Effect of Implant Maintenance on Incidence of Peri-implantitis and Early Implant Failure: Retrospective Cohort Study.

Maintaining dental implants and managing peri-implant tissues has become integral to dental practice. Owing to the larger number of implants placed, the number of peri-implant lesions is increasing. Periodontal implant maintenance therapy (PIMT) provides a conservative long-term treatment modality to monitor and maintain implants. This study aims to investigate periodontal maintenance effects on peri-implant tissue health to add to existing evidence. A retrospective analysis included implant patients with 1-7 years of follow-up, assessing peri-implantitis and early implant failure as outcome variables. The frequency of PIMT, implant characteristics, and demographics served as predictors, and associations between peri-implantitis, implant failure, and PIMT frequency were analyzed using Fisher exact tests with the significance level set at .05. Data were collected on 501 implants from 185 patients. Twenty-nine (6%) demonstrated peri-implantitis, whereas 22 (5%) experienced early implant failure. A significant association between PIMT and peri-implantitis was observed (p-value = .0169) with the rate of peri-implantitis at 9% (n = 20) for patients without PIMT and only 4% (n = 10) for those with PIMT. Whereas PIMT was not significantly associated with early implant failure (p-value = .4372), peri-implantitis was: 25% of implants with peri-implantitis experienced early failure compared with 4% without (p-value = .0062). Considering the limitations of the present study, the absence of PIMT was found to be associated with peri-implantitis, which was itself associated with early implant failure. Implant maintenance at 6-month intervals is important in maintaining peri-implant health.

Accuracy of Implant Placement Position Using Nondental Open-Source Software: An In Vitro Study.

PURPOSE: To evaluate the accuracy of implant placement position using two different dental implant planning software. MATERIALS AND METHODS: A set of Digital Imaging and Communications in Medicine (DICOM) files from a cone beam computed tomography of a patient missing maxillary right first premolar was used. Implant planning was done using two open-source programs: A nondental 3D Slicer/Blender (3DSB) software and a commercial dental implant treatment planning program: Blue Sky Plan 4 (BSP4). An intraoral scan of the same patient was used to create a standard tessellation language (STL) file of the maxillary arch and later printed into 20 identical casts. Ten surgical guides were printed for each group as well. A dental implant (3.8 mm × 12 mm, Biohorizons) was placed into each cast using fully guided surgical protocol. The horizontal displacements at the implant cervical platform and at the implant apex as well as the angulation displacements were measured using digital scanning of the implant scan bodies and were analyzed using a 3D compare software. Statistical analyses were conducted (⍺ = 0.05) using t-test and F-test to examine differences in trueness and precision, respectively. RESULTS: The average horizontal deviations for the platform and the apex, respectively, were 0.33 ± 0.12 mm and 0.76 ± 0.30 mm for 3DSB and 0.44 ± 0.21 mm and 0.98 ± 0.48 mm for BSP4. The average angulation deviations for 3DSB and BSB4 were 2.34 ± 0.93° and 3.07 ± 1.57°, respectively. There were no statistical differences in the means (t-test) of the platform, apex, and angulation deviations (p = 0.16, p = 0.19, and p = 0.18, respectively). There were statistical differences in the variances (F test) of the platform (p = 0.043) and angulation (p = 0.049) deviations but not the apex (p = 0.059) deviations. CONCLUSIONS: The combination of nondental open-source software, 3D Slicer/Blender can be used to plan implant guided surgery with an accuracy similar to commercial dental software with slightly higher precision. Open-source nondental software can be considered as an alternative in dental implant treatment planning and guided surgery.

Virginia-based periodontists' perceptions: Current and future trends of the specialty.

BACKGROUND: The aim of this survey was threefold: (1) describe the demographics of periodontists and their practices in Virginia; (2) explore periodontists' perceptions of the impact that changes in the field of dentistry (i.e. increasing corporate dentistry, graduate debt, digitalization, and volume of periodontal procedures done by general practitioners [GPs]) are having on the specialty; (3) explore how periodontists might adjust their practices to account for these trends. METHODS: An electronic survey was emailed to Virginia-based American Academy of Periodontology (AAP) members assessing personal and practice demographics, trends in treatment modalities and practice models, and to survey how periodontists plan to adapt their practices for these trends. Virginia has large urban, suburban and rural municipalities, which renders the state a favorable representation of the United States as a whole. RESULTS: The response rate was 31% (n = 46). Most respondents (87%) were male and practiced full-time (70%). Respondents reported practicing predominantly in urban (n = 19, 41%) and suburban (n = 24, 52%) and less in rural areas (n = 3, 7%). In current practice, respondents reported greater numbers of referrals from more experienced GPs. Student debt after periodontal residency was significantly associated with age (P value = 0.0002), with 56% of respondents aged <40 years reporting student loans >$250,000 compared with 3% for those aged ≥40 years. Respondents ranked biologic advances, treatment of peri-implantitis, advances in digital dentistry, development of corporate and group practice models, and integration of more periodontal services in GP practices as the most likely trends to impact periodontal practices. The most commonly reported practice adjustments included expansion of existing services, increasing the number of periodontists in the practice, and joining with other specialists or GPs to create group practices. CONCLUSION: Periodontists perceive the need to expand services, increase the number of providers in their practices or create group practices to account for increased corporate dentistry, graduate debt, digitalization, and volume of periodontal procedures performed by GPs.

Alveolar Ridge Expansion by Osseodensification-Mediated Plastic Deformation and Compaction Autografting: A Multicenter Retrospective Study.

INTRODUCTION: Osseodensification preserves bone bulk, facilitates compaction autografting, and deforms trabecular bone in an outward strain, which result in alveolar ridge plastic expansion. The aim of this retrospective study was to evaluate ridge expansion after osseodensification. MATERIALS AND METHODS: Patients treated with implant placement through osseodensification were evaluated. The alveolar ridge width was measured at the level of the crest and 10 mm apical to the crest before and after osseodensification. Insertion torque and implant stability quotient (ISQ) values were recorded at implant placements. Expansion values were grouped into the following 3 groups according to the initial alveolar ridge width: group 1: 3 to 4 mm (n = 9), group 2: 5 to 6 mm (n = 12), and group 3: 7 to 8 mm (n = 7). RESULTS: Twenty-one patients who received 28 implants were included. Twenty-six implants were integrated, resulting in a survival rate of 92.8%. There was a significant difference in the mean expansion value at the coronal aspect of the ridge between group 1, group 2, and group 3 (2.83 ± 0.66 mm, 1.5 ± 0.97 mm, 1.14 ± 0.89 mm, P < 0.05). The mean torque and ISQ values were 61.2 ± 13.9 Ncm and 77 ± 3.74. CONCLUSION: Osseodensification can alter ridge dimensions and allow for ridge expansion. Greater expansion can be expected at the crest in narrow ridges with adequate trabecular bone volume.

Thermocouple Probe Orientation Affects Prescribed Fire Behavior Estimation.

Understanding the relationship between fire intensity and fuel mass is essential information for scientists and forest managers seeking to manage forests using prescribed fires. Peak burning temperature, duration of heating, and area under the temperature profile are fire behavior metrics obtained from thermocouple-datalogger assemblies used to characterize prescribed burns. Despite their recurrent usage in prescribed burn studies, there is no simple protocol established to guide the orientation of thermocouple installation. Our results from dormant and growing season burns in coastal longleaf pine ( Mill.) forests in South Carolina suggest that thermocouples located horizontally at the litter-soil interface record significantly higher estimates of peak burning temperature, duration of heating, and area under the temperature profile than thermocouples extending 28 cm vertically above the litter-soil interface ( < 0.01). Surprisingly, vertical and horizontal estimates of these measures did not show strong correlation with one another ( ≤ 0.14). The horizontal duration of heating values were greater in growing season burns than in dormant season burns ( < 0.01), but the vertical values did not indicate this difference ( = 0.52). Field measures of fuel mass and depth before and after fire showed promise as significant predictive variables ( ≤ 0.05) for the fire behavior metrics. However, all correlation coefficients were less than or equal to = 0.41. Given these findings, we encourage scientists, researchers, and managers to carefully consider thermocouple orientation when investigating fire behavior metrics, as orientation may affect estimates of fire intensity and the distinction of fire treatment effects, particularly in forests with litter-dominated surface fuels.

Dental patients' self-reported use of dietary supplements on medical history questionnaires.

Dietary supplement effects and drug interactions can lead to significant adverse health events, thus potentially impacting the safe delivery of oral healthcare. This study sought to determine the frequency of, and factors impacting, dietary supplement use among 209 dental patients and whether the design of a medical history questionnaire influences reporting of supplement use. Patients were randomly allocated to 1 of 2 groups in which they completed either a standard medical history questionnaire (n = 107) or the same questionnaire with an additional item about dietary supplement use (n = 102). All patients were then administered a survey with questions about their demographics, their use and knowledge of dietary supplements, and the person or persons who recommended dietary supplement use to the patient. While 62% of the total population (130/209) reported supplement use, specific prompting nearly doubled the number of supplements reported (mean with prompting: 1.53; mean without prompting: 0.76; P < 0.0001). Patients younger than 30 years of age reported significantly less dietary supplement use than all other age groups except the 30-40 age group (P = 0.0003). An estimated 70% of all respondents were not aware of potentially detrimental side effects of dietary supplement use or possible interactions with conventional drug therapies. Since patients tended to report a greater use of dietary supplements when specifically asked about their use on a medical history questionnaire, a checklist or set of designated questions may be a suitable first step toward gathering this essential information.

Aquacultured rainbow trout (Oncorhynchus mykiss) possess a large core intestinal microbiota that is resistant to variation in diet and rearing density.

As global aquaculture fish production continues to expand, an improved understanding of how environmental factors interact in fish health and production is needed. Significant advances have been made toward economical alternatives to costly fishmeal-based diets, such as grain-based formulations, and toward defining the effect of rearing density on fish health and production. Little research, however, has examined the effects of fishmeal- and grain-based diets in combination with alterations in rearing density. Moreover, it is unknown whether interactions between rearing density and diet impact the composition of the fish intestinal microbiota, which might in turn impact fish health and production. We fed aquacultured adult rainbow trout (Oncorhynchus mykiss) fishmeal- or grain-based diets, reared them under high- or low-density conditions for 10 months in a single aquaculture facility, and evaluated individual fish growth, production, fin indices, and intestinal microbiota composition using 16S rRNA gene sequencing. We found that the intestinal microbiotas were dominated by a shared core microbiota consisting of 52 bacterial lineages observed across all individuals, diets, and rearing densities. Variations in diet and rearing density resulted in only minor changes in intestinal microbiota composition despite significant effects of these variables on fish growth, performance, fillet quality, and welfare. Significant interactions between diet and rearing density were observed only in evaluations of fin indices and the relative abundance of the bacterial genus Staphylococcus. These results demonstrate that aquacultured rainbow trout can achieve remarkable consistency in intestinal microbiota composition and suggest the possibility of developing novel aquaculture strategies without overtly altering intestinal microbiota composition.

The effect of esthetic crown lengthening on perceptions of a patient's attractiveness, friendliness, trustworthiness, intelligence, and self-confidence.

BACKGROUND: Smile esthetics have been shown to play a major role in the perception of whether a person is attractive, and whether they are perceived as friendly, trustworthy, intelligent, and self-confident. A proposed major determinant of the esthetics of a smile is the amount of gingival display, which can be excessive in cases of altered passive eruption. The aim of this study is to see whether altering the amount of gingival display of patients would affect dental professionals' and laypersons' perceptions of the aforementioned social parameters. METHODS: Patients were identified as having altered passive eruption and excessive gingival display. Smiling "control" photographs were taken and then digitally altered so as to lengthen the teeth and thus reduce the amount of gingival display. These became the "test" photographs. The control and test photographs were shown in random order. The control group of evaluators consisted of senior dental students, and the test group of evaluators comprised students who had no formal dental training. Groups were asked to rate, on a visual analog scale, each picture's attractiveness, friendliness, trustworthiness, intelligence, and self-confidence. RESULTS: The test pictures with less gingival display were consistently and statistically significantly rated higher for all five social parameters than were their control counterparts (P <0.0001). When analyzed as an isolated effect, there were no statistically significant differences between the control group and the test group of evaluators when rating the pictures. Pictures depicting African Americans were judged to be more trustworthy (P = 0.0467) and self-confident (P = 0.0490) than pictures depicting white individuals. Pictures depicting women were judged to be more trustworthy (P = 0.0159) and intelligent (P = 0.0329) than pictures depicting men. All the social parameters were positively and statistically significantly correlated with each other (P <0.0001). CONCLUSIONS: Excessive gingival display did negatively affect how attractive a person's smile is judged to be. In addition, how friendly, trustworthy, intelligent, and self-confident a person was perceived to be was inversely related to the amount of gingival display. Untrained laypeople were just as sensitive to these differences as senior dental students.

Randomized, prospective, clinical evaluation of prosthodontic modalities for mandibular implant overdenture treatment.

STATEMENT OF PROBLEM: Mandibular implant overdentures provide improved treatment outcome than conventional denture therapy, but there is controversy as to which overdenture treatment is the best choice. PURPOSE: This study evaluated 3 different mandibular implant overdenture treatments with respect to prosthesis retention and stability, tissue response, patient satisfaction and preference, and complications to determine treatment outcomes. MATERIAL AND METHODS: In a prospective, randomized clinical trial, using a crossover design, 30 subjects (mean age, 58.9; 63% male) received 4 implants in the anterior mandible. For each subject, 3 different overdenture attachment types were fabricated and/or fitted to the implants. These included a 4-implant bar attachment fitted to all 4 implants, a 2-implant bar attachment, and 2 independent ball attachments. Subjects were randomly assigned to 1 of 6 possible treatment sequences and received all 3 attachment types each for approximately 1 year. Data were collected at baseline, and at 6 and 12 months for treatment types. Denture retention and stability and parameters of soft tissue response were recorded. Complications were documented and questionnaires were used to identify subject masticatory ability, denture complaints, and preferences. Data were analyzed to determine statistical equivalence among the 3 different treatments using the Schuirmann's two one-sided test (TOST) procedure, and the Wilcoxon-Mann-Whitney TOST procedure (α=.05). RESULTS: Force gauge prosthesis retention measurements showed that the 3 treatment types were not statistically equivalent, with the 4-implant bar demonstrating the greatest retention. Criterion-based retention scores were statistically equivalent for all treatments. Both the force gauge and criterion-based prosthesis stability measurements were statistically equivalent among all 3 treatment types. Analysis of all other multiple criterion-based scoring systems indicated the majority of these variables demonstrated equivalence. Where equivalence was not identified, the most favorable responses were typically found with the O-ring treatment, and the least favorable with the 4-implant bar treatment. From the small percentage of treatment visits demonstrating minor complications, no single treatment presented with greater complications than the others. For the treatment preference among subjects, 52% selected the independent ball attachment, 32% the 4-implant bar, and 16% the 2-implant bar (P=.10). CONCLUSIONS: The 2-implant independent treatment used in this study provided equivalent or more favorable treatment outcomes for most measured parameters relative to the more complex and costly 2- and 4-implant bar attachments. The 4-implant bar treatment provided greater prosthesis retention than the other treatment types in this study, but after experience with all systems, subjects were more satisfied with and preferred the independent implant treatment.

The National Fire and Fire Surrogate study: effects of fuel reduction methods on forest vegetation structure and fuels.

Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an information-theoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wildfire damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass). In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed fire treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment.

Reducing airborne ectomycorrhizal fungi and growing non-mycorrhizal loblolly pine (Pinus taeda L.) seedlings in a greenhouse.

Atmospheric spores of ectomycorrhizal (ECM) fungi are a potential source of contamination when mycorrhizal studies are performed in the greenhouse, and techniques for minimizing such contamination have rarely been tested. We grew loblolly pine (Pinus taeda L.) from seed in a greenhouse and inside a high-efficiency particulate air-filtered chamber (HFC) constructed within the same greenhouse. Seedlings were germinated in seven different sand- or soil-based and artificially based growth media. Seedlings grown in the HFC had fewer mycorrhizal short roots than those grown in the open greenhouse atmosphere. Furthermore, the proportion of seedlings from the HFC that were completely non-mycorrhizal was higher than that of seedlings from the greenhouse atmosphere. Seedlings grown in sterilized, artificially based growth media (>50% peat moss, vermiculite, and/or perlite by volume) had fewer mycorrhizal short roots than those grown in sand- or soil-based media. The HFC described here can minimize undesirable ECM colonization of host seedlings in greenhouse bioassays. In addition, the number of non-mycorrhizal seedlings can be maximized when the HFC is used in combination with artificially based growth media.

Clinical crown length of the maxillary anterior teeth preorthodontics and postorthodontics.

BACKGROUND: Prevalence information on excessive gingival display in postorthodontic patients is limited. By studying the size relationship of the clinical crowns of teeth, in an orthodontic population, we can begin to quantify their need for periodontal plastic surgery. METHODS: Preorthodontic and postorthodontic crown dimensions were measured on 200 plaster models, and after 5 years, 31 of the subjects were recalled to repeat the measurements in a clinical examination. The measurements included clinical crown lengths and widths of the six anterior teeth, and these values were compared to known ideals. RESULTS: This study revealed a significant increase in the length of the maxillary anterior crowns over the three examinations, yet these values were still approximately 1.5 mm shorter than ideal. The mean crown width-to-length ratio was 87% to 88% for maxillary central incisors, clearly above the accepted "ideal." In addition, 61% to 71% of maxillary central incisors exceeded allowable crown width-to-length ratios, and 61% of subjects displayed asymmetry in gingival architecture. CONCLUSIONS: Although this study only examined one aspect of excessive gingival display, to our knowledge it is the first study to show that in a predominantly young, postorthodontic population, the prevalence of non-ideal width-to-length ratios is >65% and the presence of asymmetry is >60%. Therefore, close interaction between the periodontist and the orthodontist is necessary to diagnose these conditions to provide patients with all options for improving their smile.

Surgical crown lengthening: evaluation of the biological width.

BACKGROUND: Previous surgical crown lengthening studies have investigated positional changes of the free gingival margin but not the biological width. Histological studies utilizing animal models have shown that postoperative crestal resorption allowed reestablishment of the biological width. However, very little work has been done in humans. Therefore, the purpose of this study was to evaluate the positional changes of the periodontal tissues, particularly the biological width, following surgical crown lengthening in human subjects. METHODS: Twenty-three (23) patients who needed surgical crown lengthening to gain retention necessary for prosthetic treatment and/or to access caries, tooth fracture, or previous prosthetic margins entered the study. The following parameters were obtained from line angles of treated teeth (teeth requiring surgical crown lengthening) and adjacent teeth with adjacent and non-adjacent sites: plaque and gingival indexes, free gingival margin, probing depth, attachment level, bone level, direct bone level, and biological width. During surgery, the bone level was reduced based on the future prosthetic margin and predetermined biological width; flaps were placed at the bony crest. Patients were examined at baseline and at 3 and 6 months postoperatively. RESULTS: Eighteen patients completed the study. Overall, the amount of bone resected was 1 to 5 mm. At 90% of treated sites, > or = 3 mm of bone was removed. At 3 months, the apical displacement of the free gingival margin at non-adjacent, adjacent, and treated sites was 2.46 +/- 0.25 mm, 2.68 +/- 0.20 mm, and 3.07 +/- 0.16 mm, respectively. There was no significant change in the position of the free gingival margin from 3 to 6 months. The biological width at all sites was smaller at 3 and 6 months compared to baseline (P<0.05) except for the treated sites, which were not significantly different from baseline at 6 months. CONCLUSIONS: During surgical crown lengthening, the bone level was lowered for placement of the prosthetic margin and reestablishment of the biological width. The biological width, at treated sites, was reestablished to its original vertical dimension by 6 months. In addition, a consistent 3 mm gain of coronal tooth structure was observed at the 3- and 6-month examinations.

Effects of water temperature and substrate type on spore production and release in eastern Tubifex tubifex worms infected with Myxobolus cerebralis.

Eastern Tubifex tubifex worms were exposed to Myxobolus cerebralis spores at 9, 13, 17, and 20 C in 1-L jars that contained sand, mud, or leaf litter as substrata. Beginning 60 days after exposure, water from each jar was filtered daily and examined for the presence of waterborne triactinomyxon spores (TAMs). On discovering a single TAM from an experimental jar, 48 T. tubifex worms from that jar were placed individually into 24-well plates. Spores released from individual infected T. tubifex worms were quantified to determine the first day of TAM release from infected worms, the infection rate, the total number of TAMs released per worm, and the duration of release. No TAMs were found in any of the jars incubated at 20 C or in uninfected, control worms at any temperature. The total number of TAMs released by infected worms in mud and sand was highest at 13 C compared with other temperatures. Infection rates among individual worms increased with temperature between 9 and 17 C. Higher temperatures (up to 17 C) induced earlier TAM releases among infected worms, and substratum did not influence this production parameter. The average duration of TAM release decreased as the temperature increased from 9 to 17 C, and there was a significant effect of substratum in the groups maintained at 13 and 17 C. In all temperature treatments between 9 and 17 C, the duration of release was least in the worms maintained in leaf litter, as was the total number of TAMs released during the experimental period and the median number of TAMs per production day.