Effect of dental implant therapy on the preservation of orofacial tissues: A systematic review and meta-analysis.

OBJECTIVE: Fundamentally, this review addresses the following question: In partially or fully edentulous patients, do implant-supported dental prostheses preserve orofacial tissues when compared to conventional prostheses or no therapy? MATERIALS AND METHODS: This study was conducted according to the 2020 PRISMA guidelines for systematic reviews. Electronic searches were conducted at PubMed and Embase databases followed by manual search. Clinical studies comparing the effect of implant-supported prostheses with conventional rehabilitation or no treatment on alveolar bone resorption, remaining teeth, and jaw muscle thickness were considered for inclusion. A qualitative synthesis was conducted with all included studies, and data from selected studies were pooled quantitatively to perform a meta-analysis. RESULTS: A total of 14 studies were selected for analysis. Six studies reported on the effect of implant therapy on alveolar bone resorption (n = 453), six on the remaining teeth (n = 1014), while four studies evaluated masseter muscle thickness (n = 158). The results of the meta-analyses assessing alveolar bone resorption in the posterior mandible and in the anterior area of the maxilla, both fixed and random effects models, yielded no benefit of rehabilitation with implant-supported prostheses when compared to conventional prostheses. For masseter bone thickness, however, a significant benefit for implant-supported prosthesis was observed. CONCLUSIONS: This systematic review and meta-analysis were unable to unequivocally answer the focus question. There are some indicators of the benefit of implant-supported prostheses over conventional prostheses or no therapy in preserving orofacial tissues, particularly for masseter muscle thickness. However, the evidence is still insufficient to confirm such perception.

Implant Esthetic Complications: Anatomical, Prosthetic, and Patient-Centered Considerations for Treatment.

Implant esthetic complications can negatively affect a patient's perception of implant therapy and their quality of life. This article discusses the etiology, prevalence, and strategies for the treatment of peri-implant soft tissue dehiscences/deficiencies (PSTDs). Three common scenarios of implant esthetic complications were identified and described, in which PSTDs could be managed without removing the crown (scenario I), with the surgical-prosthetic approach (crown removal; scenario II), and/or with the horizontal and vertical soft tissue augmentation and submerged healing (scenario III).

Accuracy of static computer-aided implant surgery (S-CAIS) using CAD-CAM surgical templates fabricated from different additive manufacturing technologies.

STATEMENT OF PROBLEM: Different 3D printers are available for guided implant surgery, but studies that evaluate their source of errors and their cost-effectiveness are lacking. PURPOSE: The purpose of this in vitro study was to compare the accuracy of different 3-dimensional (3D) printed surgical templates made using different additive manufacturing technologies and to evaluate the effect of implant location on the accuracy of fully guided implant placement. MATERIAL AND METHODS: Fifty partially edentulous maxillary typodonts with edentulous sites in the right second premolar (SP), right lateral incisor (LI), left central incisor (CI), and left first molar (FM) locations were scanned and printed from the standard tessellation language (STL) datasets. The study compared 5 groups for the fabrication of implant surgical templates: Varseo S-Bego (Bego), Polyjet-Stratasys (Poly), Low Force Stereolithography-FormLabs (LFS), P30+-Straumann (P30), and M2-Carbon (M2). After fully guided implant placement, the typodont was scanned, and the 3D implant positions were compared with the master model by superimposing the STL files. Descriptive statistics were calculated for groups and subgroups, and comparisons among the groups and subgroups were conducted via 2-way mixed analysis of variance, Tukey honest significant difference, and post hoc Bonferroni tests (α=.05). RESULTS: The results were site specific and not consistent within each group. For angle deviation, the within-group analysis for P30 demonstrated significantly lower values for implants positioned at site SP (1.4 ±0.8 degrees) than for sites LI (2.3 ±0.7 degrees; P=.001) and CI (2.3 ±0.8 degrees; P=.007). For 3D offset at base for implant CI, LFS was significantly higher than Bego (P=.002), Poly (P=.035), or M2 (P=.001); P30 was also significantly higher than Bego (P=.014) and M2 (P=.006). LFS had a significantly higher 3D offset at the tip than Bego (P=.001) and M2 (P=.022) for implant CI. CONCLUSIONS: The choice of 3D printer seemed to influence fully guided implant surgery in terms of the final implant position compared with initial implant planning. However, although statistically significant differences were present across groups, all additive manufacturing technologies were within clinically acceptable values.

Accuracy of Different Surgical Guide Designs for Static Computer-Assisted Implant Surgery: An In Vitro Study.

The aims of this study were to evaluate the effect of (1) the different surgical guide designs and (2) implant placement location on the accuracy of fully guided implant placement in single edentulous sites using an in vitro study model. Forty-five partially edentulous models were scanned and divided into 3 groups: group 1, tooth-supported full-arch surgical guide; group 2, 3 different tooth-supported shortened surgical guides (SSGs); and group 3, tooth-supported full-arch surgical guide with a crossbar. All surgical guides were printed and used for fully guided implant placement. A total of 180 implants (60 per group) were placed, and scan bodies were positioned on all models, and postoperative surface scan files (STL) files were obtained. Superimposition of preoperative and postoperative STL files was performed, and the accuracy of implant position was evaluated. The interaction between group and implant location was statistically significant for angle, 3D offset at the base, and at the tip (P < .001). The post-hoc tests showed a statistically significantly higher deviation for group 2 compared to group 3 for all outcomes for implants #4 (P < .05) and #7 (P < .05). There was also a statistically significant difference in all outcomes between groups 1 and 3 for implant #7 (P < .05). All surgical guide designs presented satisfactory performance with clinically acceptable levels of deviation. However, SSGs presented higher accuracy for guided implant placement in a single-edentulous site, whereas a full-arch surgical guide with a crossbar presented superior outcomes when 2 or more guided implants were placed simultaneously.

Socket healing with and without immediate implant placement.

The aim of the present review was to describe the studies produced in Latin America that contributed to the elucidation of the effect of tooth extraction with and without immediate implant installation. An electronic search was conducted in MEDLINE (PubMed), Scopus, Scielo, Lilacs, and Embase to include clinical and experimental (animal) studies on immediate implants. The studies selected had to fulfill the following inclusion criteria: (i) to present clinical and/or histological data on socket healing with or without immediate implant installation; (ii) to be approved by a Latin American Ethic Committee or comparable; and (iii) to include at least one author from a Latin American institution or to be conducted in a Latin America institution. Latin American studies that fulfilled these criteria demonstrated that immediate implant installation was conducive for predictable osseointegration and high survival rates but failed to prevent bone modeling and dimensional reduction of the alveolar ridge. In addition, it was also shown that regenerative approaches, including hard and soft tissue grafts at the time of immediate implant placement, may be beneficial to compensate for the alveolar ridge reduction. Regenerative approaches immediately after tooth extraction may decrease the amount of dimension reduction of the alveolar ridge.

Influence of the keratinized mucosa on the stability of peri-implant tissues and brushing discomfort: A 4-year follow-up study.

OBJECTIVE: The purpose of the present prospective follow-up study was to evaluate the long-term influence of the peri-implant keratinized mucosa (KM) on marginal bone level (MBL), peri-implant tissues health, and brushing discomfort. MATERIAL AND METHODS: Eighty patients were initially recruited during their maintenance visit from January to October 2013 and allocated in two groups according to KM width around implants: Wide Group (KM ≥ 2 mm) and Narrow Group (KM < 2 mm). In the four-year follow-up examination (T4), marginal bone level (MBL), modified plaque index (mPI), probing depth (PD), clinical attachment level (CAL), bleeding on probing (BoP), and brushing discomfort (BD) were reassessed and compared to the initial assessments (T0). Mann-Whitney, Wilcoxon signed-rank test, and a multilevel model were used for the statistical analysis. RESULTS: Fifty-four patients with 202 implants returned at T4. Mean mPI (0.91 ± 0.60), BoP (0.67 ± 0.21), and BD (12.28 ± 17.59) were higher in the Narrow Group than in the Wide Group (0.54 ± 0.48, 0.56 ± 0.26, and 4.25 ± 8.39, respectively). Marginal bone loss was higher in the Narrow Group (0.26 ± 0.71) than in the Wide Group (0.06 ± 0.48). Multilevel analysis suggested that KM width and time in function had a statistically significant effect on MBL. CONCLUSIONS: The findings of the present study indicate that KM width had an effect on MBL, plaque accumulation, tissue inflammation, and brushing discomfort over the studied period. Thus, the presence of a KM ≥ 2 mm around implants appears to have a protective effect on peri-implant tissues.

Standard Electrocardiographic Data from Capuchin Monkeys (Cebus apella, Linnaeus, 1758).

Capuchin monkeys are a species of arboreal primate found in all South American countries. These monkeys have been highlighted for their potential for biomedical research due to their anatomic and physiologic similarities and genetic homology with humans. Here we characterized the electrocardiographic tracings from 12 healthy, young capuchin monkeys that were restrained with ketamine and midazolam. All 12 monkeys had normal sinus rhythms. Neither P-wave duration, PR interval, QT interval, nor P- or R-wave amplitude (in millivolts) differed between males and females. The P waves were small, monophasic, and positive in all animals. The QRS complex showed positive polarity in the D1, D2, aVL, aVF, V2, V4, and V10 derivations and negative polarity in the D3, aVR, and rV2 leads. The T wave exhibited a negative polarity only in the aVR derivation in all animals in the study, and no significant difference was present between sexes. The ST segment was isoelectric in both sexes and lacked reductions and elevations. The anesthetic protocol was well tolerated all of the monkeys and allowed for diagnostic-quality acquisition, measurement, and characterization of the electrocardiogram and establishment of the normal electrocardiographic parameters of chemically restrained capuchin monkeys.

Doppler ultrasound of the placenta and maternal and fetal vessels during normal gestation in captive agoutis (Dasyprocta prymnolopha, Wagler, 1831).

The use of ultrasound for pregnancy monitoring is critical for the evaluation of hemodynamic parameters essential to fetal viability. In the present study, using B-mode and Doppler ultrasound, we characterized the placenta, subplacenta, maternal, and fetal vessels during normal gestation of healthy agoutis raised in captivity. In total, 30 agoutis were obtained from the Center for the Study and Preservation of Wild Animals, Center of Agricultural Sciences, Federal University of Piauí (Núcleo de Estudos e Preservação de Animais Silvestres-NEPAS, Centro de Ciências Agrárias-CCA, Universidade Federal do Piauí-UFPI). These animals were subjected to B-mode and Doppler ultrasound examinations to evaluate their maternal and fetal hemodynamic profiles. The placenta was located in the mesometrial region and had a discoid, ellipsoid, or globular aspect. With spectral Doppler, characteristic systolic and diastolic flow was observed in the umbilical artery. This flow increased during pregnancy. A cross-sectional view revealed a goblet-shaped placenta. The uteroplacental blood flow was characterized by a marked increase in systolic peak velocity during pregnancy, the presence of a rapid deceleration ramp, and a relatively high diastolic speed. The fetal aortic vascular flow was predominantly systolic and diastolic. The caudal vena cava blood flow was characterized by a systolic peak followed by a decreased diastolic wave throughout pregnancy. In the present study, we characterized the morphologic and hemodynamic interactions of the placenta/subplacenta with maternal and fetal vessels in agoutis at 30, 45, 60, 75, and 90 days gestation using B-mode and Doppler ultrasound. We determined the approximation and separation of the blood flow values of the umbilical artery, subplacental flow, uteroplacental artery, fetal aorta, and fetal vena cava. We believe these values may contribute to an understanding of the gestational biology and aid delivery prediction in this species.

The influence of peri-implant keratinized mucosa on brushing discomfort and peri-implant tissue health.

OBJECTIVE: The aim of this study was to compare the level of brushing discomfort (BD) during oral hygiene and peri-implant clinical variables between patients presenting implant sites with a band ≥2 mm and <2 mm of keratinized mucosa (KM). MATERIALS AND METHODS: Participating patients were recruited during routine maintenance follow-up visits from January to October 2013. Based on the presence of KM, patients were allocated into two groups: implant sites with ≥2 mm of KM (Wide Group); and implant sites with <2 mm of KM (Narrow Group). Patients were clinically assessed, and plaque index (PI), probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP) data were collected from three sites at the buccal aspect of each implant. Subsequently, patients received standardized oral hygiene instructions and cleaning devices and were asked to clean around the experimental implant sites. All patients reported on the level of BD using the visual analog scale (VAS). Non-paired Student's t-test, Wilcoxon's signed-rank test, and chi-square tests were performed to analyze the outcome variables (P < 0.05). RESULTS: Eighty patients with a total of 270 implant sites were included. Implant sites in the Narrow Group exhibited higher levels of BD (P < 0.001), PI (P = 0.0021), and BoP (P = 0.017) than implant sites in the Wide Group. CONCLUSION: Implant sites with a band of <2 mm of KM were shown to be more prone to brushing discomfort, plaque accumulation, and peri-implant soft tissue inflammation when compared to implant sites with ≥2 mm of KM.

Celiotomy by plastrotomy in a yellow-footed tortoise (geochelone denticulata)

One herein reports a successful case of celiotomy by plastrotomy for removal of foreign bodies in yellow-footed tortoise (Geochelone denticulata). The animal was treated at the Veterinary Hospital of the Federal University of Piaui, with appetite loss, regurgitation, constipation, lethargy, reluctance to walk and slightly reddish ocular mucous membranes. Radiographic examination was performed, confirming the presence of foreign bodies in the stomach. The tortoise underwent celiotomy by plastrotomy for the removal of the foreign bodies. The opening of the plastron was performed through the abdominal shields, with the aid of a circular mini grinding saw. One performed an incision in the midline between the two abdominal veins to access the abdominal cavity. A gastrotomy for removal of the foreign bodies (nails, toothpicks, stones, pieces of plastic, glass and crockery pieces) was performed after the location of the stomach. The surgery was successful and confirmed with radiographic evaluation in the immediate postoperative period. The celiotomy by plastrotomy for removal of foreign bodies in that animal proved to be a viable, very important and safe technique to the survival of chelonians.

Neste relato descreve-se um caso bem sucedido de celiotomia por plastrotomia para remoção de corpos estranhos em uma jabuti-tinga (Geochelone denticulata). O animal foi atendido no Hospital Veterinário da Universidade Federal do Piauí apresentando falta de apetite, regurgitação, constipação, letargia, relutância em andar e mucosas oculares hiperêmicas. Foi realizado exame radiográfico, o qual confirmou presença de corpos estranhos no estômago. O animal foi submetido à celiotomia por plastrotomia para remoção dos corpos estranhos. A abertura do plastrão foi realizada através dos escudos abdominais, com o auxílio de uma mini-serra circular de retífica. Foi feita uma incisão na linha média entre as duas veias abdominais para se acessar a cavidade abdominal e, uma vez exposto, o estômago foi incisado para remoção dos corpos estranhos (grampos, palitos de dente, pedras, peças de plástico, fragmentos de louças e vidros). A cirurgia foi bem sucedida e a remoção total dos corpos estranhos foi confirmada por radiografia realizada no pós-operatório imediato. A celiotomia por plastrotomia para remoção de corpos estranhos neste animal demonstrou ser uma técnica muito importante, segura e viável para a sobrevivência de quelônios.

Peri-implant soft tissue and marginal bone adaptation on implant with non-matching healing abutments: micro-CT analysis.

PURPOSE: To assess (i) the outcome of changing the horizontal-offset dimension on the peri-implant soft tissues and the crestal bone and (ii) the effect of different healing abutments (flared vs. straight) on the marginal peri-implant soft tissues and crestal bone. MATERIALS AND METHODS: Two-piece dental implants diameters of 3.5 and 4.5 mm were placed at least 1 mm subcrestal in five beagle dogs. Three different investigational groups: (i) 3.5-mm-diameter implant with narrow healing abutment (3.5N), (ii) 4.5-mm-diameter implant with narrow healing abutment (4.5N), and (iii) 3.5-mm-diameter implant with wide healing abutment (3.5W), were assessed. After 4 months of healing, the vertical distance from the marginal crestal bone (MB) to the implant shoulder (IS); the vertical distance from the IS to the first bone-to-implant contact; and the horizontal distance of bone ingrowth on the implant platform were measured with a high-resolution micro-CT (Xradia MicroXCT-200 system). RESULTS: Implants with a narrow healing caps showed an interproximal MB located between 0 and 1 mm above the implant shoulder, while the 3.5W group exhibits a mean value -0.50 mm. As all implants in group 3.5N presented a fBIC located at the level of the IS. For the 4.5N group, the mean fBIC-IS distance was -0.52 mm apically to the IS. For the 3.5WC group, the mean fBIC-IS distance was -1.42 mm. Horizontal bone apposition was only observed for the 3.5N group and the 4.5N group. CONCLUSION: The dimension of the horizontal offset would play a minimal role in reducing bone remodeling, whereas the configuration of the transmucosal component would directly influence marginal bone remodeling.

Early healing in alveolar sockets grafted with titanium granules. An experimental study in a dog model.

The aim of the present study was to evaluate the effect of the placement of titanium granules in fresh extraction sockets on early bone formation. The mesial roots of the third maxillary premolars of five adult beagle dogs were removed. On one side of the maxilla (Test group) the fresh extraction socket was grafted with titanium granules, while the contra-lateral socket was left non-grafted (Control group). After 1 month of healing, the dogs were euthanized and biopsies were obtained. The healing tissues were described, and histometric measurements were performed to obtain the percentage area occupied by connective tissue, new mineralized bone, bone marrow, and biomaterial particles. After 1 month of healing the findings from the histological examination revealed the titanium graft to be well incorporated into the provisional connective tissue or newly formed woven bone. The histometric measurements showed, however, that less mineralized bone was formed in the Test group than in the Control group. The present study suggests that the use of titanium granules in fresh extraction sockets was conducive to new bone formation. The graft of titanium granules seems, however, to delay the early phase of the healing process.