Implant survival/success and peri-implant outcomes of titanium-zirconium mini implants for mandibular overdentures: Results from a 1-year randomized clinical trial

OBJECTIVE

To report the 1-year implant survival/success and peri-implant outcomes of mandibular overdentures retained by four titanium-zirconium mini implants (Straumann® Mini Implant System), and to assess how surgery and loading protocols influence these outcomes.

MATERIALS AND METHODS

A 2 × 2 factorial randomized clinical trial (RCT) tested the combined effects of two loading protocols (immediate or delayed) and two surgical approaches (flapless or flapped) on the success/survival of the mini implants, and peri-implant parameters (plaque, bleeding, sulcus depth, gingival position, and marginal bone loss). Outcomes were assessed up to 1-year after loading, and generalized estimating equations (GEEs) were used to analyze longitudinal and within-patient clustered data.

RESULTS

Two hundred and ninety-six implants were placed in 74 patients. The implant survival/success rates after 1 year were 100%, and no major biological complications were observed. After 1-year, descriptive data suggest no noticeable changes in plaque scores, whilst a reduction in bleeding scores at the 6-month and 1-year follow-ups compared to baseline. Good longitudinal stability was observed for the probing depth and gingival margin height measures. Overall mean marginal bone loss was 0.68 (±0.68) mm after 3 months and 0.89 (±0.75) mm after 1-year. The flapless protocol showed better results on soft tissue stability and health but a slightly higher risk for marginal bone loss.

CONCLUSION

The results of this RCT suggest that mandibular overdentures retained by this novel mini implant system represent a safe and predictable treatment option as confirmed by implant survival/success and peri-implant outcomes, even when flapless surgery and immediate loading protocols are adopted.

Mandibular bone characteristics, drilling protocols, and final insertion torque for titanium-zirconium mini-implants for overdentures: A cross-sectional analysis

OBJECTIVE

The aim of this study was to assess the final insertion torque values achieved using site-specific drilling protocols for a novel mini implant system for removable complete overdentures. Anatomical and technical factors influencing final insertion torque were recorded and analyzed.

MATERIAL AND METHODS

Participants were randomized to two surgical protocol groups (flapped or flapless) and all received four mini implants (Straumann® mini implant system; Straumann AG) in the anterior mandible, using a 1.6 mm needle drill and a 2.2 mm pilot drill for the implant bed site preparation. The final insertion torque was recorded as the main outcome variable during surgery. Bone type, radiographical bone density, ridge form, implant length, and the drilling protocol were considered as independent variables. Descriptive statistics, generalized estimating equations (GEE) regression, and heatmap charts were used for data analyses.

RESULTS

A total of 296 mini implants were placed in 74 patients (mean age = 64.1 ± 8.0; 64.9% female) using flapless (n = 37) or flapped (n = 37) surgeries. Mean final insertion torque was 55.8 ± 18.4 Ncm (10.5% > 35 Ncm, 48.9% between 35 and 65 Ncm, and 40.6% > 65 Ncm). The needle drill was used in only 43.9% of the implant bed sites. Higher final torque values were observed for higher bone densities (bone type I > II > III, and D1-D2 > D3-D4), highly resorbed ridge forms (5-6 > 3-4), flapped surgeries, and male patients. However, regression models showed that the likelihood of achieving optimal insertion torque (≥35 and ≤65 Ncm) was higher for females (OR = 2.14; 95%CI = 1.14-4.01; p = 0.018), ridge forms 3-4 (OR = 2.87; 95%CI = 1.05-7.85; p = 0.040), and flapless surgeries (OR = 1.96; 95%CI = 1.09-3.51; p = 0.024).

CONCLUSIONS

Sufficient primary stability for immediate loading was achieved for the majority of the mini implants placed. Surgical implant bed preparation should be site-specific to achieve optimal primary stability for immediate loading while avoiding excessive insertion torque.

Flapped versus flapless surgery and delayed versus immediate loading for a four mini implant mandibular overdenture: a RCT on post-surgical symptoms and short-term clinical outcomes

OBJECTIVE

This factorial randomized clinical trial tested the effects of the surgical approach (flapped - FPS versus flapless - FLS surgery) and loading protocol (delayed - DL versus immediate - IL) for treatment with a four mini implant mandibular overdenture.

MATERIAL AND METHODS

A total of 296 one-piece titanium-zirconium mini implants were inserted in 74 patients (IL/FLS=17; IL/FPS=18; DL/FLS=20; DL/FPS=19). Outcomes included patient's perceived surgical burdens, clinical time, implant survival, and post-surgical symptoms and complications, assessed immediately after surgery, in the 7-day and 6-week follow-ups.

RESULTS

Perceived surgical burdens were relatively low, higher for females, and no difference was found between flapped and flapless surgery. Surgical time was lower for flapless surgery. Overall symptoms were mild after 24 hours, and higher for females. Less symptoms were recorded for the flapless surgery compared to the flapped for the delayed loading patients, and flapless surgery was associated with lower risk of bleeding. No early implant failure was observed until the 6-week follow-up. Delayed was associated with discontinuous use of the prosthesis and poor function. Lower complaint rates were observed for immediate loading regardless of the surgery protocol.

CONCLUSIONS

Mini implants for mandibular overdenture is a feasible option regardless of surgical access and loading protocol, with high safety and predictable survival rates, and low incidence of post-insertion complications. Flapless surgery requires less clinical time and result in easier intraoral prosthetic incorporation of attachments compared to flapped surgeries. Immediate loading did not increase the risk of early implant failure when satisfactory primary stability was achieved.

Postsurgical oral symptoms after insertion of one or two implants for mandibular overdentures: short-term results of a randomized clinical trial

Objective

This randomized clinical trial aimed to compare the short-term postsurgical symptoms after insertion of one or two implants for retention of a mandibular overdenture. This study investigated whether the less invasive single-implant approach results in lower postoperative symptoms compared to the conventional two-implant overdenture.

Materials and methods

Patients received new complete dentures and were randomly assigned to groups receiving one or two single-stage, early-loaded hydrophilic implants, inserted in the midline (n = 23), or the lateral incisor-canine area bilaterally (n = 24). Patient-reported postoperative symptoms were measured in a 0–100 visual analogue scale concerning pain in the surgical area, pain when chewing, bleeding, swelling, and unpleasantness. Data collection occurred 24 h and 7 and 21 days after surgery. Demographic and clinical features (smoking habit, classification of the residual ridges, and mucosal width and thickness at the implant sites), osteotomy for alveolar bone reduction, and surgery time were tested as predictors of symptom levels.

Results

Overall reported symptoms were mild and self-limited, with high rates of complete remission after the early loading period of 3 weeks. Progressive improvement of symptoms occurred from the 24-h to the 7-day and 21-day follow-ups (p < 0.001), similarly in both groups. None of the clinical predictors was significantly associated with the changes in symptoms.

Conclusions

Findings suggest that the insertion of one or two implants may result in similar postoperative outcomes.

Clinical relevance

The severity of short-term postoperative symptoms may not be a critical factor for the decision between overdenture treatment with one or two implants.

Immediate Rehabilitation of Elderly Patient with Large Proportion Residual Cyst

Abstract Residual cyst is consequence of a radicular cyst incomplete removal. This paper presents the case of a patient with residual cyst of unusual size located in the pre-maxilla causing large bone defect rehabilitated by titanium mesh. A 78-year-old male patient with good general health sought treatment reporting maladjustment of the upper dental prosthesis due to a volumetric increase with one year of evolution. Patient history and clinical and complementary exams led to diagnosis of residual cyst. Due to the cyst size and bone resorption, after the lesionremoval, a titanium mesh was fixed and a membrane positioned, in an attempt to reduce bone deformity and induce tissue repair to avoid functional and aesthetic sequelae. The treatment restored maxillary sinus health and provided satisfactory aesthetic contours to the patient’s face, enabling a proper prosthetic rehabilitation and proved to be a viable alternative for the treatment of similar cases.Keywords: Maxillary Sinus. Odontogenic Cysts. Surgical Mesh.ResumoO cisto residual é consequência da remoção incompleta de um cisto radicular. Este artigo apresenta o caso de um paciente com cisto residual de tamanho incomum localizado na região pré-maxilar causando grande defeito ósseo reabilitado com uso de tela de titânio. Paciente do sexo masculino, 78 anos, com boa saúde geral procurou tratamento com desajuste da prótese dentária superior, devido a um aumento volumétrico com um ano de evolução. A história do paciente e exames clínicos e complementares levaram ao diagnóstico de cisto residual. Devido ao tamanho do cisto e à reabsorção óssea, após a remoção da lesão, uma tela de titânio foi fixada e uma membrana posicionada, na tentativa de reduzir a deformidade óssea e induzir a reparação tecidual para evitar sequelas funcionais e estéticas. O tratamento restaurou a saúde do seio maxilar e forneceu contornos estéticos satisfatórios para a face do paciente, permitindo uma reabilitação protética adequada e provou ser uma alternativa viável para o tratamento de casos semelhantes.Palavras-chave: Cistos Odontogênicos, Seio Maxilar, Telas Cirúrgicas

Impact of cone-beam computed tomography on implant planning and on prediction of implant size

The aim was to investigate the impact of cone-beam computed tomography (CBCT) on implant planning and on prediction of final implant size. Consecutive patients referred for implant treatment were submitted to clinical examination, panoramic (PAN) radiography and a CBCT exam. Initial planning of implant length and width was assessed based on clinical and PAN exams, and final planning, on CBCT exam to complement diagnosis. The actual dimensions of the implants placed during surgery were compared with those obtained during initial and final planning, using the McNemmar test (p < 0.05). The final sample comprised 95 implants in 27 patients, distributed over the maxilla and mandible. Agreement in implant length was 50.5% between initial and final planning, and correct prediction of the actual implant length was 40.0% and 69.5%, using PAN and CBCT exams, respectively. Agreement in implant width assessment ranged from 69.5% to 73.7%. A paired comparison of the frequency of changes between initial or final planning and implant placement (McNemmar test) showed greater frequency of changes in initial planning for implant length (p < 0.001), but not for implant width (p = 0.850). The frequency of changes was not influenced by implant location at any stage of implant planning (chi-square test, p > 0.05). It was concluded that CBCT improves the ability of predicting the actual implant length and reduces inaccuracy in surgical dental implant planning.

Risk factors for maxillofacial injuries in a Brazilian emergency hospital sample

Background

Maxillofacial injuries occur in a significant number of trauma patients. Epidemiological assessments are essential to reaffirm patterns, identify new trends and develop clinical and research priorities for effective treatment and prevention of these injuries.

Objective

The aim of this study was to identify the epidemiological profile and risk factors associated with maxillofacial trauma treated at a referral emergency hospital for the Public Health System in the State Capital of Goiás, Brazil.

Material and Methods

A cross-sectional study was designed including 530 patients with maxillofacial trauma, 76% male, with a mean age of 25.5±15.0 years. Data were collected between May 2003 and August 2004 over weekly shift-working periods. Results: The main causes of trauma were traffic accidents (45.7%) and physical assaults (24.3%), and differences in etiological factors were identified according to gender (p<0.001). The distribution of patients according to age and etiology showed significant differences for traffic accidents (p<0.01), physical assaults (p<0.001), falls (p<0.001) and sport injuries (p<0.01). In the multinomial logistic regression analysis (R² = 0.233; p<0.05), age was associated with injury in traffic accidents and falls (p<0.01), sports-related accidents were associated with males (p<0.05), and alcohol consumption with assaults and traffic accidents (p<0.001). Facial soft tissue lesions were found in 98% of patients and facial fractures in 51%.

Conclusions

The significant association of maxillofacial trauma with young males and alcohol consumption reinforces the need for educational strategies and the development of policies for the prevention and reduction of associated damage in this specific risk group.

Implant-supported obturator overdenture for extensive maxillary resection patient: a clinical report

This clinical report presents an implant-retained obturator overdenture solution for a Prosthodontic Diagnostic Index Class IV maxillectomy patient with a large oronasal communication and severe facial asymmetry, loss of upper lip and midfacial support, severe impairment of mastication, deglutition, phonetics, and speech intelligibility. Due to insufficient bone support to provide satisfactory zygomaticus implant anchorage, conventional implants were placed in the body of the left zygomatic arch and in the right maxillary tuberosity. Using a modified impression technique, a cobalt-chromium alloy framework with three overdenture attachments was constructed to retain a complete maxillary obturator. Patient-reported functional and quality of life measure outcomes were dramatically improved after treatment and at the two-year follow-up.