Accuracy of dynamic implant navigation surgery performed by a novice operator.

AIM: The main objective was to evaluate the accuracy of dynamic navigation-guided surgery (DNGS) for implant positioning performed by a novice operator. The secondary objectives were to analyze the operator's learning curve and identify possible complications deriving from the technique. MATERIALS AND METHODS: Twenty-five implants were placed in eight partially edentulous human heads. Preoperative CBCT scans were imported to planning software to determine the implant positions. Implants were placed using a dynamic navigation system. Postoperative CBCTs were superimposed onto the implant planning images. Discrepancies between the virtually planned implant positions and the postoperative positions were evaluated by measuring horizontal platform deviation, apex deviation, apicocoronal (vertical) deviation, and angular deviation. RESULTS: Mean platform, apex, vertical, and angle deviations were 1.55 ± 0.81 mm, 2.45 ± 0.84 mm, 1.59 ± 0.70 mm, and 5.56 ± 4.03 degrees, respectively. No significant differences were found between the maxilla and mandible or between anterior and posterior sites. A flat learning curve was observed, with the exception of the implant platform, where a tendency toward improvement in accuracy was observed between the 8th and the 17th implant placed. No complications were reported. CONCLUSIONS: Based on the results of a study performed by a novice operator on a cadaveric model, DNGS allows accurate implant placement within a 2-mm safety margin in terms of implant platform and vertical positions, and a 3-mm margin in apical vicinities. The technique requires practice to learn the required eye-hand coordination. (Int J Comput Dent 2022;25(4):377-0; doi: 10.3290/j.ijcd.b2588207).

Correction to: Influence of surface treatment on osseointegration of dental implants: histological, histomorphometric and radiological analysis in vivo.

Dear Professor Dr. Matthias Hannig. Editor-in-Chief Clinical Oral Investigations. Following the publication of our paper by Calvo Guirado et al, 2015 [1] in Clinical Oral Investigations, it came to light that a certain part of the text at the materials and methods and results sections were similar.

Zirconia with laser-modified microgrooved surface vs. titanium implants covered with melatonin stimulates bone formation. Experimental study in tibia rabbits.

OBJECTIVES: The aim of the study was to evaluate if zirconia implants with micro-grooved surfaces supplemented with melatonin enhance the bone-to-implant contact (BIC) vs. titanium implants with the same coating. MATERIALS AND METHODS: Eighty implants divided in four groups were inserted in the tibia of 20 New Zealand rabbits as follows: (group A) 20 titanium implants; (group B) 20 micro-grooved zirconia implants; (group C) 20 titanium implants supplemented with melatonin and (group D) 20 micro-grooved zirconia implants supplemented with melatonin. Histometric and SEM evaluation of BIC were evaluated after 1 and 4 weeks. RESULTS: At 1 week, group C (29.7 ± 2.4%) and group D (28.9 ± 1.3%) implants showed higher BIC% compared with group A and B (P < 0.05). After 4 weeks, group D showed higher BIC compared with all the groups (47.5 ± 2.2%) (P < 0.05). Also Connective tissue was higher in groups B (78.9 ± 2.1%) and D (88.7 ± 1.2%) related to titanium and zirconia melatonin untreated at 4 weeks (P < 0.05). CONCLUSIONS: Within the limitations of this pilot study in rabbits, we can conclude that the local application of melatonin increases the BIC values in titanium and in zirconia implants at 1 week.

Influence of surface treatment on osseointegration of dental implants: histological, histomorphometric and radiological analysis in vivo.

OBJECTIVE: The aim of this article is to compare the influence of surface treatment on the integration (at 2, 4 and 8 weeks) of 120 dental implants inserted in 60 tibiae of rabbits. MATERIALS AND METHODS: Four different surfaces were double-blind tested: blasted, acid-etched and discrete crystal deposition (DCD) (group A); blasted (group B); acid-etched (group C) and blasted and acid-etched (group D). Bone-to-implant contact plus reverse torque and bone level were measured at the time of implant insertion and at 14, 28 and 56 days of healing. RESULTS: Group A showed the highest early and late bone-to-implant contact (BIC) values: 40.8 ± 2.3 % at 14 days decreasing to 27.7 ± 1.1 % after 28 days and 39.4 ± 1.4 % at 56 days. For group B, the average BIC values at 14, 28 and 56 days were 23.34 ± 2.1, 23.77 ± 1.9 and 29.47 ± 1.7 %, respectively. Group C showed a value of 25.72 ± 2.3 % after 14 days of integration, 34.92 ± 2.2 % at 28 days and 32.91 ± 1.6 % at 56 days. Group D showed a BIC value of 32 ± 2.5 % at 14 days, 32.85 ± 1.4 % at 28 days and 34.04 ± 2.3 % at 56 days. In the scanning electron microscopy (SEM) analysis, no statistically significant differences were found. The Ca/P ratio values were 1.762 for surface A, 1.625 for surface B, 1.663 for surface C and finally 1.722 for surface D. CONCLUSIONS: Therefore, we conclude that even if there seems to be a tendency to obtain better BIC results with surface A (blasted-etched and covered with hydroxyapatite (HA)), no statistical differences were obtained in this study. CLINICAL RELEVANCE: The study shows the influence of different implant surfaces in increasing osseointegation for immediate loading implants.

COVID-19 pandemic and its impact on dental students: A multi-institutional survey.

PURPOSE/OBJECTIVES: To investigate dental students' perceptions and concerns regarding the COVID-19 pandemic, their coping strategies and support resources, and their perceived stress levels. METHODS: A customized 19-item survey and the perceived stress scale (PSS) were applied to undergraduate dental students from the US, Spain, Ireland, Chile, India, and Brazil between April 10 and July 5, 2020. Linear modeling and mediation analysis were used to explore the relationships among demographics, stressors, coping mechanisms, social support, and stress RESULTS: A total of 4475 students responded to the survey. The majority (72.4%) were women, and 52.3% had no COVID-19 training at the time of the survey. The students reported that they had to accommodate to changes in patient care (96.6%) and didactic learning (95.2%) activities, while 88.5% of the respondents indicated at least one of their courses moved online. Transition to online courses went "smoothly with some troubles" for 51.8% of the respondents, and 48.3% perceived the faculty as prepared for the online transition; however, 45.9% reported feeling extremely concerned about the impact of COVID-19 on their education. The average PSS score was 21.9 of 40 (moderate stress). Multivariate models were built for participants with full data (n = 3899). Being male, having completed more dental coursework, and perceiving a smoother transition were associated with lower PSS scores; more concern about academic progress was associated with higher PSS. Faculty support mediated the relationship between a smoothness of transition and concern about academic progress and PSS scores CONCLUSION: Stress caused by the pandemic may be alleviated by smoother transition and good faculty support.

Fully Guided Tooth Autotransplantation Using a Multidrilling Axis Surgical Stent: Proof of Concept.

INTRODUCTION: Digital technology has been progressively introduced into tooth autotransplantation to enhance both treatment planning and surgery. The aim of this report was to describe a novel protocol for fully guided tooth autotransplantation. METHODS: This report includes 10 consecutive patients treated with a complete virtual planning and a multidrilling axis surgical guide in combination with the computer-aided rapid prototyping model. RESULTS: All transplanted teeth fulfilled the criteria for success over a mean follow-up duration of 13.1 months. No signs of progressive root resorption or pain were found during follow-up. One case required minimal adjustment of the surgical stent to allow correct seating, whereas a second case could not be performed fully guided because of limited mouth opening. CONCLUSIONS: Our protocol for fully guided tooth autotransplantation is a viable option that involves minimal bone preparation in a short surgical time. Future research should focus on further investigation of the benefits of this novel protocol in a larger sample.

Comparison of Three Biphasic Calcium Phosphate Block Substitutes: A Histologic and Histomorphometric Analysis in the Dog Mandible.

The purpose of this animal study was to determine which ratio of hydroxyapatite (HA) and tricalcium phosphate (TCP) is the most appropriate in the composition of alloplastic biphasic block grafts, in terms of bone density and bone formation, for the regeneration of alveolar defects. Different concentrations of HA/TCP were used for the alloplastic block grafts: 100/0 (HA100 group), 79/21 (HA75 group), and 57/43 (HA50 group); the control treatment filled the defect with a collagen plug. All control and test sites were covered with a resorbable collagen membrane. Sacrifices were performed at 4, 12, and 24 weeks after grafting. Microcomputed tomography and histologic and histomorphometric analyses were performed to determine bone density and the characteristics of the regenerated bone as well as the percentages of newly formed bone (NB), residual material (RM), and connective tissue (CT). Bone density increased significantly over time (P < .001), with stabilization between 12 and 24 weeks (P = 1.000). No differences in density were observed between the different test blocks (P = .813). The percentage of NB increases over time, independent of the concentration (P < .001). At 12 weeks, the control group exhibited more NB than the HA100 group (P < .001). At 24 weeks, the HA50 group exhibited more NB than the HA100 (P < .001) and control (P = .066) groups. At 24 weeks, the HA100 and HA75 groups showed high RM percentages. The HA50 group exhibited an increased tendency of less RM percentage compared with the HA100 and HA75 groups. Although slight differences were found, the HA50 group's HA/TCP ratio seems the appropriate concentration when taking into account the bone density and percentage of NB and RM at 12 and 24 weeks of healing.

Endosseous dental implant fractures: an analysis of 21 cases.

Implant fracture is an infrequent cause of implant failure. The present study evaluates 21 fractured implants, with an analysis of patient age and sex, the type, length and diameter of the implant, positioning in the dental arch, the type of prosthetic rehabilitation involved, the number of abutments and pontics, the presence or absence of distal extensions or cantilevers, and loading time to fracture. Implant fracture was more common in males than in females (15:4), and the mean patient age was 56.9 years. Most cases (n = 19) corresponded to implant-supported fixed prostheses - 16 with cantilevers of different lengths - while only two fractured implants were supporting overdentures instead of fixed prostheses. The great majority of fractured implants (80.9%) were located in the molar and premolar regions, and most fractured within 3-4 years after loading. It is important to know and apply the measures required to prevent implant fracture, and to seek the best individualized solution for each case - though complete implant removal is usually the treatment of choice.

Do Penicillin-Allergic Patients Present a Higher Rate of Implant Failure?

PURPOSE: The aim of this clinical study was to determinate if patients allergic to penicillin present a higher incidence of dental implant failure compared with nonallergic patients. MATERIALS AND METHODS: This cross-sectional clinical study analyzed patients rehabilitated with endosseous dental implants between September 2011 and July 2015, at the University Dental Clinic, School of Dentistry, International University of Catalonia (UIC). Prophylactic antibiotic therapy was prescribed for all patients: a single dose of 2 g of amoxicillin taken orally 1 hour before implant surgery for non-penicillin-allergic patients, and 600 mg of clindamycin taken orally 1 hour before the implant surgery for penicillin-allergic patients. Postsurgical antibiotics were prescribed to prevent early implant failures and postoperative infections: amoxicillin 750 mg three times a day for 7 days for nonallergic patients, and in patients with penicillin allergy, 300 mg clindamycin every 6 hours for 7 days. Implant failure was defined as the removal of the implant for any reason and was classified as early or late failure. RESULTS: A total of 1,210 patients' files were analyzed; 8.03% of nonallergic patients and 24.68% of penicillin-allergic patients presented at least one implant failure. In penicillin-allergic patients, 21.05% were classified as late implant failure and 78.95% as early implant failure, with a lack of osseointegration (80%) being the mean reason for an early implant failure. Penicillin-allergic patients demonstrated a higher risk of implant failure with a risk ratio of 3.84 (95% CI) compared with nonallergic patients. CONCLUSION: Penicillin-allergic patients treated with clindamycin presented almost four times the risk of suffering dental implant failure, although other variables such as implant brand, location, and the surgeon's skill might have influenced these results.

Scanning electron microscopy study of new bone formation following small and large defects preserved with xenografts supplemented with pamidronate-A pilot study in Fox-Hound dogs at 4 and 8 weeks.

The aim of the present study was to evaluate the feasibility of SEM and EDX microanalysis on evaluating the effect of porcine xenografts (MP3®) supplemented with pamidronate during socket healing. Mandibular second premolars (P2) and first molars (M1) were extracted from six Beagle dogs. P2 were categorized as small defects (SD) and M1 as large defects (LD). Four random groups were created: SC (small control defects with MP3®), ST (small test defects MP3®+pamidronate), LC (large control defects with MP3®), and LT (large test defects MP3®+pamidronate). At four and eight weeks of healing the samples were evaluated fisically through scanning electron microscopy (SEM), and chemical element mapping was carried out by Energy dispersive X-ray spectroscopy (EDX). After four weeks of healing, SEM and EDX analysis revealed more mineralized bone in ST and LT groups compared with control groups (p<0.05). After eight weeks, Ca/P ratios were slightly higher for small defects (groups SC and ST); in SEM description, in both control and test groups, trabecular bone density was similar to the adjacent mineralized cortical bone. Within the limitations of this experimental study, SEM description and EDX elemental microanalysis have demonstrated to be useful techniques to assess bone remodelling of small and large defects. Both techniques show increased bone formation in test groups (MP3® modified with pamidronate) after four and eight weeks of healing.

Volumetric changes in alveolar ridge preservation with a compromised buccal wall: a systematic review and meta-analysis

BACKGROUND: Many studies have addressed socket preservation, though fewer publications considering buccal wall loss can be found, since the literature typically considers sockets with four walls. A systematic review was made on the influence of type II buccal bone defects, according to Elian's Classification, in socket grafting materials upon volumetric changes in width and height. MATERIAL AND METHODS: An electronic and manual literature search was conducted in accordance to PRISMA statement. The search strategy was restricted to randomized controlled trials (RCTs) and controlled clinical trials (CCTs) describing post-extraction sockets with loss of buccal wall in which alveolar ridge preservation (ARP) was carried out in the test group and spontaneous healing of the socket (SH) was considered in the control group. RESULTS: The search strategy yielded 7 studies. The meta-analysis showed an additional bone loss of 2.37 mm in width (p > 0.001) and of 1.10 mm in height (p > 0.001) in the absence of ARP. The reconstruction of the vestibular wall was not evaluated in any study. The results also showed moderate to great heterogeneity among the included studies in terms of the changes in width and height. CONCLUSIONS: Despite the heterogeneity of the included studies, the results indicate a benefit of ARP versus SH. Further studies are needed to determine the volumetric changes that occur when performing ARP in the presence of a buccal bone wall defect

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Endosseous dental implant fractures an analysis of 21 cases

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Implant fracture is an infrequent cause of implant failure. The present study evaluates 21 fractured implants, with an analysis of patient age and sex, the type, length and diameter of the implant, positioning in the dental arch, the type of prosthetic rehabilitation involved, the number of abutments and pontics, the presence or absence of distal extensions or cantilevers, and loading time to fracture.Implant fracture was more common in males than in females (15:4), and the mean patient age was 56.9 years. Most cases (n = 19) corresponded to implant-supported fixed prostheses - 16 with cantilevers of different lengths – while only two fractured implants were supporting overdentures instead of fixed prostheses. The great majority of fractured implants (80.9%) were located in the molar and premolar regions, and most fractured within 3-4 years after loading.It is important to know and apply the measures required to prevent implant fracture, and to seek the best individualized solution for each case - though complete implant removal is usually the treatment of choice

Tratamiento quirúrgico de la queilitis actínica / Surgical management of actinic cheilitis

Objetivo: Analizar los factores etiológicos que pueden influir en el desencadenamiento de la enfermedad y los resultados obtenidos después del tratamiento quirúrgico de una serie de pacientes. Diseño del estudio: En una muestra de 54 pacientes que presentaban queilitis actínica se valoraron la historia clínica, los posibles factores desencadenantes, el patrón histológico y la recurrencia de las lesiones. Cuarenta y un casos fueron tratados mediante bermellectomía con bisturí de hoja fría seguida del cierre primario del defecto con un colgajo de la mucosa bucal. En los 13 casos restantes se efectuó la bermellectomía con el láser de C02.Resultados: En el análisis de los antecedentes de los pacientes se observó que el 35,2 por ciento presentaban patología hepática asociada al consumo de alcohol y que el 77,8 por ciento eran fumadores. Por último, con relación a la exposición solar el 53,1 por ciento de los hombres tenían profesiones al aire libre y el 100 por ciento de las mujeres presentaban exposiciones solares importantes. La clínica más frecuente fue el sangrado y la presencia de placas leucoplásicas, mientras que solamente el 16 por ciento presentaba dolor. Más del 40 por ciento de los pacientes estaban asintomáticos. Después del tratamiento, y tras un período de control mínimo de 6 meses, el 90,74 por ciento de los pacientes presentaron una curación total. De los 5 casos reintervenidos, 4 curaron y 1 evolucionó a carcinoma de células escamosas. Conclusión: El tratamiento recomendado de la queilitis actínica es la bermellectomía, bien sea con bisturí de hoja fría o con el láser de C02, efectuando siempre el estudio histológico de la lesión para detectar de forma precoz la posible malignización, siendo también fundamental el control de los factores etiológicos (AU)

Prevalencia de lesiones orales biopsiadas en un servicio de cirugía bucal / Prevalence of biopsied oral lesions in a service of oral surgery

Introducción: Este estudio retrospectivo es la revisión de un total de 205 historias clínicas de pacientes a los que se les efectuó una biopsia de una lesión de la cavidad bucal.Pacientes y método: El estudio abarca un período de tiempo de 18 meses durante el que se realizaron 2.960 primeras visitas, de las cuales 205 presentaron lesiones susceptibles de análisis histológico.Se valoraron la edad, el sexo, la clínica y la localización de la lesión, la técnica biópsica, el tamaño del fragmento remitido, si el motivo de consulta estaba en relación con la lesión, y el resultado histológico obtenido.Resultados: De estos resultados histológicos pudimos comprobar que las lesiones más frecuentemente biopsiadas eran los quistes y entre ellos, destacaba el quiste radicular (19'5 por ciento de los casos); fueron también lesiones muy comunes en nuestra serie los granulomas periapicales (18'1 por ciento) y los fibromas (15'7 por ciento).Se encontraron gran variedad de resultados histológicos, con un total de 35 diagnósticos diferentes. Dos de las 205 biopsias realizadas resultaron ser carcinomas de células escamosas (1 por ciento).Conclusiones: La frecuencia de lesiones bucales susceptibles de ser remitidas para estudio al anatomopatólogo fue similar a la que se describe en otras publicaciones que revisan este mismo tema (AU)