. Both tooth caries and tooth loss cause numerous complications and systemic diseases, which have a serious impact on insurance systems and on the well-being, quality, and length of human life. Endodontic treatment, which has been developing since 1836, is an alternative to tooth extraction. Based on an extensive literature review, the methodology of qualifying patients for endodontic treatment was analyzed. The importance of selecting filling material and techniques for the development and obturation of the root canal during endodontic treatment was described. Particular attention was paid to the materials science aspects and the sequence of phase transformations and precipitation processes, as well as the need to ensure the stoichiometric chemical composition of Ni–Ti alloys, and the vacuum metallurgical processes and material processing technologies for the effects of shape memory and superelasticity, which determine the suitability of tools made of this alloy for endodontic purposes. The phenomena accompanying the sterilization of such tools, limiting the relatively small number of times of their use, play an important role. The methods of root canal preparation and obturation methods through cold side condensation and thermoplastic methods, including the most modern of them, the thermo-hydraulic condensation (THC) technique, were analyzed. An important element of the research hypothesis was to prove the assumption that to optimize the technology of development and obturation of root canals, tests of filling effectiveness are identified by the density and size of the gaps between the root canal wall, and the filling methods used and devices appropriate for material research, using mainly microscopy such as light stereoscopic (LSM) and scanning electron (SEM). The most beneficial preparations were obtained by making a longitudinal breakthrough of 48 natural human teeth, extracted for medical reasons, different from caries, with compliance with all ethical principles in this field. The teeth were prepared using various methods and filled with multiple obturation techniques, using a virtual selection of experimental variants. The breakthroughs were made in liquid nitrogen after a one-sided incision with a narrow gap created by a diamond disc using a materialographic cutter. The best effectiveness of the root canal filling was ensured by the technology of preparing the root canals with K3 rotary nitinol tools and filling the teeth with the THC thermoplastic method using the System B and Obtura III devices with studs and pellets of filling material based on gutta-percha after covering the root canal walls with a thin layer of AH Plus sealant. In this way, the research thesis was confirmed.

Clinical Effect and Aesthetic Observation of All-on-4 Immediate Loading Implant Denture in Severe Periodontitis.

Objective To explore the clinical effect and aesthetics of All-on-4 immediate loading implant denture in severe periodontitis. Methods Totally, 60 patients with dentition loss caused by severe periodontitis who were admitted to our hospital from February 2017 to February 2019 were selected. The patients were randomly divided into the observation group (n = 30) and the control group (n = 30) according to different restoration methods. The control group was used in traditional implant restoration treatment, and the observation group was used in All-on-4 immediate loading implant denture restoration. The clinical effect, periodontal index, aesthetic effect, and complications of the two groups were compared, and the levels of serum leptin (LEP), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), and interleukin-6 (IL-6) were measured. Results The total effective rate of the observation group (83.33%) was higher than that of the control group (60.00%) (P < 0.05). After treatment, the plaque index, gingival sulcus bleeding index, and depth of exploration of the two groups were lower than those before treatment (P < 0.05), and there was no significant difference between the two groups (P > 0.05). After treatment, the serum LEP, TNF-α, CRP, and IL-6 in both groups were lower than before treatment, and the serum LEP, TNF-α, CRP, and IL-6 in the observation group were lower than that in the control group (P < 0.05). The aesthetic rate of teeth in the observation group (90.00%) was higher than that in the control group (66.67%) (P < 0.05). There was no significant difference in the total incidence of complications between the two groups (P > 0.05). Conclusion All-on-4 immediate loading implant denture has a good effect in the treatment of severe periodontitis, which is conducive to maintaining periodontal health, reducing the level of inflammation, improving aesthetics, and has high safety.

Pseudogenized Amelogenin Reveals Early Tooth Loss in True Toads (Anura: Bufonidae).

Extant anurans (frogs and toads) exhibit reduced dentition, ranging from a lack of mandibular teeth to complete edentulation, as observed in the true toads of the family Bufonidae. The evolutionary time line of these reductions remains vague due to a poor fossil record. Previous studies have demonstrated an association between the lack of teeth in edentulous vertebrates and the pseudogenization of the major tooth enamel gene amelogenin (AMEL) through accumulation of deleterious mutations and the disruption of its coding sequence. In this study, we have harnessed the pseudogenization of AMEL as a molecular dating tool to correlate loss of dentition with genomic mutation patterns during the rise of the family Bufonidae. Specifically, we have utilized AMEL pseudogenes in three members of the family as a tool to estimate the putative date of edentulation in true toads. Comparison of AMEL sequences from Rhinella marina, Bufo gargarizans and Bufo bufo, with nine extant, dentulous frogs, revealed mutations confirming AMEL inactivation in Bufonidae. AMEL pseudogenes in modern bufonids also exhibited remarkably high 86-93% sequence identity among each other, with only a slight increase in substitution rate and relaxation of selective pressure, in comparison with functional copies in other anurans. Moreover, using selection intensity estimates and synonymous substitution rates, analysis of functional and pseudogenized AMEL resulted in an estimated inactivation window of 46-60 million years ago in the lineage leading to modern true toads, a time line that coincides with the rise of the family Bufonidae.

Dental Implants Loaded With Bioactive Agents Promote Osseointegration in Osteoporosis: A Review

Implant-supported dentures are widely used in patients with defect or loss of dentition because these have higher chewing efficiency and do not damage the adjacent teeth compared with fixed or removable denture. An implant-supported denture carries the risk of failure in some systemic diseases, including osteoporosis, because of a non-ideal local microenvironment. Clinically common physical and chemical modifications are used to change the roughness of the implant surface to promote osseointegration, but they have limitations in promoting osteoinduction and inhibiting bone resorption. Recently, many researchers have focused on the study of bioactive modification of implants and have achieved promising results. Herein we have summarized the progress in bioactive modification strategy to promote osseointegration by regulating the local osteoporotic microenvironment.