Mutated CCDC51 Coding for a Mitochondrial Protein, MITOK Is a Candidate Gene Defect for Autosomal Recessive Rod-Cone Dystrophy.

The purpose of this work was to identify the gene defect underlying a relatively mild rod-cone dystrophy (RCD), lacking disease-causing variants in known genes implicated in inherited retinal disorders (IRD), and provide transcriptomic and immunolocalization data to highlight the best candidate. The DNA of the female patient originating from a consanguineous family revealed no large duplication or deletion, but several large homozygous regions. In one of these, a homozygous frameshift variant, c.244_246delins17 p.(Trp82Valfs*4); predicted to lead to a nonfunctional protein, was identified in CCDC51. CCDC51 encodes the mitochondrial coiled-coil domain containing 51 protein, also called MITOK. MITOK ablation causes mitochondrial dysfunction. Here we show for the first time that CCDC51/MITOK localizes in the retina and more specifically in the inner segments of the photoreceptors, well known to contain mitochondria. Mitochondrial proteins have previously been implicated in IRD, although usually in association with syndromic disease, unlike our present case. Together, our findings add another ultra-rare mutation implicated in non-syndromic IRD, whose pathogenic mechanism in the retina needs to be further elucidated.

Effect of Medical-Grade Polyurethane Sponges on Sinus Membrane Perforation With a Lateral Window Approach.

The most commonly reported complication during the sinus elevation surgical procedure is the perforation of the Schneiderian membrane. The aim of this retrospective study was to compare the rate of sinus membrane perforation during lateral window augmentation using either conventional sinus curettes or medical-grade polyurethane sponges. This retrospective study included patients who received a lateral window approach for sinus floor elevation. The sinus elevation procedures using medical-grade polyurethane sponges (test) or conventional curettes (control) were recorded and analyzed. All subjects' demographic data and preexisting conditions were evaluated. A total of 38 procedures met inclusion criteria, and those data were evaluated for analysis. There were no statistically significant differences in demographic data or preexisting conditions including age, sex, treatment location, presence and absence of septum, Schneiderian membrane thickness, and residual bone height between test and control groups. The membrane perforation rate was 7% in the test group and 43% in the control group; however, this difference did not reach statistical significance (P = .064). Within the limitations of this study, although there was no statistically significant reduction of sinus membrane perforation with the use of medical-grade polyurethane sponges, the decreased incidence of perforation might be of clinical significance.

Levels of growth factors from platelet-rich fibrin from chronic periodontitis versus periodontally healthy subjects: a pilot study.

OBJECTIVES: This study aimed to (1) compare the amounts of growth factors from platelet-rich fibrin (PRF) between chronic periodontitis and periodontally healthy subjects and (2) evaluate the relationships between the amounts of growth factors from PRF with complete blood counts (white blood cell (WBC) and platelet counts) and the serum concentrations of IL-1ß, IL-6, and tumor necrosis factor-α (TNF-α). MATERIALS AND METHODS: Venous blood was collected from chronic periodontitis (test) and periodontally healthy subjects (control). PRF and serum were collected from the centrifuged blood. Liquid exudates from the compression of PRF were collected. The compressed PRF membranes were incubated in saline, and eluted aliquots were collected at 1, 24, and 72 h, and the membranes were then digested with trypsin. Epidermal growth factor, insulin-like growth factor-1, platelet-derived growth factor-BB, transforming growth factor-ß1, and vascular endothelial growth factor in the exudates and eluents were quantified by ELISA. Serum was used for IL-1ß, IL-6, and TNF-α quantifications. Complete blood counts were measured. RESULTS: There were no significant differences in the amounts of growth factors from PRF exudates and membranes measured between groups (all p > 0.05). The test group had significantly higher WBC (p < 0.05). However, there was no significant correlation between the WBC and the amounts of the growth factors from PRF (all p > 0.05). CONCLUSIONS: PRF can be utilized as an autologous source of growth factors not affected by periodontal condition and WBC level. CLINICAL RELEVANCE: The amounts of growth factors from PRF were not affected by the periodontal condition of the patient.

Where are the missing gene defects in inherited retinal disorders? Intronic and synonymous variants contribute at least to 4% of CACNA1F-mediated inherited retinal disorders.

Inherited retinal disorders (IRD) represent clinically and genetically heterogeneous diseases. To date, pathogenic variants have been identified in ~260 genes. Albeit that many genes are implicated in IRD, for 30-50% of the cases, the gene defect is unknown. These cases may be explained by novel gene defects, by overlooked structural variants, by variants in intronic, promoter or more distant regulatory regions, and represent synonymous variants of known genes contributing to the dysfunction of the respective proteins. Patients with one subgroup of IRD, namely incomplete congenital stationary night blindness (icCSNB), show a very specific phenotype. The major cause of this condition is the presence of a hemizygous pathogenic variant in CACNA1F. A comprehensive study applying direct Sanger sequencing of the gene-coding regions, exome and genome sequencing applied to a large cohort of patients with a clinical diagnosis of icCSNB revealed indeed that seven of the 189 CACNA1F-related cases have intronic and synonymous disease-causing variants leading to missplicing as validated by minigene approaches. These findings highlight that gene-locus sequencing may be a very efficient method in detecting disease-causing variants in clinically well-characterized patients with a diagnosis of IRD, like icCSNB.

LinkageMapView-rendering high-resolution linkage and QTL maps.

MOTIVATION: Linkage and quantitative trait loci (QTL) maps are critical tools for the study of the genetic basis of complex traits. With the advances in sequencing technology over the past decade, linkage map densities have been increasing dramatically, while the visualization tools have not kept pace. LinkageMapView is a free add-on package written in R that produces high resolution, publication-ready visualizations of linkage and QTL maps. While there is software available to generate linkage map graphics, none are freely available, produce publication quality figures, are open source and can run on all platforms. LinkageMapView can be integrated into map building pipelines as it seamlessly incorporates output from R/qtl and also accepts simple text or comma delimited files. There are numerous options within the package to build highly customizable maps, allow for linkage group comparisons, and annotate QTL regions. AVAILABILITY AND IMPLEMENTATION: https://cran.r-project.org/web/packages/LinkageMapView/.

Whole exome sequencing resolves complex phenotype and identifies CC2D2A mutations underlying non-syndromic rod-cone dystrophy.

Genetic investigations were performed in three brothers from a consanguineous union, the two oldest diagnosed with rod-cone dystrophy (RCD), the youngest with early-onset cone-rod dystrophy and the two youngest with nephrotic-range proteinuria. Targeted next-generation sequencing did not identify homozygous pathogenic variant in the oldest brother. Whole exome sequencing (WES) applied to the family identified compound heterozygous variants in CC2D2A (c.2774G>C p.(Arg925Pro); c.4730_4731delinsTGTATA p.(Ala1577Valfs*5)) in the three brothers with a homozygous deletion in CNGA3 (c.1235_1236del p.(Glu412Valfs*6)) in the youngest correcting his diagnosis to achromatopsia plus RCD. None of the three subjects had cerebral abnormalities or learning disabilities inconsistent with Meckel-Gruber and Joubert syndromes, usually associated with CC2D2A mutations. Interestingly, an African woman with RCD shared the CC2D2A missense variant (c.2774G>C p.(Arg925Pro); with c.3182+355_3825del p.(?)). The two youngest also carried compound heterozygous variants in CUBN (c.7906C>T rs137998687 p.(Arg2636*); c.10344C>G p.(Cys3448Trp)) that may explain their nephrotic-range proteinuria. Our study identifies for the first time CC2D2A mutations in isolated RCD and underlines the power of WES to decipher complex phenotypes.

Pathview Web: user friendly pathway visualization and data integration.

Pathway analysis is widely used in omics studies. Pathway-based data integration and visualization is a critical component of the analysis. To address this need, we recently developed a novel R package called Pathview. Pathview maps, integrates and renders a large variety of biological data onto molecular pathway graphs. Here we developed the Pathview Web server, as to make pathway visualization and data integration accessible to all scientists, including those without the special computing skills or resources. Pathview Web features an intuitive graphical web interface and a user centered design. The server not only expands the core functions of Pathview, but also provides many useful features not available in the offline R package. Importantly, the server presents a comprehensive workflow for both regular and integrated pathway analysis of multiple omics data. In addition, the server also provides a RESTful API for programmatic access and conveniently integration in third-party software or workflows. Pathview Web is openly and freely accessible at https://pathview.uncc.edu/.

Novel splice-site mutation in TTLL5 causes cone dystrophy in a consanguineous family.

PURPOSE: To report the clinical and genetic findings of one family with autosomal recessive cone dystrophy (CD) and to identify the causative mutation. METHODS: An institutional study of three family members from two generations. The clinical examination included best-corrected Snellen visual acuity measurement, fundoscopy, the Farnsworth D-15 color vision test, a full-field electroretinogram (ERG) that incorporated the International Society for Clinical Electrophysiology of Vision standards and methodology, fundus autofluorescence (FAF) and infrared (IR), and spectral-domain optical coherence tomography (SD-OCT). Genetic findings were achieved with DNA analysis using whole exome sequencing (WES) and Sanger sequencing. RESULTS: The proband, a 9-year-old boy, presented with a condition that appeared to be congenital and stationary. The clinical presentation initially reflected incomplete congenital stationary night blindness (icCSNB) because of myopia, a decrease in visual acuity, abnormal oscillatory potentials, and reduced amplitudes on the 30 Hz flicker ERG but was atypical because there were no clear electronegative responses. However, no disease-causing mutations in the genes underlying icCSNB were identified. Following WES analysis of family members, a homozygous splice-site mutation in intron 3 of TTLL5 (c.182-3_182-1delinsAA) was found cosegregating within the phenotype in the family. CONCLUSIONS: The distinction between icCSNB and CD phenotypes is not always straightforward in young patients. The patient was quite young, which most likely explains why the progression of the CD was not obvious. WES analysis provided prompt diagnosis for this family; thus, the use of this technique to refine the diagnosis is highlighted in this study.

The Effects of Clockwise and Counterclockwise Conventional and Osseodensification Drilling on the Dimensions, Density, and Biomechanical Properties of Bone.

Purpose: To compare the effects of regular implant drills to osseodensifying drills used in clockwise and counterclockwise motions on bone dimension change and primary implant stability. Materials and Methods: A total of 40 bone models were made (20 × 15 × 4 mm) from porcine tibia to represent implants placed in soft bone. Implant osteotomies were prepared in the bone models using one of the following techniques: (1) regular implant drills in a clockwise direction (group A), (2) regular implant drills in a counterclockwise direction (group B), (3) osseodensifying drills in a clockwise direction (group C), and (4) osseodensifying drills in a counterclockwise direction (group D). Bone-level tapered titanium alloy implants (4.1 × 10 mm) were placed following osteotomy creation. The implant stability quotient (ISQ) was measured after implant placement. Each bone model was scanned with an optical scanner to convert to Standard Tessellation Language (STL) files before and after the osteotomy creation. Presurgical and postsurgical STL files were superimposed, and the dimensional changes were measured at 1, 3, and 7 mm from the crestal bone. Histomorphometric analysis was done, and bone-to-implant contact percentage (BIC%) was calculated. Results: There were no significant differences in ISQ values (P = .239) between any of the groups. Histomorphometric analysis showed implants in group D had significantly higher BIC% than groups A (P = .020) and B (P = .009). The amount of bone expansion decreased with distance from the crest (P < .001). Groups B (P = .039) and D (P = .001) showed significant expansions at all levels compared with group A. No other statistically significant differences in dimensional change were found between groups. Conclusion: Both regular and osseodensification burs used in a counterclockwise motion contribute to expansion of bone dimension compared to conventional drilling methods.

Histologic and Histomorphometric Analyses of Peri-implant Bone from Loaded Dental Implants: A Case Report

The histological findings and histomorphometrical analyses of peri-implant tissues from nine functionally loaded dental implants from an adult cadaver were analyzed. Despite the presence of peri-implant bone loss, all implants were found to have a high degree of osseointegration, with the bone-implant contact (BIC) ranging from 69% to 88%. The mean value of the BIC was 83.2 ± 4.3% (range: 76.5 - 87.7%) for the maxillary implants and 74.4 ± 7.1% (range: 69.4 - 84.9%) for the mandibular implants. The BIC was comparable for maxillary and mandibular implants. Relatively prominent bone remodeling and resorption with soft tissue ingrowth were observed in the vertical bony defects compared to the areas without intrabony components, which might represent the sequence of bone loss around the dental implants.

Comparison of In Vitro Biofilm Formation on Titanium and Zirconia Implants.

Background: Peri-implant diseases are emerging issues in contemporary implant dentistry. As biofilms play a critical role in peri-implant diseases, the characteristic of resisting bacterial adhesion would be ideal for dental implants. The aims of the study were to compare titanium (Ti) and zirconia (Zr) implants regarding the amount of biofilm formation at different time frames and assess the distribution of biofilm on different aspects of dental implants. Methods: Biofilm was developed on Ti and Zr dental implants with a peri-implant-related multispecies model with Streptococcus oralis, Actinomyces naeslundii, Veillonella dispar, and Porphyromonas gingivalis, for 3 and 14 days. Quantitative assessment was performed with the measurement of total bacterial viability (colony forming units, CFU/mg). Scanning electron microscopy (SEM) was used to evaluate biofilm formation on different aspects of the implants. Results: Three-day-old biofilm on Ti implants was significantly higher than that on Zr implants (p < 0.001). The Ti and Zr groups were not significantly different for 14-day-old biofilm. SEM images demonstrated that 3-day-old biofilm on Zr implants was sparse while biofilm growth was more pronounced for 3-day-old biofilm on Ti implants and 14-day-old biofilm groups. It appeared that less biofilm formed on the valley compared to the thread top for 3-day-old biofilm on Zr implants. Differences between the valley and the thread top became indistinguishable with the development of mature biofilm. Conclusion: While early formed biofilms show greater accumulation on Ti implants compared to Zr implants, older biofilms between the two groups are comparable. The distribution of biofilms was not uniform on different areas of implant threads during early biofilm development.

Dental laser training and education in postgraduate periodontics programs in North America.

INTRODUCTION: The application of various lasers to treat periodontal and peri-implant diseases is gaining momentum. While laser-related dental research is ongoing, it is important to determine if current periodontal training programs are keeping pace with these new treatment modalities and actively incorporating them into their training. MATERIALS AND METHODS: An electronic survey was created to evaluate the extent to which lasers are currently being used in North American periodontal programs. A brief explanation of the study and a link to the 15-question survey was emailed to 61 periodontal program directors requesting participation in the survey. The data regarding the prevalence of laser training in all the programs, which types of laser devices are used, and which surgical procedures are performed were collected and analyzed. RESULTS: The response rate was 49.1% (n = 30). Among those responding to the survey, 76.7% (n = 23) of these programs reported providing clinical training in lasers, with the diode laser being the most frequently used (65.2%), followed by carbon dioxide (39.1%), neodymium-doped yttrium aluminum garnet (26.1%), and erbium:yttrium aluminum garnet lasers (26.1%). Two major reasons for not utilizing lasers as part of regular patient care were cost and lack of evidence to support laser efficacy. Three out of seven programs that do not currently use lasers plan to provide laser training in the future. Over half (56.7%) of program directors did not think that lasers would become the standard of periodontal/implant care within the next 10 years, while 20% of them believed that they would. CONCLUSIONS: Laser training and education in postgraduate periodontal programs is still limited, and the majority of periodontal residents are not exposed to many types of laser devices.

Periodontal diagnosis and treatment planning - An assessment of the understanding of the new classification system.

OBJECTIVES: Substantial variations are seen among clinicians in the diagnosis and treatment planning of periodontal diseases. Accurate diagnosis and treatment planning are fundamental requirements for effective outcome-based patient care. The aim of this study was to evaluate the understanding of the American Academy of Periodontology and the European Federation of Periodontology 2017 periodontal disease classifications in diagnoses and treatment plans across four study groups. METHODS: The study recruited at least 20 participants in each of the four study groups. These included 1) Periodontal faculty and residents at Indiana University School of Dentistry (IUSD-PF) 2) IUSD general practice faculty (IUSD-GPF), 3) private practice periodontists (PPP), and 4) general practitioners (GP). The participants were provided with 10 HIPPA de-identified case records and a link to a survey. The survey comprised five demographic questions and two questions on diagnosis and treatment plan for each case along with a fixed list of responses. The responses were then compared against gold standards that were determined by a group of three board-certified periodontists. RESULTS: Overall, for diagnostic questions, GP (69%) were correct significantly less often than IUSD-PF (86%, p < 0.001), IUSD-GPF (79%, p = 0.002), and PPP (80%, p = 0.001). No significant differences (p > 0.05) in the overall correct treatment plan responses were found among the four groups (IUSD-PF: 69%, IUSD-GPF: 62%, PPP: 68%, and GP: 60%). The multi-rater kappas for with-in-group agreement on overall diagnosis ranged from 0.36 (GP) to 0.55 (IUSD-PF) and on overall treatment plan ranged from 0.32 (IUSD-GPF) to 0.42 (IUSD-PF). Overall agreement for diagnosis and treatment plans among the four groups was relatively low and none of the groups were statistically different from each other (p > 0.05). CONCLUSION: Regular participation in calibration sessions may lead to more accurate adoption of the 2017 periodontal classification and thereby help provide consistent diagnosis and treatment.

In vitro comparison of root surface roughness and bacterial adhesion following treatment with three different instruments.

BACKGROUND: A novel device, piezoelectric 11 Gracey curet tip, reportedly combines benefits of a piezoelectric device and manual curet. The primary objective of this study was to compare root surface roughness outcomes between traditional manual curets and piezoelectric devices, as compared with this novel device. The secondary aim was to assess the level of adhesion of Streptococcus mutans on the root surface after instrumentation. METHODS: The groups consisted of the following: 1) Gracey curet; 2) piezoelectric scaler; 3) piezoelectric 11 Gracey curet tip; and 4) untreated control. Root specimens were obtained from extracted human teeth and randomly assigned to each group. Surface roughness measurements (Ra and Rz) were taken with a profilometer before and after instrumentation. After instrumentation, root specimens were inoculated with S. mutans and biofilm was dislodged. Various dilutions of resuspended biofilm were incubated on blood agar plates and colony forming units (CFU) values were measured. RESULTS: The experimental device resulted in significantly lower Ra and Rz compared with other groups (P < 0.01), and the Gracey curet was significantly lower than the piezoelectric tip and untreated control (P < 0.05). The Gracey curet and experimental device tip had significantly lower CFU values compared with the control (P < 0.05). There were no significant CFU value differences between the Gracey curet and both the piezoelectric and experimental device tips. There were no significant CFU differences between piezoelectric tip and both experimental device and control. There was no correlation between Ra and CFU values for Gracey curet, piezoelectric tip, or the control. However, correlation between Ra values and CFU approached significance for the experimental device (correlation = 0.66, P = 0.05). CONCLUSIONS: Piezoelectric 11 Gracey curet tip is effective at resulting in a significantly smoother surface compared with traditional piezoelectric and hand instruments. CFU values with piezoelectric 11 Gracey curet tip were significantly lower than non-instrumented surfaces, but there were no significant differences compared with conventional methods.

Evaluation of the accuracy of soft tissue thickness measurements with three different methodologies: An in vitro study.

BACKGROUND: Soft tissue thickness (STT) influences esthetics, peri-implant, and periodontal health. Non-invasive methods of STT evaluation include cone-beam computed tomography (CBCT) with Digital Imaging and Communications in Medicine (DICOM) files and registration of DICOM files with an intraoral scan or Standard Tessellation Language (STL) files. This study compares three methodologies: bone sounding, DICOM data alone, and DICOM and STL registration to absolute histomorphologic values. METHODS: Five human maxillas, including teeth numbers 6 to 11, provided 90 sites for analysis. For standardization, reference grooves were placed at the cervical margin and the long axis of each tooth. Direct measurements with a no. 25 K-file were completed at the facial soft tissues at 3.00, 5.00, and 7.00 mm from the apical marginal reference. Indirect measures were performed with implant planning software. Histological measurements were rendered with imaging software. One-way analysis of variance (ANOVA) was used to compare the three techniques for the differences from histologic measurements (α = 0.05). RESULTS: Seventy-two sites were included for final analysis. The overall mean histological STT (mSTT) was 0.73 ± 0.31 mm. Bone sounding overestimated mSTT, 0.22 ± 0.20 mm (P < 0.001); whereas, DICOM alone underestimated mSTT, -0.23 ± 0.19 mm (P < 0.001). DICOM and STL registration had non-statistically significant differences, -0.04 ± 0.21 mm (P = 0.429). Intraclass correlation coefficient (ICC) of DICOM and STL registration achieved the highest agreement with histology (ICC: 0.74). CONCLUSIONS: DICOM and STL file registration had the highest agreement with histological STT supporting the use of DICOM and STL registration for the evaluation of STT.

An in vitro comparison of four antibacterial agents with and without nicotine and their effects on human gingival fibroblasts.

BACKGROUND: The purpose of the study was to compare anti-bacterial activity of 0.12% chlorhexidine (CHX), 10% povidone iodine (PVD), Vega oral care gel (VEGA), and antioxidant gel (AO) on Streptococcus mutans, Streptococcus sanguis, Fusobacterium nucleatum, and Porphyromonas gingivalis with and without nicotine and to evaluate their effects on human gingival fibroblasts (HGFs). METHODS: S. mutans, S. sanguis, P. gingivalis, and F. nucleatum were incubated with serial dilutions (1/4, 1/8, 1/16, 1/32, and 1/64) of anti-bacterial agents in media (with and without nicotine). Minimum inhibitory and minimum bactericidal concentrations (MIC/MBC) were measured, and confocal microscopy was performed.  HGFs were exposed to serial dilutions (1/10, 1/100, 1/1000, and 1/10,000) of antibacterial agents with media. Water-soluble tetrazolium-1 (WST-1) assay and lactate dehydrogenase (LDH) assay were used to assess proliferation and cytotoxicity towards HGFs. RESULTS: CHX and PVD significantly inhibited growth of all bacterial species (P < 0.0001) at all dilutions. AO and VEGA inhibited growth of all bacterial species up to only the 1/4 dilution. CHX and PVD decreased HGF proliferation at 1/10 and 1/100 dilution, whereas AO at all dilutions (P < 0.05). CHX and AO were cytotoxic at all dilutions (P < 0.05). VEGA was not cytotoxic to HGFs and did not affect HGF proliferation at any dilution (P > 0.05). An increased bacterial growth was seen for all species except P. gingivalis with addition of nicotine. CONCLUSION: CHX and PVD demonstrate superior antibacterial properties, but significantly reduce HGF proliferation. AO is bacteriostatic at lower dilutions but is highly toxic to HGFs. VEGA was bacteriostatic and demonstrated no detrimental effects on HGF's.

Diagnosis and treatment planning using the 2017 classification of periodontal diseases among three dental schools.

OBJECTIVES: The American Academy of Periodontology and the European Federation of Periodontology developed a new classification system for periodontal diseases in 2017. The next step in its widespread implementation involves training dental students to improve consistency in clinical decisions. This study conducted in 2020-2021 aimed to evaluate knowledge in periodontal diagnosis and treatment planning using the new classification, among first, second, third- and fourth-year dental students at Indiana University School of Dentistry (IUSD), University of Texas School of Dentistry at Houston (UTSD), and University of Louisville School of Dentistry (ULSD). METHODS: A minimum of 20 dental students per class year from each of the three schools participated. Ten HIPPA de-identified case records and a questionnaire with a fixed list of answer options, comprising two demographic questions and two questions on diagnosis and treatment planning of each case, were presented to the participants. A group of three board-certified periodontists established the answers for all cases which were used to score the appropriateness of diagnosis and treatment planning among the participants. RESULTS: A total of 263 students participated. Overall, 22.6% of IUSD responses, 25.2% of UTSD, and 27.6% of ULSD responses were correct for diagnosis (no statistically significant differences). For the treatment plan, 64.9% of IUSD responses, 66.2% of UTSD, and 68.9% of ULSD responses were correct (no statistically significant differences). CONCLUSION: Based on the findings from our study, we suggest that additional training be considered to improve the understanding of the 2017 classification of periodontal and peri-implant diseases among dental students.

Peripheral quantitative computer tomographic, histomorphometric, and removal torque analyses of two different non-coated implants in a rabbit model.

OBJECTIVE: The objectives of this study were (1) to investigate the bone-tissue response to zirconia and titanium implants at the implant-to-bone interface and at the periosteal level and (2) to quantitatively measure the mineral density of the peri-implant bone using peripheral quantitative computer tomography (pQCT). MATERIAL AND METHODS: Ten 3.5 mm × 6.6 mm screw-shaped threaded implants fabricated from titanium and zirconia were inserted into the mid-tibial diaphysis of five male New Zealand white rabbits. Calcein green was administered at 4 weeks post-implantation. The animals were sacrificed after 6 weeks and implants were retrieved and analyzed in terms of bone-to-implant contact (BIC), bone area (BA), mineralized surface (MS) percentage, inter-thread calcein labels, removal torque (RT) values, as well as pQCT measurements. FINDINGS: No statistically significant differences were detected between the zirconia and titanium implants in terms of BIC, RT, and pQCT. However, statistically significant higher BA and MS levels were found in the titanium group, while the higher amount of calcein labels occupying the threads were found in the zirconium group. Significant differences were also found in the quantity and the composition of bone at the bone-implant interfacial area vs. the region 1.5 mm away from the bone-implant interface, irrespective of the implant type. CONCLUSION: Zirconia implants demonstrated a lower bone remodeling activity in the periosteal region. The bone at the bone-implant interface shows a significantly lower cortical bone density, a higher trabecular density, and trabecular mineral content. Finally, zirconia and titanium implants showed similar bone-implant responses in terms of BIC and RT.

Management of Recurrent Gummy Smile After 7 Years: A Case Report.

Esthetic crown lengthening is a periodontal surgical procedure to correct excess gingival display (ie, "gummy smile"). The procedure may require soft-tissue excision only, osseous resection, or a combination of both. However, the long-term healing responses, such as soft-tissue relapse or recession and hard-tissue regrowth and resorption, have not been fully reported in the literature. This case report describes the management of a patient with esthetic concerns about a gummy smile. The patient stated that the maxillary anterior area had been previously treated with periodontal surgery 7 years earlier but the condition had slowly recurred over time. The authors highlight the possible reasons for the recurrence and the keys to successfully managing the case.

Alveolar Ridge Augmentation Around Exposed Mandibular Dental Implant With Histomorphometric Analysis.

INTRODUCTION: Alveolar ridge augmentation either before or during implant placement is a predictable procedure under certain conditions. A major complication during the healing phase is incision line opening and membrane exposure, which may result in reduced bone gain and reduced implant survival. This case report describes alveolar bone regeneration around three dental implants despite membrane exposure that developed during healing post-surgically. CASE PRESENTATION: A 72-year-old female presented requesting dental implants to replace tooth numbers 18, 19, and 20. A cone-beam computed tomography (CBCT) scan showed loss of horizontal and vertical ridge dimensions. All implants were placed with a variable degree of implant thread exposure on their buccal surfaces, ranging from 3 to 4.5 mm. Simultaneous bone grafting was performed using freeze dried bone allograft and deproteinized bovine bone mineral that was covered by a d-PTFE membrane that was secured with tacking screws. Primary closure was obtained, and flaps were sutured. Three weeks post-surgically, membrane exposure occurred. Exposure was monitored and patient was instructed to follow strict oral hygiene instructions around the exposed membrane. Membrane exposure gradually increased without infection and was removed at 16 weeks. Membrane removal revealed dense fibrous tissues covering all implant surfaces. At the second stage surgery, new bone was seen covering all the implants coronal to the cover screws. A trephine core biopsy specimen revealed significant new bone formation and connective tissue around any residual grafted bone. CONCLUSION: d-PTFE membrane exposure does not necessarily lead to adverse healing outcomes for alveolar ridge augmentation if handled properly with close patient follow-up.