Clinical Peri-Implant Parameters and Marginal Bone Loss for Early Mandibular Implant Overdentures: A Follow-Up of 60 Months

Background and Objectives: Despite the identified benefits of early implant loading, studies have questioned its advantages compared to delayed loading in edentulous patients. This study aimed to evaluate clinical peri-implant parameters and marginal bone loss around early placed and loaded mandibular implant overdentures with a 60-month follow-up. Materials and Methods: In this prospective cohort study, 43 patients were enrolled to receive 86 early loading sub-crestal dental implants through prosthetic guides. Implant overdentures were supported by two isolated implant locator attachments between two mental foramens. Clinical peri-implant parameters, including plaque index (PI), bleeding index (BI), peri-implant pocket depth (PIPD), and marginal bone loss (MBL) were evaluated using standardized techniques at 1, 12, 24, 36, 48, and 60 months follow-up. At 60 months, complications associated with implant overdentures (IOD's) were noted. The mean comparison of peri-implant clinical parameters was performed through ANOVA test. A p-value of ≤0.05 was taken as significant. Results: Out of the total 43 enrolled patients, 8 patients were lost during follow-up; as a result, 35 patients completed the 5 years follow-up. The mean values of PI, BI, and PIPD increased with no statistical difference (p > 0.05). For marginal bone loss, an increase in the mean values was noted at different time intervals with statistical differences (p < 0.001). The most common complications noted were loosening of the abutment, occlusal adjustment, retentive locator loosening and replacement, and relining of the denture. Conclusions: Early placement of IODs failed to prevent bone loss over time and was associated with complications, predominantly consisting of abutment loosening, occlusal adjustments, broken retentive locator components, relining, and rebasing.

Proof of Concept of a New 3D-Guided System for a Single Implant Overdenture in the Mandible: An In Vitro Study

PURPOSE

To evaluate the precision and efficiency of a novel guide system for single implant placement in the mandibular symphyses and to evaluate whether the outcome is affected by the level of operator experience.

MATERIALS AND METHODS

A total of 90 implants were placed in three different mandibular cast types (Cawood and Howell class III, IV, and V). For each model, a complete denture was 3D printed. A polyether ether ketone rail with a guide sleeve was embedded in the middle of the denture. To determine the ideal implant position, the sleeve could be moved in a buccolingual direction. Adjustment of implant angulation was possible, and an angle correction of 0, 12, or 24 degrees was available. A total of 30 clinicians were divided into three groups: group 1 (experienced, n = 10), group 2 (beginner, n = 10), and group 3 (inexperienced, n = 10). Each clinician was asked to plan and perform a guided flapless implant placement in the mandibular symphysis. Two preoperative CBCT scans were taken; the first was to verify the planning, and the second was to adjust the planning if needed. Finally, a postoperative CBCT scan was taken to compare the planning to the final implant position.

RESULTS

Based on the first CBCT, the clinicians adjusted their planning by an average of 1.66 ± 1.65 mm coronally, 2.41 ± 2.44 mm apically, and by a mean angular correction of 6.08 ± 0.77 degrees. After implant placement, the mean deviation from the planned implant position was 0.87 ± 0.58 mm at the coronal aspect and 0.98 ± 0.64 mm at the apical aspect. The mean angular deviation was 6.05 ± 0.71 degrees. Overall, there were no significant differences in coronal and apical deviation (P > .05) based on the level of experience. In terms of angulation, a significant difference was found in both planning (P = .049) and placement (P = .038) between beginners and experienced clinicians.

CONCLUSIONS

Guided implant placement of a single implant in the mandibular symphysis using a removable denture with guide sleeve had an acceptable level of accuracy. Clinicians with limited experience spent more time on the procedure, resulting in less angular deviation during implant planning and placement compared to experienced clinicians.

Current Evidence for the Management of Edentulous Atrophic Mandible Fractures: A PRISMA-SWiM Guided Review

Study Design

PRISMA-SWiM guided systematic review.

Objective

1. Provide consistent evidence regarding the management of atrophic mandible fractures; 2. To search, evaluate and validate existing guidelines if any for the management; 3. Provide evidence regarding specific management of condylar fractures in the atrophic mandible; 4. To address the clinical applicability of bone grafts.

Methods

A systematic review was conducted using the PRISMA-SWiM protocol. PROSPERO ID: CRD42021235111. Studies with adequate data on outcome, treatment methods were selected. Isolated case reports, case series, and non-human studies were excluded. Quality assessment was done using Newcastle -Ottawa scale. The level of evidence was assessed using Oxford Level of Evidence.

Results

Mandibular body was the most common type of fracture. Self falls and RTA were the most common etiologies. Condylar fracture was most commonly managed conservatively with ORIF employed in few studies. For the mandible compression and non-compression osteosynthesis were used. Bone grafts were used in cases with segmental defects or cases requiring augmentation.

Conclusions

There is lack of proper evidence to definitely conclude any single treatment modality. However, the consensus is towards ORIF. Reconstruction plates are preferred by many authors. However, unilateral fractures may be managed by miniplates. Bilateral fractures require more rigid fixations. Open reduction and internal fixation of condylar fracture is indicated in cases with displacement or low-level fractures.

Immediate loading of dental implants in edentulous mandibles using Locator attachments or Dolder bars: A 9-year prospective randomized clinical study

AIM

To evaluate the long-term survival, incidence of prosthetic/technical and biological complications and the oral-health-related quality of life in patients with an edentulous mandible who were fitted with overdentures on two immediately loaded implants in the symphyseal area.

MATERIALS AND METHODS

Forty-six patients with edentulous mandibles received two immediately loaded implant-retained dentures with either two Locator attachments or egg-shaped bar attachments. Implant outcomes were recorded after a period of observation of 9 years and included prosthetic complications, modified gingiva index (mGI), modified plaque index (mPI), oral health impact profile (OHIP-G) and radiographic estimation of bone loss.

RESULTS

In 2020/2021, 27 patients with 54 implants were still available for follow-up. In total, nine implants in six patients were lost. Survival was 89.1% in the bar group and 91.3% in the Locator group. Implant success was 84.6% in the Locator group and 76.9% in the bar group. The mPI values were significantly higher in the bar group than in the Locator group, whereas no difference was seen in the mGI values. During the observation period, 152 prosthetic complications occurred, but the OHIP-G score did not differ significantly.

CONCLUSIONS

There was no difference in implant survival between Locator or joint bar attachments over a 9-year observation period. Joint bar attachments were associated with slightly more complications, while patients in the Locator group were able to maintain better oral hygiene. The study was registered in the German Register of Clinical (Trials DRKS00004245).

The effect of short implants placed in the posterior region on tilted implants in the 'All-On-Four' treatment concept: a three-dimensional finite element stress analysis

This study aims to investigate the impact of a short implant placed behind the mental foramen with the all-on-four treatment concept using the three-dimensional (3D) finite element stress analysis (FEA).Six different finite element analysis models were designed according to tilted implant angle (17° and 30°), presence of short implants, and short implant diameter (4.1 mm and 4.8 mm). A 100 N force was applied vertically from the central fossa of the lower right second premolar tooth. Maximum equivalent (von Mises) and Minimum/Maximum principal (Pmin/Pmax) stress values and distributions were evaluated by 3D-FEA.The highest stress value among tilted implants was in the T17 group. T30 was the group that caused the most stress in the cortical bone. Adding the short implant to the all-on-four design reduced von Mises stress on multi-unit abutments, abutment screws, and tilted implants in both the 17° and 30° groups. At the same time, it reduced Pmin/Pmax stresses in cortical bone. Similar behavior was observed in terms of stress values and distributions for the 4.1 and 4.8 mm short implant groups.The results show that short implant placement in the posterior region in the all-on-four concept reduces stress on the bone, implants, and prosthetic parts, regardless of the diameter of the short implant. In cases where biomechanical risks such as parafunctional habits and poor bone quality increase, we recommend increasing the number of implants with short implants.

Survival and Complications of Single Dental Implants in the Edentulous Mandible following Immediate or Delayed Loading: A Randomized Controlled Clinical Trial

Introduction

The lifespan of an edentulous mandible with one median implant to hold a full denture for 24 months was evaluated to see if the early loading had any impact on it. Single-implant denture retention for the mandibular region was proposed by "Cordioli et al. in the 1990s.

Objectives

Whether rapid loading and placement of a "single median implant" may result in the implant survival rate comparable to rehabilitation with a single implant and second-stage surgery.

Methods

It was found that 81 of the 158 implant recipients had quick loading, whereas the rest had delayed loading (77 patients). Patients in the context of "delayed loading group" had follow-up appointments at 1 month, 4 months, 12 months, and 24 months. In addition, the nine implants failed in the 3 months after loading in a quick loading group, while just one implant failed before loading. Median implant survival at 2 years was the study's main goal. Direct loading had a 7% fatality rate advantage over traditional loading because of the alleged advantages of immediate loading, including the avoidance of second-stage surgery. Prosthetic problems were evaluated using Fisher's exact test.

Results

A higher rate of implant survival was not seen when implants were loaded more quickly (P = 0.81). A statistically significant difference (P = 0.019) was seen in implant survival between the therapy groups.

Conclusion

Single implant loading in an edentulous mandible has a worse survival rate than delayed loading, according to all available research.

The Single Midline Implant in the Edentulous Mandible-Current Status of Clinical Trials

The single midline implant in the edentulous mandible is a treatment concept that has often been controversially discussed. Nearly 30 years ago, the first available clinical results revealed high implant survival rates and remarkable improvements in oral comfort, function, patient satisfaction and oral health-related quality of life for edentulous patients compared to the situation with no implant. However, the clinical trials were predominantly conducted with a small number of patients over a short to medium follow-up period. Today, numerous clinical investigations on the single midline implant in the edentulous mandible, which increasingly include longer-term observation periods, are available. It is the aim of this overview to present the current literature and to highlight the clinical problems. This article is a 2023 update of a review published by the authors in the German language in 2021 in the German journal Implantologie. In total, 19 prospective clinical trials with a follow-up period of 0.5-10 years were analyzed. Over this observation period, single implants with modern rough implant surfaces in the edentulous mandible reveal high implant survival rates of between 90.9 and 100% when a conventional delayed loading protocol was applied.

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.

The Effect of General Bone Mineral Density on the Quantity and Quality of the Edentulous Mandible: A Cross-Sectional Clinical Study

BACKGROUND

Osteoporosis is a disease which is characterized by a decrease in general bone mineral density (BMD), resulting in decreased bone strength and an increased risk of bone fractures. The effect of reduced BMD on the jawbones is still not fully understood. The purpose of the study was to evaluate the impact of BMD on the quality and quantity of the edentulous mandible.

METHODS

The present study included 127 edentulous postmenopausal women who underwent cone beam computed tomography (CBCT) examinations. BMD measurements of the lumbar spine and femoral necks were performed by dual-energy X-ray absorptiometry. In the cross-sectional CBCT images, three different areas of the mandible (lateral incisor, first premolar, and first molar) were selected. The complete mandibular, trabecular, and cortical bone volumes were measured. All measurements were performed on the total mandibular area, and the basal and alveolar parts of the mandible.

RESULTS

The volume of the cortical bone was reduced for females with reduced BMD in the lateral incisor and first premolar regions, both in the total mandibular area and in the basal part of the mandible. The trabecular bone volume statistically significantly increased when the BMD decreased in the complete mandibular area and the basal part of the mandible (linear regression). The total bone volume significantly decreased with a decrease in BMD in the basal part of the mandible.

CONCLUSIONS

Reduced BMD has a negative effect on the quantity and quality of bone in the basal part of the edentulous mandible.

Implant-Supported Prostheses in the Edentulous Mandible: Biomechanical Analysis of Different Implant Configurations via Finite Element Analysis

This study explores the implant-supported prosthetic treatment alternatives of the edentulous mandible from a biomechanical point of view by means of a Finite Element Analysis (FEA). Finite element (FE) models were used to simulate cases treated with six, five, and four, implants and a fixed prosthesis with a cantilever. In the four implant treatments, three cases were analyzed; the posterior implants were placed in axial positions, angled at 30° and 45°. Cases with six and four axially placed implants were also analyzed by placing the posterior implants distally to the foramen, thus eliminating the cantilever in the prostheses. In the cases with implants between foramina, the highest values for the principal strains and von Mises stresses were observed in the case with four implants where the posterior implants were angled at 45°. Cases with implants placed distally to the foramen and without a cantilever showed much lower bone stress and strain levels compared to cases with implants between foramina. From a biomechanical point of view, it seems to be a better option to use implants positioned distally to the foramen, eliminating cantilevers.

A comparative evaluation of neurophysiological activity, active tactile sensibility and stereognostic ability of complete denture prosthesis, and implant-supported prosthesis wearer-A pilot study

AIM

The study aimed to evaluate the effect of implant-supported prosthesis in completely edentulous participants in terms of osseoperception ability, neural activity, and stereognostic ability in comparison to removable prosthetic options.

MATERIALS AND METHODS

A total sample of 18 patients, irrespective of gender and age were allocated into three groups according to the three-treatment protocol (upper and lower complete denture, upper complete denture opposing lower implant-retained overdenture, implant-supported fixed prosthesis in both arches). Four weeks after completion of the treatment procedure active tactile sensibility (ATS) was checked by using varying thicknesses (12, 40, 80, 100, 200 μ) of articulating foils and papers. Functional magnetic resonance imaging (fMRI) was performed to record neurophysiological activity in cerebral cortex in all the participants. Various forms of test pieces (heat cure acrylic resin) were used to evaluate stereognostic ability. Data regarding the neurophysiological activity were analyzed by using Krushkal-Wallis test and p ≤ 0.05 was considered to be statistically significant. Data from stereognostic ability test procedure and ATS were compared by using chi-squared test and p ≤ 0.05 was considered to be statistically significant.

RESULTS

Statistically significant difference was found in between the articulating foils in terms of true negative responses as the foil thickness increased in participants wearing complete denture in both the arches (p = 0.004) and implant-supported fixed prosthesis in both the arches (p = 0.010). Participants in implant-supported fixed prosthesis group showed significantly more activation in primary motor cortex (right side), somatosensory cortex (left side), angular gyrus (both sides), temporal lobe (left) compared to other groups. No significant difference found in thalamus and premotor cortex region in between the participants of different groups. No statistically significant difference found in between the groups in terms of true responses identifying correct shapes. Mean number of correct responses in stereognostic ability test were 4.16 (83.33%), 3.5 (70%), 3.83 (76.66%) for participants of complete denture group, upper complete denture opposing lower implant retained overdenture group, and implant-supported fixed prosthesis group, respectively.

CONCLUSION

Primary motor cortex, somatosensory cortex, and other regions of brain were diffusely activated in participants wearing implant-supported fixed prosthesis in both the arches. Less number of false responses were recorded in participants of implant-supported fixed prosthesis group and upper complete denture opposing lower implant-retained overdenture group in ATS test compared to participants wearing complete denture in both the arches.

[Experimental design of the lower jaw functional loading for implant-supported restoration in unfavorable clinical conditions]

THE AIM OF THE STUDY

Was to create a finite element design to evaluate the masticatory stress distribution on the full fixed prosthesis with three supporting implants and the mandibular bone in the conditions most closely resembling the real ones.

MATERIALS AND METHODS

The geometric design was created with the results of a CBCT of a real patient. The transfer of the DICOM into STL format was carried out in the Mimics Medical 21 program, in which the author's splinting device for the implant was designed. The actual thicknesses of the patient's compact and cancellous bone layers were measured with Romexis ver. 4.5.1. Scanning of the artificial dentition was performed with the iTero Element 2 Version 1.7 which created an object in STL format. Design was performed in the package for finite element analysis Ansys 19.3. Tetrahedral elements of the second order were used for calculation. The structural elements were connected in the model by a rigid «Bonded» contact.

RESULTS

A finite element model has been created for the experimental load design on the lower jaw for immediate implant restoration with few supports in combination with a device for stabilizing the implant in unfavorable clinical conditions. It is shown that the designed finite element model takes into account the biomechanics of the prosthesis with few supports. When calculating, the entire model was fixed to the mandibular process at its base, and was loaded with a force of 500 N, distributed over the teeth. The values of the maximum stresses obtained in the elements were 51.8 MPa for the compact layer and 245 MPa for titanium elements.

CONCLUSION

Thus, we created personalized geometric and finite element models for calculating the distribution of functional load on a long full fixed implant-supported prosthesis with few artificial supports, which makes the experimental results more accurate and correct.

Implant Treatment by Guided Surgery Supporting Overdentures in Edentulous Mandible Patients

INTRODUCTION

This study aimed to show the clinical outcomes of implants inserted by guided surgery supporting mandibular overdentures in edentulous patients.

PATIENTS AND METHODS

Mandibular edentulous patients were diagnosed with an oral examination, cone-beam computerized tomography, and diagnostic casts for intermaxillary relations and treated with overdentures over two implants by guided surgery. After flapless surgery, implants were early loaded with an overdenture at 6 weeks.

RESULTS AND DISCUSSION

Fourteen patients (nine females and five males) were treated with 28 implants. Four patients (28.6%) had a previous history of periodontitis. Five patients (35.7%) were smokers. Nine patients (64.3%) suffered from systemic diseases (i.e., diabetes, cardiovascular diseases). The clinical follow-up of the study was 44.7 ± 31.4 months. Clinical outcomes showed a global success of 100% of implants. Fourteen overdentures were placed in the patients over the implants. Mean marginal bone loss was 1.25 mm ± 0.95 mm. Four patients (28.6%) showed some kind of mechanical prosthodontic complications. Six implants (21.4%) were associated with peri-implantitis.

CONCLUSIONS

This study indicates that treatment of mandibular edentulous patients with overdentures by guided surgery and early loading of implants placed appears to be a successful implant protocol.

Implant Survival in Immediately Loaded Full-Arch Rehabilitations Following an Anatomical Classification System-A Retrospective Study in 1200 Edentulous Jaws

This retrospective study analyzed implant survival of immediate implant-supported fixed complete denture (IFCD) treatment options (TOs) based on the level of alveolar atrophy (CC). Records of 882 patients receiving a total of 6042 implants at one private referral clinic between 2004 and 2020 were considered. The mean follow-up period was 3.8 ± 2.7 years. Cumulative implant survival rates (CSRs) were analyzed as a function of CCs and TOs according to Mantel-Haenszel and Mantel-Cox. Hazard risk ratios for implant loss were compared using Cox regression. Confounding factors were identified using mixed Cox regression models. The 2- and 5-year CSRs were 98.2% and 97.9%, respectively. Maxillary 2- and 5-year CSRs were lower (97.7% and 97.3%) compared to mandibular CSRs (99.8% and 98.6%) (p = 0.030 and 0.0020, respectively). The CC did not influence CSRs of IFCDs in the mandible (p = 0.1483 and 0.3014, respectively) but only in the maxilla (p = 0.0147 and 0.0111), where CSRs decreased with increasing atrophy. TOs did not statistically differ in terms of survival rate for a given level of alveolar atrophy. The adaption of IFCD treatments to the level of atrophy and patient-specific risk factors can result in high CSRs, even at different levels of bone atrophy.

Immediate Loading of Implants Placed by Guided Surgery in Geriatric Edentulous Mandible Patients

The aim of this study was to show the clinical outcomes of the immediate loading of implants inserted by guided surgery in edentulous mandible patients. Edentulous mandible patients were diagnosed with oral examination, cone beam computerized tomography and diagnostic casts for intermaxillary relations and treated with 8–10 implants for rehabilitation with guided surgery and immediate loading. After flapless surgery, implants were loaded with an immediate acrylic temporary prosthesis. After a period of six months, a ceramic definitive full-arch prosthesis was placed. A total of 22 patients (12 females and 10 males) were treated with 198 implants. Eleven patients (50%) had a previous history of periodontitis. Six patients (27.3%) were smokers. The follow-up was 84.2 ± 4.9 months. Clinical outcomes showed a global success rate of 97.5% of implants. Five implants were lost during the healing phase with provisional prosthesis. Twenty-two fixed full-arch rehabilitations were placed in the patients over the 193 remaining implants. Mean marginal bone loss was 1.44 mm ± 0.45 mm. Six patients (27.3%) showed some kind of mechanical prosthodontic complication. Eighteen (9.3%) of the 193 remaining implants were associated with peri-implantitis. The antecedents of peri-implantitis are critical elements for the survival of the implants. The loss of implants was significant in patients who smoked up to 10 cigarettes, compared to non-smokers. Peri-implantitis is one of the key elements in the long-term follow-up of implants and it was more manifest in smoking patients, and in those with a history of peri-implantitis. Marginal bone loss was more significant in smokers. Full-arch rehabilitation is presented as a predictable alternative with minor fatigue problems that are easily solvable.

Articulation, oral function, and quality of life in patients treated with implant overdentures in the mandible: A prospective study

BACKGROUND

Modifications of facial and oral structures affect aesthetic appearance, orofacial functions, and have impact on quality of life.

PURPOSE

This study determined alterations of articulation, oromyofunctional behavior, and Oral Health Related Quality of Life (OHRQoL) in patients replacing complete removable dentures by implant retained overdentures in the mandible.

MATERIALS AND METHODS

Twenty-one fully edentulous patients received mandibular overdenture retained on a bar connecting two titanium dental implants. Patients were evaluated after receiving a new set of fully removable dentures (stage 1), after surgery during provisionalization on healing abutments (stage 2), and after final connection to the bar (stage 3). Assessments were taken by speech therapists and included evaluation of: articulation (picture naming and reading); oromyofunctional behavior; OHRQoL (OHIP-14 questionnaire), and overall satisfaction and speech (VAS). To measure changes over time, Wilcoxon matched-pairs signed-rank-test and McNemar test was used.

RESULTS

There was no significant impact of the treatment on speech nor on the results of oromyofunction. In stage 1, patients had different kinds of articulation errors (mean:1.21) which evolved to 0.71 and 0.67. In stage 3, especially problems with the /s/ sound are seen in 37% (7/19) of the participants. Results of OHRQoL and satisfaction reveal that the average of satisfaction with oral health evolved from 67% to 63% and finally 78%. OHIP-14 total score was 17.4/56 in stage 1, remained unchanged in stage 2 and evolved in stage 3 to 9.8/56 (P: .010). This indicates improvement. Satisfaction with speech evolved significantly from 68% pretreatment to 82% in stage 3 (P: .013).

CONCLUSION

Despite existing articulation and oromyofunctional disorders after treatment, people are very satisfied with their OHRQoL and their speech. Impact of mandibular denture wearing on OHRQoL declines once connected. It's important to inform patients that speech and oromyofunctional disorders may occur during treatment where especially the /s/ sound is vulnerable.

Decision-Making in Implantology-A Cross-Sectional Vignette-Based Study to Determine Clinical Treatment Routines for the Edentulous Atrophic Mandible

This cross-sectional study aimed to investigate the influence of possible factors in the patient history on decision making in the therapy for a severely atrophied edentulous mandible. A vignette-based survey among 250 maxillofacial and oral surgeons was conducted. Determinants that could influence the therapy decision were patient age, smoking, fear of surgery, and radiotherapy in the head and neck area (the implant region is not in the direct radiation area). To achieve a suitable implant site, the options offered to the surgeons were bone split, bone block, augmentation with bone substitute material, and bone resection. There also was the option of rejecting any therapy. The response rate was 47%. Patient age, radiotherapy, and fear of surgery did not influence the approval of a therapy. Smoking was associated with a significantly lower endorsement of a treatment. Resection was preferred by a large majority to all other forms of therapy, regardless of the four determinants. Surgeons tend to refrain from bone block transplants in older patients. In summary, it can be said that, of the four determinants, only smoking influenced treatment refusal. Bone resection is the preferred therapy independent of all determinants.

Outcome of peri-implant maintenance care in patients with an implant-supported lower denture-A 3.5-year retrospective analysis

Background

Implant‐supported overdentures represent a successful treatment for edentulous patients. As early diagnosis, detection and supportive care are considered key factors for the prevention of peri‐implant diseases, consistent maintenance of these implants is becoming increasingly relevant.

Purpose

This retrospective analysis evaluated a cohort of edentulous patients with a mandibular implant‐supported overdenture over a period of 3.5 years during which the peri‐implant tissues were assessed.

Materials and Methods

A total of 108 patients that had consistently adhered to the annual maintenance appointments was selected. The clinical peri‐implant pocket probing depth (PiPPD) and peri‐implant bleeding on probing score (PiBOP) were investigated. Data from the 3.5‐year follow‐up were compared to data from the baseline assessment.

Results

A 100% implant survival was reported after 3.5 years. The mean PiBOP showed a significant decrease over time (P = .028). The mean PiPPD was found significantly deeper for male patients both at baseline (P = .004) and 3.5‐year follow‐up (P < .001). Besides, the PiPPD for locator anchorages was found significantly deeper compared to ball anchorages at the 3.5‐year follow‐up (P = .026).

Conclusion

In those patients that adhered to the annual maintenance visits during the 3.5 years after implant surgery a stable peri‐implant condition was observed. As future consideration, the comparison of the clinical outcomes of patients participating in the maintenance program with those that did not would make this observation even more meaningful.

5-year randomized multicenter clinical trial on single dental implants placed in the midline of the edentulous mandible

OBJECTIVES

This multicenter randomized controlled clinical trial was conducted to investigate whether the loading protocol of single dental implants placed in the midline of edentulous mandibles will influence the implant survival or prosthetic maintenance.

MATERIALS AND METHODS

In total, 158 patients were randomly assigned either to the immediate loading group (n = 81) or to the delayed loading group (n = 77). All implants were loaded with an overdenture retained by a ball attachment.

RESULTS

After 5 years, 102 patients attended the follow-up investigation. Immediately loaded single implants in the midline of the edentulous mandible revealed a statistically significant lower survival rate than implants loaded conventionally over an observation period of 5 years. In the immediate loading group, 9 implants failed within the first three months of implant loading. No further implant loss was recorded for this group. Two implants failed in the delayed loading group, whereas one implant had to be removed during second-stage surgery and the second five years after implant loading. Non-inferiority of the survival rate of the midline implant of the immediate loading group, compared with the delayed loading group, could not be shown (p = .79, CI immediate loading: 74.9%; 100.0%, CI delayed loading: 73.0%; 100.0%). The observed difference in implant survival between the two treatment groups over time was statistically significant.

CONCLUSIONS

The results of the present study indicate that immediate loading of a single mandibular implant in the edentulous mandible should be considered only in exceptional cases.

The versatile "lip switch" or transitional flap vestibuloplasty combined with alveoloplasty and implant placement to treat atrophic mandibles with inadequate vestibules and attached tissue: A case series and review of the literature

INTRODUCTION/AIMS

The edentulous mandibular ridge and associated shallow vestibule are often seen as a challenge in the oral rehabilitation of patients. Dental implants can provide an improvement in mastication and patient satisfaction. The aim of this study is to utilize a preprosthetic mucosal flap combined with a repositional periosteal flap concomitant with an alveoloplasty and placement of endosteal implants as a single-stage procedure in the anterior mandible. This approach provides a valued alternative for dental rehabilitation in patients with poor masticatory efficiency using a conventional denture.

METHODS

Eight patients underwent the preprosthetic surgical plan in the oral surgery clinic of the dental school during a 1-year period. Age, sex, preoperative, and postoperative vestibular depth, as well as hard and soft tissue elements were measured (P < .05) at 4-6 months.

RESULTS

Mean age was 53 years ± 14.62 (N = 8). Anterior mandible height was 19 ± 4.8 mm. A significant difference was measured using a two-tailed Student's t-test between pre- and postoperative vestibular depths, respectively (3.9 mm vs 10.5 ± 0.96 mm; P < .01).

CONCLUSIONS

A lip switch vestibuloplasty combined with placement of two implants provide a one-stage procedure that is convenient, provides a shorter postoperative period, and can be financially affordable. Future research requires larger sampling to support this treatment as a standard of care.

Biomechanical comparison of implantation approaches for the treatment of mandibular total edentulism

Applying four anterior implants placed vertically or tilted in the mandible is considered to provide clinically reasonable results in the treatment of mandibular posterior edentulism. It is also reported that a combination of four anterior and two short posterior implants can be an alternative approach for the rehabilitation of severe atrophy cases. In this study, we aimed to evaluate the biomechanical responses of three different implant placement configurations, which represent the clinical options for the treatment of mandibular edentulism. Three-dimensional models of the mandible, prosthetic bar, dental implant, abutment, and screw were created. Finite element models of the three implant configurations (Protocol 1: Four anterior implants, Protocol 2: Four anterior and two short posterior implants, Protocol 3: Two anterior and two tilted posterior implants: All-on-4™ concept) were generated for 10 patients and analyzed under different loading conditions including chewing, biting, and impact forces. Protocol 2 led to the lowest stress concentrations over the mandible among the three protocols (p < 0.016). Protocol 2 resulted in significantly lower stresses than Protocol 3 and Protocol 1 over prosthetic bars under chewing forces (p < 0.016). None of the implant placement protocols consistently exhibited the lowest stress distribution over abutments. The lowest stresses over dental implants under the chewing, biting, and impact forces were obtained in Protocol 1, Protocol 2, and Protocol 3, respectively (p < 0.016). Protocol 3 was the best option to obtain the lowest stress values over the screws under all types of loading conditions (p < 0.016). In conclusion, Protocol 2 was biomechanically more ideal than Protocol 1 and Protocol 3 to manage the posterior edentulism.

Impact of implant superstructure type on oral health-related quality of life in edentulous patients

BACKGROUND

The effect of the type of implant superstructure on oral health-related quality of life (OHRQoL) among edentulous patients remains controversial.

PURPOSE

The purpose of this study is to investigate the association between the type of implant superstructure and OHRQoL.

MATERIALS AND METHODS

Seventy-two completely edentulous patients who received implant fixed complete dentures (IFCDs) or implant overdentures (IODs) were administered the Oral Health Impact Profile (OHIP) questionnaire during the post-treatment maintenance period. The OHIP summary score, as well as the four dimension scores, were calculated to evaluate OHRQoL.

RESULTS

The mean OHIP summary score for the IFCD group tended to be lower than that for the IOD group, but this difference was not statistically significant (19.9 ± 21.9, 22.8 ± 18.2, respectively; P = .57). However, a significant group difference was found in the four dimension scores (P < .01), with the OHIP item scores representing masticatory function being significantly lower in the IFCD group than in the IOD group (P < .05).

CONCLUSIONS

Our results suggested that patients with an IOD exhibited comparable OHRQoL to those with an IFCD, with the exception of perceived masticatory function.

Prevalence and Morphology of Mandibular Incisive Canal: Comparison among Healthy, Periodontitis and Edentulous Mandibles in a Population of the Beijing Area Using Cone-beam Computed Tomography

OBJECTIVE

To evaluate and quantify the prevalence and morphology of the mandibular incisive canal (MIC) comparatively among healthy, periodontitis and edentulous mandibles using cone-beam computed tomography (CBCT).

METHODS

CBCT images of 1,070 hemimandibles from 535 consecutive patients, including 448 with healthy dentition, 42 with severe periodontitis mandibles and 45 with edentulous mandibles, were retrospectively analysed. MICs were identified, and linear measurements were performed. Statistical analyses were conducted to investigate differences in the prevalence and morphology of MICs relative to gender, laterality, age group and dental status.

RESULTS

The MIC was observed in 92.8% of 1,070 hemimandibles. No significant differences of MIC prevalence were found between left and right sides, or between healthy and periodontitis mandibles. However, males had a higher prevalence of MIC than females, and patients with dentate mandibles had a higher prevalence of MIC than those with edentulous mandibles. For dentate mandibles, MICs started most commonly below the first premolar (51.9%) and ended around the canine (58.5%). The mean diameter of MIC was 2.5 ± 0.5 mm at origin, and 20.6% of MICs began with a diameter of ≥ 3 mm. The mean length of MIC was 13.4 ± 3.3 mm. The mean distances from the MIC to the labial cortex, lingual cortex, alveolar ridge and inferior border of mandible were 3.7 ± 0.9, 5.1 ± 1.6, 19.5 ± 3.8 and 8.9 ± 1.7 mm, respectively. Moreover, significant differences of measurements were found relative to gender, age group, and dental status.

CONCLUSION

Due to the large variations in size and course of MICs, special caution should be exercised in any individual surgery affecting the anterior mandible.

Immediate versus delayed loading of mandibular implant-retained overdentures: A 60-month follow-up of a randomized clinical trial

AIM

The purpose of this observational, post-trial follow-up study was to evaluate 60-month outcomes of a randomized controlled clinical trial that compared immediately and delayed loaded two unsplinted implants, supporting a locator-retained mandibular overdenture.

MATERIALS AND METHODS

Patients from a randomized controlled clinical trial, treated with either immediate or delayed loading of two implants, supporting a locator-retained mandibular overdenture, were recalled for 60-month evaluation. Patients underwent a clinical and radiographic examination to evaluate the peri-implant soft tissue parameters and bone. Prosthetic maintenance needs and complications were also recorded.

RESULTS

Twenty three of the 30 patients were available for the 60-month follow-up. The mean radiographic bone level change measured using standardized periapical radiographs from baseline to 60 months was 0.89 mm (±0.74) and 0.18 (±0.41) for delayed loading and immediate loading groups, respectively. A statistically significant difference was observed at 60 months with a smaller radiographic bone level change in the immediate loading group. No implants were lost between 12 and 60 months. At 60 months, per-protocol implant survival rate was 100% for both the groups. No difference was found in the peri-implant soft tissue parameters and prosthetic needs between the groups.

CONCLUSION

Both immediately and delayed loaded implants supporting a locator-retained mandibular overdenture showed similar clinical outcomes.

Five-year prospective study on conometric retention for complete fixed prostheses

PURPOSE

To evaluate the reliability of a conometric system for fixed retention of complete prostheses (CPs) on four implants after 5 years of function.

MATERIALS AND METHODS

Twenty-five patients with a completely edentulous mandible received four implants supporting a CP. A total of 100 implants were immediately loaded with CPs on conometric abutments. A follow-up of 5 years was observed for each patient. Outcome measures were prosthesis and implant success, complications, probing pocket depth changes, marginal bleeding and plaque changes, and patient satisfaction.

RESULTS

One patient dropped-out. In total, 96 implants supporting the 24 CPs completed the follow-up examination at 5 years. No implant failed. Two framework fractures occurred after 4 and 5 years of function. No loss of retention was recorded for the CPs. Mucositis was recorded for two implants after 1 year of prostheses function for two patients, for one implant after 3 years and for two implants after 4 years in different patients and successfully treated with interceptive supportive therapy. No significant differences were found between Plaque Index (PI) at baseline and after 2 years (P = 1.0); similar findings were calculated between PI at baseline and after 5 years (P = 0.6) of function. At baseline, after 2 and after 5 years, respectively, 69%, 64% and 56% of implants showed a PI of 0; 31%, 36% and 44% of implants showed a PI between 1 and 3. Modify Bleeding Index (MBI) was not significantly different both between baseline and after 2 years of function (P = 1.0) and between baseline and 5 years of function (P = 0.5). At baseline, after 2 and after 5 years, respectively, 69%, 65% and 61% of implants showed a MBI of 0; 27%, 28% and 29% of implants showed a MBI of 1; and 4%, 7% and 10% of implants showed a MBI of 2. The mean probing pocket depth was 1.2 ± 0.4 mm at baseline, 1.2 ± 0.4 mm after 2 years and 1.4 ± 0.5 mm after 5 years of function. The differences were not statistically significant between baseline and 2 years (P = 1.0) and between baseline and 5 years (P = 0.1). From the patient satisfaction questionnaire, 85% percent of patients were satisfied from both aesthetic and functional points of view after 5 years of conometric prostheses function.

CONCLUSIONS

The present implant-supported conometric retention system can be used to give fixed retention to a CP supported by four implants. An adequate metal framework should be provided to the definitive restoration in order to avoid fractures in the long term.

A controlled prospective clinical study

The rehabilitation of the edentulous mandible with implant-supported overdentures is an established clinical procedure but immediate loading of implants supporting mandibular overdentures has not been equally documented.

AIM

The aim of this prospective clinical study was to evaluate the rehabilitation of the edentulous mandible with immediate loading and implant-supported overdentures.

MATERIALS AND METHODS

10 patients were restored with immediate loading of the implants and 5 with delayed loading. The treatment planning included placement of four implants in the interforaminal area of the mandible. Prefabricated titanium abutments with 4 degrees of conical inclination were fixed on the implants and the telescoping conical caps were connected to the base of the mandibular denture. Bone loss was assessed by comparison of panoramic x-rays at baseline 3, 6, and 36 months by visual observation from clinicians.

RESULTS

A total of 60 implants were restored, 40 with immediate and 20 with delayed loading. The follow-up period ranged from 4 to 10 years with 72 months mean observation time. Prosthetic complications appeared with low frequency and no implant loss occurred during the follow-up period. No statistical significance was observed in the bone loss in the cervical area of the immediate and late loaded implants.

CLINICAL SIGNIFICANCE

The rehabilitation of the edentulous mandible with implant-supported overdentures and telescopic copings is a viable clinical solutions with multiple clinical advantages both for the clinician and the patient. . Immediate loading can be applied in cases where increased initial stability can be achieved. More extended long-term clinical studies with increased number of patients and implants are needed, however, to verify the efficacy of the treatment method.

Ten-year follow-up of dental implants used for immediate loading in the edentulous mandible: A prospective clinical study

PURPOSE

The purpose of this study is to evaluate the 10-year outcome of 25 patients with immediate loading in the edentulous mandible.

MATERIAL AND METHODS

Twenty-five patients were consecutively treated with 5 immediately loaded fluoride-modified implants in the edentulous mandible. Implant survival and bone loss were evaluated by an external researcher comparing digital periapical radiographs taken during recall visits with baseline (at implant insertion). Statistical descriptive analysis and nonparametric tests were performed using SPSS v23, multilevel analysis was performed by means of R version 3.1.0. to identify risk factors for bone loss.

RESULTS

Twenty-one patients (8 males, 13 females, mean age 68.4, range 49-84) responded to the 10-year recall invitation. No implants were lost during follow-up, resulting in a 100% survival rate. After 10 years, bleeding on probing and plaque were present at 49.5% and 67.6% of the sites, respectively. The mean pocket probing depth was 3.77 mm (SD 0.73, range 3.0-6.83). Bone loss on implant level after 3, 12, 24, and 120 months was 0.16 mm (SD 0.33, range 0-1.75), 0.14 mm (SD 0.24, range 0-1.05), 0.17 mm (SD 0.27, range 0-1.5), and 0.49 mm (SD 1.08, range 0-7.8). Five implants were identified with or at risk for progressive bone loss. Forty-seven percent of the implants did not show any bone loss after 10 years in function and 87% lost less than 1 mm. Multilevel statistical analysis identified 2-year bone loss as a predictor for bone loss after 10 years of function.

CONCLUSION

Immediate loading of 5 fluoride-modified dental implants with a fixed prosthetic rehabilitation is a predictable and reliable treatment in the edentulous mandible, based on a 100% implant survival and limited peri-implant bone loss. Implants used for immediate loading in the edentulous mandible who are showing early bone loss may be at higher risk to develop peri-implantitis.

The patient general satisfaction of mandibular single-implant overdentures and conventional complete dentures: Study protocol for a randomized crossover trial

BACKGROUND

Mandibular overdentures retained by a single implant placed in the midline of edentulous mandible have been reported to be more comfortable and function better than complete dentures. Although single-implant overdentures are still more costly than conventional complete dentures, there are a few studies which investigated whether mandibular single-implant overdentures are superior to complete dentures when patient general satisfaction is compared. The aim of this study is to assess patient general satisfaction with mandibular single-implant overdentures and complete dentures.

METHODS

This study is a randomized crossover trial to compare mandibular single-implant overdentures and complete dentures in edentulous individuals. Participant recruitment is ongoing at the time of this submission. Twenty-two participants will be recruited. New mandibular complete dentures will be fabricated. A single implant will be placed in the midline of the edentulous mandible. The mucosal surface of the complete denture around the implant will be relieved for 3 months. The participants will then be randomly allocated into 2 groups according to the order of the interventions; group 1 will receive single-implant overdentures first and will wear them for 2 months, followed by complete dentures for 2 months. Group 2 will receive the same treatments in a reverse order. After experiencing the 2 interventions, the participants will choose one of the mandibular prostheses, and yearly follow-up visits are planned for 5 years. The primary outcome of this trial is patient ratings of general satisfaction on 100 mm visual analog scales. Assessments of the prostheses and oral health-related quality of life will also be recorded as patient-reported outcomes. The secondary outcomes are cost and time for treatment. Masticatory efficiency and cognitive capacity will also be recorded. Furthermore, qualitative research will be performed to investigate the factors associated with success of these mandibular denture types. Clinical outcomes, such as implant survival rate, marginal bone loss, and prosthodontic complications, will also be recorded.

DISCUSSION

The results of this randomized crossover trial will clarify whether mandibular single implants and overdentures for edentulous individuals provide better patient general satisfaction when compared to conventional complete dentures.

TRIAL REGISTRATION

This clinical trial was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN000017883).

Use of the MatrixWAVE™ system with dentures to establish maxillomandibular fixation in edentulous patients

Various methods have been described to establish maxillomandibular fixation in the treatment of fractures of atrophic, edentulous mandibles. We used the Synthes MatrixWAVE™ system (DePuy Synthes) in combination with dentures in two patients with fractured, edentulous, atrophic mandibles. Fixation was maintained for fractures that were not amenable to, or did not require, open reduction and internal fixation, and the mandibles were both well-healed and had good function at the end of treatment.

One-year clinical outcomes of locking taper Equator attachments retaining mandibular overdentures to narrow diameter implants

BACKGROUND

Narrow diameter implants (NDI) are recommended to retain mandibular overdentures (MOs) in cases of limited bone thickness. It is necessary to evaluate the clinical behavior of NDI as MO retainers connected to a new screwless locking taper abutments, their predictability and maintenance problems.

OBJECTIVES

To evaluate the peri-implant tissue behavior around NDI and the performance of locking taper stud abutments as MO retainers.

METHODOLOGY

Thirty patients (average age of 67.5 years) received 2 NDI implants (2.9 × 10 mm) loaded after 12 weeks using Equator stud attachments. The plaque index (PI), calculus index (CI), gingival index (GI), probing depth (PD), bleeding on probing (BOP), and implant stability quotient (ISQ) were monitored during osseointegration at 0, 4, 8, and 12 weeks and postloading at 24, 48, and 60 weeks. The marginal bone level (MBL) and bone level changes (BLC) were determined at baseline and 60 weeks.

RESULTS

The cumulative success rate was 83.3%. The PI oscillated in the first 24 weeks and decreased from 48 weeks onward, while the CI score showed significantly higher values at week 8 (22%). The GI also peaked at week 8 (18.6%) and decreased from week 12 onward. The PD decreased gradually over time, but no significant differences were found between weeks 8 and 12. The ISQ decreased significantly between 0 and 12 weeks. After MO loading, the ISQ values increased linearly and significantly between 12 and 24, 24 and 48, and 48 and 60 weeks and reached values similar to the primary stability after 60 weeks [56.1(42.0-65.3)]. No significant MBL was observed at 60 weeks, with an average BLC of -0.06 ± 0.64 mm.

CONCLUSION

NDI connected to locking taper Equator attachments showed a stable clinical behavior as an MO retainer for edentulous patients with clinical mandibular atrophy.

A Qualitative Study on Patients' Perceptions of Two Types of Attachments for Implant Overdentures

The aim of this qualitative study was to gain a deeper understanding of patient perceptions of wearing implant-retained overdentures with ball-shaped or cylindrical attachment systems. Twenty-two wearers of implant-supported overdentures participated in this qualitative study based on a randomized crossover clinical trial that aimed to compare a cylindrical attachment and a ball attachment. In phase I of the study, group A experienced ball attachments (n = 11) and group B Locator attachments (n = 11) for 1 year. Afterward, in phase II, the attachments were changed; group A received Locator attachments and group B received ball attachments. One week after the attachment's replacement, semistructured individual interviews were conducted. All interviews were audiotaped and transcribed. The analysis was guided by thematic content analysis. Most of the patients from both groups preferred the attachment they received in phase II, regardless the type. A major theme raised by the participants to justify their preference between the attachment types was prosthesis retention/stability, sometimes considered as a positive and other times as a negative factor. Other themes were also explored: oral function, pain, hygiene, previous experiences, confidence on the dentist's work, and esthetic. Aspects related to the retention/stability of the overdentures are the main concerns associated with the perceptions of most patients treated with implant overdentures regardless of the type of attachment. Adequate retention level should be identified and adjusted on an individual basis and maintained overtime as possible. Therefore, follow-up appointments should be planned for readjustment of the attachment's retention. Overretention should be avoided.

Cost minimization analysis of a long-term randomized clinical trial of patients treated with immediately loaded implant-supported fixed prosthesis

PURPOSE

To document the long-term costs from a randomized controlled clinical trial (RCT) on edentulous patients treated with mandibular 4-implant-supported fixed prosthesis and two loading protocols.

METHODS

Taking the perspective of the individual patient, costs associated with treatment, complications, and patients' time from 18 patients who received an immediate-loading protocol and 21 patients treated with a conventional loading protocol were compared over 10 years of observation. All costs are in Canadian dollars and discounted to the RCT base year of 2006 at a rate of 1.5%.

RESULTS

The complication rate in both arms was similar and relatively low. No statistically significant difference was observed in the total cost and discounted total cost, along with its five comprising parameters between the two arms.

CONCLUSIONS

Over the 10-year time frame, the immediate loading of dental implants with mandibular fixed prosthesis proved to cost similar to the conventional loading protocol, underscoring the feasibility and reliability of this protocol from the patient's perspective. (REB protocol reference # 33395).

Evaluation of complication rates and vertical bone gain after guided bone regeneration with non-resorbable membranes versus titanium meshes and resorbable membranes. A randomized clinical trial

Background

The partial edentulous posterior mandible is often a challenge area that requires a bone reconstructive surgery for implants placement.

Purpose

This RCT was aimed to evaluate complications rate and vertical bone gain after Guided Bone Regeneration (GBR) with dense non‐resorbable d‐PTFE titanium‐reinforced membranes (Group A) versus titanium meshes covered by cross‐linked collagen membranes (Group B).

Material and Methods

40 partially edentulous patients with atrophic posterior mandible, were randomly divided into two study group: 20 patients were treated with one stage GBR by means of non‐resorbable d‐PTFE titanium‐reinforced membranes (Group A); and 20 patients, by means of titanium mesh covered by cross‐linked collagen membranes (Group B). All complications were recorded, distinguishing between “surgical” and “healing” and between “minor” or “major.”. Primary implants stability and vertical bone gain were also evaluated.

Results

In the group A, surgical and healing complication rates were 5.0% and 15.0%, respectively. In the group B, surgical and healing complication rates were 15.8% and 21.1%, respectively. No significant differences between two study group were observed regarding complications rate implant stability and vertical bone gain.

Conclusions

Both GBR approaches for the restoration of atrophic posterior mandible achieved similar results regarding complications, vertical bone gain and implant stability.

Immediate and delayed loading of two-piece reduced-diameter implants with locator-analog attachments in edentulous mandibles: One-year results from a randomized clinical trial examining clinical outcome and patient expectation

BACKGROUND

Prosthetic management of thin alveolar ridges in the edentulous mandibles of elderly patients, especially the time of loading, the number of implants needed, and patient expectations and perception, is a challenge in implant dentistry.

PURPOSE

Survival of conventionally and immediately loaded 2-piece reduced-diameter implants in the interforaminal region of the edentulous mandible supporting locator-analog attachments was evaluated. Prosthetic complications and peri-implant hygiene were also studied, and patient expectation and subjective evaluation of the treatment were documented.

MATERIAL AND METHODS

Twenty-five patients with adapted complete dentures received 4 reduced-diameter implants. All anterior implants were immediately loaded. Three months later, patients were allocated by randomization to 1 of 2 treatment groups: 2 locator-analog attachments on the anterior implants (Group A); or 4 locator-analog attachments (Group B). After another 3 months patient allocation was changed (crossover design) for the next 3 months. Questionnaires with Likert scales and numeric rating scales were used to assess patients' expectations and subjective overdenture-related variables, respectively.

RESULTS

One implant was lost in the immediate-loading group. Survival was 98% and 100% for immediate and delayed loading, respectively. During 12-month observation, 8 complications required aftercare. At the beginning of treatment, patients' expectations were highly positive. Subjective assessment of overdenture-related variables 3 months after immediate loading of 2 implants revealed a statistically significant improvement for most of the variables studied; this was maintained 1 year later. In the subjective assessments, there were no statistically significant differences between Groups A and B.

CONCLUSION

Immediate loading of reduced-diameter implants supporting locator-analog attachments resulted in high implant survival, few prosthetic complications, good oral hygiene, and improvement of subjective denture perception in the short-term. It might be a promising treatment option, especially for elderly patients with a narrow mandibular ridge.

Implant Stability Quotients of Osteotome Bone Expansion and Conventional Drilling Technique for 4.1 mm Diameter Implant at Posterior Mandible

BACKGROUND

Clinical conclusions in studying the stability and osseointegration of mandibular implants positioned using the bone expansion techniques are conflicting and limited.

PURPOSE

The objective was to examine the implant stability quotient (ISQ) values of mandibular posterior dental implants with 4.1 mm diameter that inserted with osteotome bone expansion technique versus conventional drilling technique during a 12-week observation period.

MATERIALS AND METHODS

Twenty-four implants with 4.1mm diameter in 18 patients were included. Twelve implants in 10 patients were positioned using osteotome bone expansion technique, and 12 fixtures in 9 patients were installed using the conventional drilling technique. The ISQ values of a 3.3 mm diameter implant was measured at recipient sites (ISQ_b ) before final drilling or expansion technique to standardize the increased ISQ value of 4.1 mm diameter implants. The ISQ values at Weeks 0, 1, 2, 3, 4, 6, 8, 10, and 12 post-surgery were recorded. Data were analyzed by Wilcoxon rank sum test, repeated measure ANOVA, and Fisher Lest Significant Difference test.

RESULTS

Calibrated according to a 3.3-mm-diameter implant, bone expansion technique was adopted for the sites with ISQ≦65 bone density, and the areas with ISQ >65 bone condition were treated with conventional drilling technique (p =.038). Both groups presented a similar healing pattern and a comparable ISQ reading from Week 0 to Week 12 (p > .05) for 4.1 mm diameter implants. However, bone expansion technique could enhance more stability when the ISQ values were calibrated by 3.3 mm diameter implant (p < .05).

CONCLUSIONS

Bone expansion technique substantially increased more ISQ values from primary stability and achieved comparable primary and secondary stabilities with the conventional technique. Both groups reached a stability plateaus at Week 10.

Mandibular Full-Arch Fixed Prostheses Supported on 4 Implants with Either Axial Or Tilted Distal Implants: A 3-Year Prospective Study

PURPOSE

This prospective study evaluated the clinical and radiographic outcome of distally cantilevered 4-implant-supported fixed mandibular prostheses (4-ISFMP) with distal implants either in axial or distally tilted direction.

MATERIAL AND METHODS

Forty-one mandibulary edentulous patients received acrylic veneered 4-ISFMP with casted framework. Based on distal implant placement direction patients were assigned to 2 groups: 21 patients with four (2 anterior/2 posterior) axial implants (axial-group I) and 20 patients with 2 anterior axial/2 distal tilted implants (tilted-group II). Patients were prospectively followed for 3 years by annual examinations of implants and prosthetic survival rates including assessment for biological and mechanical complications. Additionally, peri-implant marginal bone resorption [MBR], pocket depth [PD], plaque index [PI], bleeding index [BI] and gingival index [GI], and calculus index [CI] were evaluated at each annual follow-up.

RESULTS

37/41 patients (19 axial-group I, 18 tilted-group II) and 148/164 implants were followed at the 1-, 2-, and 3-year evaluation (dropout rate: 11.8%) presenting no implant and denture loss (100% survival). The overall, MBR at year 1, 2, and 3 was 1.11 ± 0.4 mm, 1.26 ± 0.42 mm, and 1.40 ± 0.41 mm, respectively, representing a significant (p < .001) continuing time depending annual reduction. MBR and PD did not differ between anterior and posterior regions in both groups or for anterior and posterior regions between the groups. PI and CI were significantly (p < .001) higher for implants in anterior regions than for posterior regions in both groups. Moreover, posterior implant regions showed significantly (p < .001) higher PI and CI for axial-group I than for tilted-group II over time. Biological and mechanical complications as well as GI and BI did not differ between the groups over a 3-year follow-up period.

CONCLUSION

For clinical implant and prosthesis outcome no statistical significant mean differences were noted for distally cantilevered 4-ISFMP supported by distal implants placed in tilted or axial direction.

Loading protocols and implant supported restorations proposed for the rehabilitation of partially and fully edentulous jaws. Camlog Foundation Consensus Report

OBJECTIVES

The aim of this consensus meeting was to assess whether immediate loading protocols achieve comparable clinical outcomes when compared to conventional loading protocols depending on the type of prosthetic restoration. In addition post-loading implant loss for implant supported prostheses in edentulous jaws was analyzed regarding a potential impact of implant location (maxilla vs. mandible), implant number per patient, type of prosthesis (removable vs. fixed), and type of attachment system (screw-retained, ball vs. bar vs. telescopic crown).

MATERIAL AND METHODS

Two comprehensive systematic reviews were prepared in advance of the meeting. Consensus statements, practical recommendations, and implications for future research were based on within group as well as plenary scrutinization and discussions of these systematic reviews.

RESULTS

The survival rates are high for immediate loaded and conventional loaded implants, but immediate loading may impose a greater risk for implant failure. The estimated implant loss rate is influenced by the implant location, type of restoration, and implant number.

CONCLUSIONS

Consistent reporting of clinical studies is necessary and high-quality studies are needed to confirm the present results.

A systematic review and meta-analysis of removable and fixed implant-supported prostheses in edentulous jaws: post-loading implant loss

Objectives

The aim of this systematic review was to analyze post‐loading implant loss for implant‐supported prostheses in edentulous jaws, regarding a potential impact of implant location (maxilla vs. mandible), implant number per patient, type of prosthesis (removable vs. fixed), and type of attachment system (screw‐retained, ball vs. bar vs. telescopic crown).

Material and methods

A systematic literature search for randomized‐controlled trials (RCTs) or prospective studies was conducted within PubMed, Cochrane Library, and Embase. Quality assessment of the included studies was carried out, and the review was structured according to PRISMA. Implant loss and corresponding 3‐ and 5‐year survival rates were estimated by means of a Poisson regression model with total exposure time as offset.

Results

After title, abstract, and full‐text screening, 54 studies were included for qualitative analyses. Estimated 5‐year survival rates of implants were 97.9% [95% CI 97.4; 98.4] in the maxilla and 98.9% [95% CI 98.7; 99.1] in the mandible. Corresponding implant loss rates per 100 implant years were significantly higher in the maxilla (0.42 [95% CI 0.33; 0.53] vs. 0.22 [95% CI 0.17; 0.27]; P = 0.0001). Implant loss rates for fixed restorations were significantly lower compared to removable restorations (0.23 [95% CI 0.18; 0.29] vs. 0.35 [95% CI 0.28; 0.44]; P = 0.0148). Four implants and a fixed restoration in the mandible resulted in significantly higher implant loss rates compared to five or more implants with a fixed restoration. The analysis of one implant and a mandibular overdenture also revealed higher implant loss rates than an overdenture on two implants. The same (lower implant number = higher implant loss rate) applied when comparing 2 vs. 4 implants and a mandibular overdenture. Implant loss rates for maxillary overdentures on <4 implants were significantly higher than for four implants (7.22 [95% CI 5.41; 9.64] vs. 2.31 [1.56; 3.42]; P < 0.0001).

Conclusions

Implant location, type of restoration, and implant number do have an influence on the estimated implant loss rate. Consistent reporting of clinical studies is necessary and high‐quality studies are needed to confirm the present results.

Single nucleotide polymorphisms in HIF-1α gene and residual ridge resorption (RRR) of mandible in Korean population

Tooth extraction is a routine surgical procedure in dental treatment. As a wound healing process after tooth extraction, a saddle-shaped residual ridge forms due to bone formation in the extraction socket and localized bone resorption on the external surface of the jawbone. The residual ridge is subjected to continuous bone resorption with substantial differences among individuals. In some cases, it results in excessive bone atrophy, which complicates dental restorative treatment. This unique oral wound healing process may be influenced by factors that are specific to oral tissue. HIF expression is different in oral wound healing compared to that of skin wounds. The objective of this study was to examine a genetic association between SNP of the HIF-1α gene, which is known to have high genetic diversity, and the residual ridge resorption (RRR). Two hundred and two Korean subjects (70.80  ±  9.40 years) with partially or completely edentulous mandible were recruited, and edentulous mandibular bone height was measured following the protocol of the American College of Prosthodontists. The HIF-1α allele was directly sequenced in 24 subjects resulting in the variants over 5% frequency in 95% likelihood, whereas tag-SNPs were selected to perform analysis for the remaining population. Student's t-test and ANOVA were used for statistical analysis to examine the association between the SNPs and the RRR. Four novel variants were discovered, and a minor allele of rs11549467 was associated with the RRR of the subjects (p = 0.028). rs11549467 increases HIF-1α transactivity, enhancing angiogenesis and increasing new vessel formation. Thus, rs11549467 may play an important role in the disturbed bone remodeling balance resulting in RRR. Results of this study may be useful in developing novel genetic diagnostic tests and identifying Koreans susceptible to developing excessive jawbone atrophy after dental extraction. Most importantly, early screening using genetic information will rescue susceptible patients from the vulnerable situation of excessive jawbone atrophy where no effective prosthetic treatment is available.

Decision-making algorithm in treatment of the atrophic mandible fractures

AIM

Closed treatment of atrophic mandible fractures often results in malunion, pseudoarthrosis and pain. Open reduction and rigid internal fixation (ORIF) is still indicated for displaced atrophic mandible fractures. The Authors report a treatment protocol that allows to gain the best results using reconstruction plates, autologous bone grafting and free fibula flap reconstruction when necessary.

METHODS

Retrospective analysis of 15 patients with atrophic mandible fractures who underwent treatment between 2007 and 2011. 7 cases did not receive any treatment because of their general condition, while the others 8 were surgically managed by external approach. In all cases load-bearing osteosynthesis plates with locking screws were used; in 2 of them contextual bone grafts were performed; in 1 case mandible reconstruction needed harvesting a free fibula flap.

RESULTS

In 6 out of 8 cases complete functional and morphological restoration were obtained without any major complication. In 1 case suppurative infection and necrosis of the bone graft occurred, which made necessary its removing, leaving in situ only the reconstruction plate. In another case, during the first year after surgical treatment, atrophic mandible resorption occurred from one angle to the other, resulting in loss of the anchoring reconstruction plate.

CONCLUSIONS

ORIF is the gold standard procedure for the of atrophic mandible fractures, because it guarantees best morpho-functional outcomes and predictability. Nevertheless the Authors suggest contextual bone grafting in case of substance loss, or a poor quality bone or for dental implant surgery and free fibula flap in selected cases.

Technique to Obtain a Predictable Aesthetic Result through Appropriate Placement of the Prosthesis/Soft Tissue Junction in the Edentulous Patient with a Gingival Smile

BACKGROUND

Treating the edentulous patient with a gingival smile requires securing the prosthesis/soft tissue junction (PSTJ) under the upper lip.

PURPOSE

To present a simple method that helps achieve a predictable aesthetic result when alveoplasty of the anterior maxilla is needed to place implants apical to the presurgical position of the alveolar ridge.

MATERIALS AND METHODS

The maximum smile line of the patient is recorded and carved on a thin silicone bite impression as a soft tissue landmark. During the three-dimensional radiographic examination, the patient wears the silicone guide loaded with radiopaque markers. The NobelClinician® software is then used to bring the hard and soft tissue landmarks together in a single reading. Using the software, a line is drawn 5 mm apical to the smile line; it dictates the position of the crestal ridge to be reached following the alveoplasty. Subsequently, the simulated implant position and the simulated residual bone height following alveoplasty can be simultaneously evaluated on each transverse section.

RESULTS

An alveoplasty of the anterior maxilla was performed as simulated on the software, and implants were placed accordingly. The PSTJ was always under the upper lip, even during maximum smile events. The aesthetic result was, therefore, fully satisfactory.

CONCLUSION

This simple method permits the placement of the PSTJ under the upper lip with a predictable outcome; it ensures a reliable aesthetic result for the edentulous patient with a gingival smile.

Immediate Loading of Two Dental Implants, in Edentulous Mandibles, with Locator® Attachments or Dolder® Bars: First Results from a Prospective Randomized Clinical Study

OBJECTIVE

The study aims to evaluate survival and the incidence of complications for pairs of implants placed in the frontal area of edentulous mandibles and immediately loaded with either bar or Locator® (Zest Anchors LLC, Escondido, CA, USA) attachments.

MATERIAL AND METHODS

Forty-six patients (mean age 69.4 years; 73.9% male) with edentulous mandibles each received two immediately loaded implants in the interforaminal area of the symphysis. Immediately after implant placement, Dolder® bar (Sub-Tec Wirobond; BEGO Implant Systems GmbH & Co. KG, Bremen, Germany) or Locator® attachments, allocated randomly, were attached, and both clips and a framework were incorporated into the denture by the dental technician. The implants were loaded within 72 hours.

RESULTS

During a mean observation period of 6 months (maximum 24 months, SD 0.43) eight implants in five patients were lost. Survival was 93.5% for the Locator® group and 89.1% for the bar group. Estimated cumulative survival after 1 year of function was 93.4% for the Locator® group and 87.1% for the bar group. During the observation period, 12 prosthetic complications required aftercare. No superstructure was lost or had to be remade for prosthetic reasons, but five dentures had to be removed or reworked after implant failure. Survival of the original dentures was, therefore, 95.7% for the Locator® group and 93.5% for the bar group.

CONCLUSION

Within the limitations of this study, immediate loading of two implants in the edentulous mandible with either Locator® or bar attachments did hardly differ. Ease of repair and cleaning, in particular, might be arguments for choosing the single attachment system.

Implant and prosthodontic survival rates with implant fixed complete dental prostheses in the edentulous mandible after at least 5 years: a systematic review

BACKGROUND

The treatment of mandibular edentulism with implant fixed complete dental prostheses (IFCDPs) is a routinely used treatment option.

PURPOSE

The study aims to report the implant and prosthodontic survival rates associated with IFCDPs for the edentulous mandible after an observation period of a minimum 5 years.

MATERIALS AND METHODS

An electronic MEDLINE/PubMED search was conducted to identify randomized controlled clinical trials and prospective studies with IFCDPs for the edentulous mandible. Clinical studies with at least 5-year follow-up were selected. Pooled data were statistically analyzed and cumulative implant- and prosthesis survival rates were calculated by meta-analysis, regression, and chi-square statistics. Implant-related and prosthesis-related factors were identified and their impact on survival rates was assessed.

RESULTS

Seventeen prospective studies, including 501 patients and 2,827 implants, were selected for meta-analysis. The majority of the implants (88.5% of all placed implants) had been placed in the interforaminal area. Cumulative implant survival rates for rough surface ranged from 98.42% (95% confidence interval [CI]: 97.98-98.86) (5 years) to 96.86% (95% CI: 96.00-97.73) (10 years); smooth surface implant survival rates ranged from 98.93% (95% CI: 98.38-99.49) (5 years) to 97.88% (95% CI: 96.78-98.98) (10 years). The prosthodontic survival rates for 1-piece IFCDPs ranged from 98.61% (95% CI: 97.80-99.43) (5 years) to 97.25% (95% CI: 95.66-98.86) (10 years).

CONCLUSION

Treatment with mandibular IFCDPs yields high implant and prosthodontic survival rates (more than 96% after 10 years). Rough surface implants exhibited cumulative survival rates similar to the smooth surface ones (p > .05) in the edentulous mandible. The number of supporting implants and the antero-posterior implant distribution had no influence (p > .05) on the implant survival rate. The prosthetic design and veneering material, the retention type, and the loading protocol (delayed, early, and immediate) had no influence (p > .05) on the prosthodontic survival rates.

Overdentures in the edentulous mandible supported by implants and retained by a Dolder bar: a 5-year prospective study

PURPOSE

This prospective study was performed to evaluate the outcomes of XiVE® S plus implants (Dentsply Friadent, Mannheim, Germany) following conventional restoration with bar structures and overdentures in the edentulous mandible.

MATERIALS AND METHODS

A total of 39 patients were treated with four interforaminal implants (n = 156) splinted by a Dolder bar. Overdentures were attached to the bars after 3 months of healing. As primary outcome measures, clinical and radiological parameters were evaluated at the time of implant placement (baseline) and once a year (1, 2, 3, 4, 5 years) after functional loading. Secondary outcome measures included (i) primary stability and surgical complications, as well as (ii) Periotest® (Medizintechnik Gulden, Modautal, Germany) values, implant survival, and prosthetic complications at baseline and follow-up.

RESULTS

A total of 156 implants were placed. The vast majority (n = 149) were tightened to >30 Ncm, while torques in the range of 20-30 Ncm were obtained in the remaining cases (n = 7). Mean crestal bone levels around the implants were 0.41 mm at baseline and 1.04/1.20/1.34/1.45/1.44 mm after 1/2/3/4/5 years respectively. The mean values of the plaque, calculus, bleeding, and mucosal indices remained low throughout this period. The reported follow-up periods involved one implant loss after 3 months (survival rate: 99.4%) and one implant failure after 4 years (success rate: 98.4%). Prosthetic complications included factures of bars (n = 3) and denture teeth (n = 7). Prosthetic survival was 100%.

CONCLUSIONS

Dolder bars to restore oral implants in the edentulous mandible appear to offer a high rate of implant survival, good stability of the peri-implant tissue, and a low rate of prosthetic complications.