Radiographic evaluation of the distance between the restoration margin and the alveolar bone crest in dental implant patients: A retrospective study

OBJECTIVES

The recently introduced Implant Disease Risk Assessment (IDRA) identifies a restoration margin-alveolar bone crest (RM-AC) distance of less than 1.5 mm as a key risk factor for peri‑implant disease among eight major risk factors. This study evaluated the impact of the RM-AC distance on marginal bone loss (MBL) through radiographic analysis.

METHODS

This retrospective cross-sectional study included 77 partially edentulous patients (39 females and 38 males, aged 22 to 76 years) with 202 platform-switched conical connection implants, cement-retained, implant-supported fixed restorations, and bone-level implants placed between 2016 and 2021. Dental implants were followed for least 6 to 36 months at follow up functional loading. Study participants were categorized into Group A (RM-AC distance ≤ 1.5 mm, n = 69) and Group B (RM-AC distance > 1.5 mm, n = 133). Twelve patients in Group B and five patients in Group A had no history of periodontal disease. The MBL was measured radiographically from the most coronal point of the implant shoulder to the alveolar bone, and the RM-AC distance was measured from the restoration margin to the alveolar crest. Multinomial logistic regression analysis was used for statistical evaluation.

RESULTS

The incidence of MBL in Group A was statistically significant and 3.42 times higher than that in Group B. The rate of MBL in periodontitis Stage 4 was found to be 26.31 times higher than that in periodontitis Stage 2. The incidence of MBL was 6.097 and 5.02 times higher with increasing implant diameter and length, respectively.

CONCLUSION

This study conclusively demonstrates that RM-AC distance ≤ 1.5 significantly increases the risk of MBL, particularly in patients with a history of periodontal disease.

CLINICAL SIGNIFICANCE

This study highlights the critical role of maintaining an RM-AC distance greater than 1.5 mm in the prevention of MBL, particularly in patients with a history of periodontal disease. Since implant diameter and length have a significant impact on the risk of MBL, it emphasizes that implant demographics should also be carefully evaluated.

Undesirable course of an oral implant rehabilitation in a patient with a long history of bulimia nervosa: case report and review of the literature

BACKGROUND

Bulimia nervosa is an eating disorder resulting in an intended weight loss due to decreased food intake, induced vomiting, or hyperactivity, and is observed frequently between 12 and 25 years of age. One of the complications is early tooth loss. Moreover, since bulimia nervosa patients suffer from increased atrophy of the alveolar processes, oral rehabilitation even with short dental implants may be impossible. In these cases, lateralization or transposition of the inferior alveolar nerve (IAN) followed by implant placement can be useful.

CASE PRESENTATION

A 40-year-old woman with a long-lasting history of bulimia nervosa requested a fixed rehabilitation of her partially edentulous mandible. In 2012, a bilateral IAN transposition approach was performed using piezosurgery, and without any postoperative neurosensory alterations. Two years later, bilateral insertion of each two implants was followed by an inflammatory destabilization of the lower left mandible; subsequent to the implant removal, a fracture occurred, and the latter was stabilized by osteosynthesis plates. In 2017, three additional implants were placed, finally providing the patient with a fixed restoration on five implants.

CONCLUSION

Eating disorders may have a tremendous impact on both physical condition and oral health, resulting in early tooth loss and severe bone atrophy. IAN transposition is a viable treatment option to enable installing fixed prostheses via dental implants, but the latter will clearly increase the risk of inflammation and interruption of mandibular continuity. Close clinical and radiologic monitoring is mandatory to adequately respond to complications such as peri-implant mucositis, peri-implantitis, osteomyelitis, or concomitant fractures.

Assessment of Lingual Concavities in Submandibular Fossa Region in Patients requiring Dental Implants-A Cone Beam Computed Tomography Study

AIM

The present study was aimed at assessing the lingual concavities in the submandibular fossa region in patients requiring dental implants with the help of cone beam computed tomography (CBCT).

MATERIALS AND METHODS

The present study included 140 patients who visited the department with the missing mandibular posterior teeth. CBCT images were obtained using planmeca machine. Cross sections of 1 mm of submandibular fossa in the region of 1st and 2nd molar were studied and Type I to III lingual concavities were analyzed by a radiologist.

RESULTS

Type I lingual concavity (< 2 mm) was seen in 23%, type II (2-3 mm) in 62% and Type III (> 3 mm) in 15% of patients. The difference was significant (p < 0.05). Males had slightly higher mean ± S.D value at 1st molar (2.6 mm ± 0.94) and 2nd molar (2.8 mm ± 0.90) on the left side and (2.7 mm ± 0.92) at 1st molar and (2.9 mm ± 0.93) at 2nd molar on the right side. The difference was nonsignificant (p > 0.05). Females had mean ± S.D value at 1st molar (2.3 mm ± 0.90) and (2.5 mm ± 0.92) at 2nd molar on the left side and (2.4 mm ± 0.91) at 1st molar and (2.8 mm ± 0.93) at 2nd molar. The difference was nonsignificant (p > 0.05. The difference between both genders was statistically nonsignificant (p > 0.05).

CONCLUSION

Type I bone is the best for placing an implant. The chances of complications are more in type II and III bone. CBCT provides necessary information before planning implant in the edentulous area.

CLINICAL SIGNIFICANCE

Cone beam computed tomography (CBCT) is the best radiographic aid which is effective in delineating different types of bone in the mandibular posterior region.

Association Between Missing Posterior Teeth and Occurrence of Temporomandibular Joint Condylar Erosion: A Cone Beam Computed Tomography Study

PURPOSE

To determine a possible association between asymptomatic temporomandibular joint (TMJ) condylar erosion and the number of missing posterior teeth and their location, as well as the number of dental quadrants with missing posterior teeth.

MATERIALS AND METHODS

This case-control study involved 210 patients (male to female ratio = 98:112) aged 16-74 years, with 105 asymptomatic patients with TMJ condylar erosion and a control group of 105 patients without TMJ condylar erosion. Cone beam computed tomography images were evaluated to classify the severity of TMJ condylar erosion as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion).

RESULTS

The number of missing posterior teeth (mean ± standard deviation [SD]; 2.7 ± 2.4 vs 0.7 ± 1.2) (P < .001), number of dental quadrants with missing posterior teeth (1.5 ± 1.3 vs 0.6 ± 0.9) (P < .001), and bilateral location of missing posterior teeth (41 ± 39.0 vs 10 ± 9.5) (P < .001) were all significantly higher in patients with erosion than in those without erosion. The condylar erosion grade was significantly associated with the number of missing posterior teeth (odds ratio [OR] = 1.24; P = .006), the number of dental quadrants with missing posterior teeth (OR = 1.36; P = .006), and the bilateral occurrence of missing posterior teeth (OR = 3.03; P = .002).

CONCLUSION

The findings from this study suggest a possible association between TMJ condylar erosion grades and the number of missing posterior teeth, the number of quadrants with missing posterior teeth, and the bilateral occurrence of missing posterior teeth.

Histologic and Histomorphometric Analysis at 26 Months of a Bovine Hydroxyapatite Maxillary Sinus Graft: A Case Report

A variety of biomaterials are used when performing sinus augmentation techniques. Bovine hydroxyapatite (BH) has already been demonstrated to present osteoconductive properties. The aim of this article is to provide a histologic and histomorphometric analysis, at 26 months, of a bone specimen extracted from a BH maxillary sinus graft. Histomorphometric results showed 64.4% bone density and 24.4% biomaterial density. Histologic analysis revealed marked bone formation and high osteoconductive properties in the BH particles, with no associated signs of inflammation. Resorption appeared minimal. BH seems to present high biocompatibility and osteoconductive properties.

Clinical factors in prosthodontic treatment of children with genetic defects

BACKGROUND

Prosthodontic treatment of children with genetic disorders is an area that is rarely examined in the current specialist literature. Few prosthodontists will undertake treatment of such patients, who will more often be referred to an orthodontic specialist. After examining the 4 cases of children with genetic disorders described in this paper, it can be concluded that when a prosthodontist includes a few additional procedures in the treatment process, he or she can successfully help such patients.

OBJECTIVES

The aim of this paper is to indicate the clinical difficulties faced by prosthodontists who undertake prosthodontic rehabilitation of children with genetic disorders.

MATERIAL AND METHODS

The paper is based on data collected during the prosthodontic treatment of 4 children, aged 5-12 years with genetic defects, and analysis of the body of work concerning these defects and their treatment.

RESULTS

Presentation of guidelines for the prosthodontic treatment process and creation of dentures for treated children based on extended procedures.

CONCLUSIONS

A prosthodontist is a crucial person in a team of specialists treating disorders within the face among children with a genetic predisposition. A basic knowledge of orthodontics and psychology facilitates the treatment. Prosthetic restoration in the treatment group does not always require complicated operations. Individualization of the tools for downloading orthodontic impressions, designing denture elements and an increased number of checkups are the additional procedures. For the clinician, the emotional aspect of the treatment is the main impediment. Maintaining a good relationship with a patient and his or her caregivers requires interpersonal skills.

Radiographic Evaluation of Crestal Bone Level in Split-Crest and Immediate Implant Placement: Minimum 5-Year Follow-up

PURPOSE

This study aimed to evaluate the radiographic bone level changes of implants positioned via the split-crest procedure both in the maxilla and mandible at a long-term follow-up.

MATERIALS AND METHODS

Seventy-one patients were retrospectively enrolled in the study. The placement of 137 dental implants was performed in the edentulous premolar or molar region after a split-crest ridge expansion procedure. Implants followed a delayed loading protocol. Intraoral digital radiographs were performed at baseline, upon implant placement, at 70 days (following placement of the provisional prosthesis), and on a yearly basis during followup. Crestal bone levels were evaluated at the baseline, upon provisional prosthesis placement, at 12, 36, and 60 months, and at the long-term follow-up of healing from implant placement.

RESULTS

The patients underwent a mean follow-up of 6.54 ± 1.32 years, from which the implant survival rate was reported at 98.54%. Within the first year from implant placement, a bone loss resulted at a mean value of -1.11 ± 0.44 mm. After almost 3 years from implant placement, a mean bone gain of +0.89 ± 0.39 mm was reported, which was statistically significant compared with 12-month values (P < .05). From this point, bone levels remained stable, reporting similar values over time, with no significant differences (P > .05).

CONCLUSION

A mean vertical bone gain of +0.89 ± 0.39 mm was observed after almost 36 months after implant positioning.

Reconstruction-Based Digital Dental Occlusion of the Partially Edentulous Dentition

Partially edentulous dentition presents a challenging problem for the surgical planning of digital dental occlusion in the field of craniomaxillofacial surgery because of the incorrect maxillomandibular distance caused by missing teeth. We propose an innovative approach called Dental Reconstruction with Symmetrical Teeth (DRST) to achieve accurate dental occlusion for the partially edentulous cases. In this DRST approach, the rigid transformation between two symmetrical teeth existing on the left and right dental model is estimated through probabilistic point registration by matching the two shapes. With the estimated transformation, the partially edentulous space can be virtually filled with the teeth in its symmetrical position. Dental alignment is performed by digital dental occlusion reestablishment algorithm with the reconstructed complete dental model. Satisfactory reconstruction and occlusion results are demonstrated with the synthetic and real partially edentulous models.

An Analysis of Frequency, Morphology, and Locations of Maxillary Sinus Septa Using Cone Beam Computed Tomography

PURPOSE

To evaluate the frequency, morphology, and locations of maxillary sinus septa using cone beam computed tomographic (CBCT) imaging of the entire maxillary sinus and to analyze factors influencing the presence or absence of septa.

MATERIALS AND METHODS

CBCT images of the maxilla taken during a 1-year study period (October 1, 2012, to September 30, 2013) were evaluated for the presence and type of septa as well as the health or pathology of the maxillary sinus. Differences in age, gender, type of dentition, septa location, and sinus pathology with regard to the incidence of sinus septa were analyzed statistically.

RESULTS

The study included 294 maxillary sinuses in 212 patients (126 women and 86 men) with a mean age of 53.8 years. Sinus septa were present in 141 patients (66.5%) and in 166 of 294 sinuses (56.5%). The most common orientation of the septa was coronal (61.8%), 7.6% were oriented axially, and 3.6% were aligned sagittally. Most septa were located on the floor of the maxillary sinus (58.6%), commonly (60.7%) in the region of the first and second molars. The maxillary sinuses were diagnosed in 36.4% of cases as healthy and without thickening of the sinus membrane. Sex was a significant variable in the health of the maxillary sinus; 57.7% of the sinuses in women and 72.3% in men were diagnosed as pathologic.

CONCLUSION

Septa are common anatomical structures and are most often found in the first or second molar region on the floor of the maxillary sinus. To prevent possible complications during sinus floor elevation procedures, a thorough three-dimensional radiographic examination of the sinus prior to surgery is recommended.

Sinus grafting and simultaneous removal of large antral pseudocysts of the maxillary sinus with a micro-invasive intraoral access

Large antral pseudocysts of the maxillary sinus (APCs) may hamper the elevation of the Schneiderian membrane during sinus grafting and may impair osteo-meatal complex patency after sinus augmentation. Therefore, these should be removed prior to or at the time of sinus grafting. This study presents a new technique that combines enucleation of large APCs during sinus grafting via a lateral approach with preservation of the Schneiderian membrane periosteal layer. Twelve patients underwent a sinus graft via lateral approach during the years 2004-2012. Simultaneous APC removal was achieved through a small additional bony access, preserving the integrity of the periosteal layer of the Schneiderian membrane. Nineteen implants were inserted at the time of sinus augmentation or during a second stage. Prosthetic rehabilitation was started at 4-6 months after implant placement. No patient developed surgical complications or APC recurrence. The survival rate of implants and related prostheses was 100% over a mean follow-up of 50 months (range 12-96 months) after completion of the prosthetic restorations. This technique may represent an effective procedure to achieve APC removal at the time of sinus grafting, preserving the integrity of the Schneiderian membrane periosteal layer.

Linear accuracy and reliability of volume data sets acquired by two CBCT-devices and an MSCT using virtual models: a comparative in-vitro study

OBJECTIVE

To discriminate clinically relevant aberrance, the accuracy of linear measurements in three-dimensional (3D) reconstructed datasets was investigated.

MATERIALS AND METHODS

Three partly edentulous human skulls were examined. Landmarks were defined prior to acquisition. Two CBCT-scanners and a Quad-slice CT-scanner were used. Actual distances were physically measured with calipers and defined as a reference. Subsequently, from digital DICOM datasets, 3D virtual models were generated using maximum intensity projections (MIPs). Linear measurements were performed by semi-automated image analysis. Virtual and analogue linear measurements were compared using repeated measurements in a mixed model (p ≤ 0.05).

RESULTS

No significant difference was found among all of the digital measurements when compared to one another, whereas a significant difference was found in matched-pairs analysis between CBCT and calipers (p = 0.032). All digitally acquired data resulted in lower mean values compared to the measurements via calipers. A high level of inter-observer reliability was obtained in the digital measurements (inter-rater correlation = 0.988-0.993).

CONCLUSIONS

The reconstructed datasets led to highly consistent values among linear measurements. Yielding sub-millimeter precision, these modalities are assumed to reflect reality in a clinically irrelevant altered manner. During data acquisition and evaluation, a maximum of precision must be achieved.

Radiographic bone level changes of implant-supported restorations in edentulous and partially dentate patients: 5-year results

PURPOSE

To evaluate and compare crestal bone level changes and peri-implant status of implant-supported reconstructions in edentulous and partially dentate patients after a minimum of 5 years of loading.

MATERIALS AND METHODS

All patients who received a self-tapping implant with a microstructured surface during the years 2003 and 2004 at the Department of Prosthodontics, University of Bern, were included in this study. The implant restorations comprised fixed and removable prostheses for partially and completely edentulous patients. Radiographs were taken immediately after surgery, at impression making, and 1 and 5 years after loading. Crestal bone level (BIC) was measured from the implant shoulder to the first bone contact, and changes were calculated over time (ΔBIC). The associations between pocket depth, bleeding on probing (BOP), and ΔBIC were assessed.

RESULTS

Sixty-one implants were placed in 20 patients (mean age, 62 ± 7 years). At the 5-year follow-up, 19 patients with 58 implants were available. Implant survival was 98.4% (one early failure; one patient died). The average ΔBIC between surgery and 5-year follow-up was 1.5 ± 0.9 mm and 1.1 ± 0.6 mm for edentulous and partially dentate patients, respectively. Most bone resorption (50%, 0.7 mm) occurred during the first 3 months (osseointegration) and within the first year of loading (21%, 0.3 mm). Mean annual bone loss during the 5 years of loading was < 0.12 mm. Mean pocket depth was 2.6 ± 0.7 mm. Seventeen percent of the implant sites displayed BOP; the frequency was significantly higher in women. None of the variables were significantly associated with crestal bone loss.

CONCLUSION

Crestal bone loss after 5 years was within the normal range, without a significant difference between edentulous and partially dentate patients. In the short term, this implant system can be used successfully for various prosthetic indications.

Clinical and radiographic evaluation of narrow-diameter titanium-zirconium implants in unilateral atrophic mandibular distal extensions: a 1-year pilot study

BACKGROUND

The use of endosseous dental implants has led to more sophisticated fxed options when considering treatment of patients with distal extensions. The use of narrow-diameter implants may reduce the necessity for bone augmentation. The mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable.

PURPOSE

The purpose of this study was to evaluate clinically and radiographically the performance of narrow-diameter bone level implants made from titanium-zirconium alloy (TiZr, Roxolid(TM)) in restoring unilateral atrophic mandibular distal extensions with fxed dental prostheses.

MATERIALS AND METHODS

Twenty partially edentulous patients with unilateral atrophic mandibular distal extensions received two 3.3 mm diameter bone level TiZr implants (Straumann AG, Basel, Switzerland). The two implants were restored with 3-units ceramo-metal fxed partial dentures. Standardized clinical and radiographic parameters (survival rate, probing pocket depth and marginal bone loss) were evaluated at the time of the completion of the prosthetic treatment (baseline) and after 3, 6 and 12 months of functional loading. Prosthetic complications were also assessed.

RESULTS

The survival rate for narrow-diameter bone level TiZr implants was 100% after 1 year of functional loading. There were no statistically significant differences between the values of probing pocket depth over the follow-up period. All implants showed less than 1 mm of marginal bone loss at the end of the follow-up period.

CONCLUSION

Within the limitations of this 1-year pilot study, the use of narrow-diameter bone level TiZr implants appears to be predictable in restoring the unilateral atrophic mandibular distal extensions. This type of implants meets established success and survival criteria after 1 year.

Three-dimensional volume change of grafted bone in the maxillary sinus

PURPOSE

The purpose of this study was to evaluate the three-dimensional radiographic changes of 100% anorganic bovine bone xenograft volume in a grafted maxillary sinus, based on a computerized analysis of cone-beam computed tomography (CBCT) scan.

MATERIALS AND METHODS

A maxillary sinus augmentation procedure done with a lateral approach using 100% anorganic bovine bone was performed in 20 patients. A CBCT scan of the grafted area was taken immediately after the procedure (T1) and 8 to 9 months later (T2). CBCT scan data were analyzed with image processing software to evaluate differences in the volume of grafted material between T1 and T2. Residual ridge height and width were also measured at T1.

RESULTS

The mean residual bone height and width at the implant sites was 4.40±0.87 mm and 7.9±2.22 mm, respectively. The mean graft volume was 1,432±539 mm³ and 1,287±498 mm³ at T1 and T2, respectively. A significant difference in graft volume was found between T1 and T2 data by paired t test (P=.01). The mean ratio between the volume at T2 and the volume at T1 was 0.90±0.12, meaning a graft volume contraction of 10%.

CONCLUSION

Within the limits of the present investigation, good stability of anorganic bovine bone graft volume up to 8 months after the grafting procedure was demonstrated. Three-dimensional computed tomographic volumetric assessment seems to be a promising approach to quantify long-term changes in the regenerated area.

Retrospective results of implants for partially edentulous posterior jaws according to time points of early loading

PURPOSE

This study evaluated the survival and success rates and marginal bone loss conditions of early loaded implants in the posterior maxilla and mandible of partially edentulous patients.

MATERIALS AND METHODS

Implants (n = 299) were placed in 105 patients at two research centers. Provisional fixed dental prostheses were provided to the patients between 1 week and 2 months after implant placement. The implants were classified into four groups according to the loading time (1 to 2, 2 to 4, 4 to 6, and 6 to 8 weeks). Periapical radiographs were taken via a parallel imaging technique, and the peri-implant marginal bone level was measured on the radiographic images.

RESULTS

Most implants were lost within 1 month, and one implant was removed at 36 days after loading. The cumulative survival rate of the implants was 97.0%. Implants loaded in the maxilla at 1 to 2 weeks after prosthesis insertion had significantly lower survival rates than any other group (P = .013). There were no significant differences in marginal bone levels among the implant groups classified according to loading time.

CONCLUSIONS

Early loading is a safe and predictable procedure for implant-supported restoration of posterior partial edentulism. However, care must be taken in early loading within 2 weeks after maxillary implant insertion.

Vertical ridge augmentation using sandwich osteotomy: 2 case reports

The placement of dental implants in atrophic jaws is a challenging procedure due to inadequate bone quantity. This anatomic limitation can be overcome by various treatment methods such as onlay bone graft, inlay bone graft (known as sandwich osteotomy), and distraction osteogenesis. Two female patients with complaints of atrophic mandible were included in this study. Both patients were treated with a segmental mandibular sandwich osteotomy with interpositional grafts. This is called a sandwich osteotomy technique because a section of the jaw bone is separated from the main part and a bone graft is inserted between the 2 parts. The postoperative period was uneventful, and sufficient bone gain was obtained in both patients. Sandwich osteotomy is an effective technique to gain vertical bone height in atrophic jaws.

Is the Schneiderian membrane thickness affected by periodontal disease? A cone beam computed tomography-based extended case series

OBJECTIVE

The aim was to assess the thickness of Schneiderian membranes (SM) in patients with advanced periodontal disease.

METHODS

17 dentate patients (DG) scheduled for periodontal surgery on maxillary molars were consecutively recruited and cone beam computed tomographies performed for preoperative diagnosis. Twenty-one patients (EG) requiring cone beam computed tomography-based planning of implant placement in the edentulous posterior maxilla served as controls.

RESULTS

Schneiderian membrane thickness measured from cone beam computed tomography was significantly greater in the dentate group compared to the edentulous group, both in the first (p = 0.028) and second (p < 0.001) molar position. In the dentate group, clinical signs of periodontal destruction (increased probing pocket depth or furcation involvement) were not associated with Schneiderian membrane thickness. Additional findings, such as periapical lesions (p = 0.008), and the distance between root tips and maxillary sinus revealed a significant association (p = 0.036) with Schneiderian membrane thickness.

CONCLUSION

In molar regions with periodontal destruction, Schneiderian membrane thickening occurred, particularly in combination with small bone layers above the root tips or periapical lesions.

Cone beam CT evaluation of maxillary sinus septa prevalence, height, location and morphology in children and an adult population

OBJECTIVE

The purpose of this study was to determine the prevalence, height, location and morphology of maxillary sinus septa in dentate, partially dentate and edentulous adults as well as in mixed dentition children using cone beam computed tomography (CBCT) for maxillary sinus surgical interventions.

SUBJECTS AND METHODS

Five hundred and fifty-four sides in the CBCT scans of 272 patients (30 children and 242 adults) were retrospectively analyzed. The prevalence, location and morphology were assessed in axial, sagittal, cross-sectional and panoramic 3-dimensional images. The height of septa was measured with the angle between the direction of the septum and median palatine suture. The differences among age, localization and measurements were statistically analyzed.

RESULTS

The prevalence of maxillary sinus segments with septa was 58%. There were a total of 13 (3.2%) septa of completely edentulous (CE), 198 (53.9%) septa of edentate and 14 (3.8%) septa of the mixed dentition maxillary segments. The location of septa observed in all study groups demonstrated a greater prevalence (69.1%) in the middle region than in the anterior and posterior regions. No statistically significant differences were observed with regard to gender or age, for septum height (p > 0.05). However, maxillary sinus septa are higher in partially edentulous patients than edentate and CE ones (p < 0.05).

CONCLUSION

Septa of various heights and courses developed in all parts of the maxillary sinus, therefore to prevent possible complications during sinus surgery, extensive evaluation with an appropriate radiographic technique was indispensable.

Influence of semipermanent cement application used in immediately loaded, implant-supported restorations on crestal bone resorption

INTRODUCTION

The paper presents clinical-radiological research on the impact of the new semi-cement luting agent in the immediately loaded implant-supported restoration on alveolar ridge resorption.

MATERIAL AND METHODS

25 patients with a partially edentulous alveolar ridge in the anterior section of the maxilla or mandible were included in the study. The implants were inserted with the application of traditional burs or with a Piezosurgery device supplied by Mectron. Taking into account the method of implant bed preparation, the scientific material was divided into two groups. The implants were loaded immediately with single crown restorations cemented with the Implantlink semi cement application. The following indices were taken into consideration: pocket depth around implant calculated at four measuring points, marginal alveolar bone loss measured using radio-visiography, the 3-degree Wachtel scale of healing of the soft tissue. In addition, the presence and possible width or height of any recession around the implants was measured. The success of the implant treatment was assessed according to the Albrektsson success criteria. The research results were subjected to statistical analysis.

RESULTS

The results of our study revealed no influence of the Implant-link semi cement on the crestal bone level, regardless of the bone bed preparation technique.

Radiographic assessment of findings in the maxillary sinus using cone-beam computed tomography

OBJECTIVES. To assess the presence of anatomic variations and pathology of the maxillary sinus using cone beam computed tomography (CBCT) of the maxilla where pre- implant surgery is planned. MATERIAL AND METHODS. This retrospective study evaluates a sample CBCT scans of 34 dental patients (68 sinuses). CBCT is used to assess maxillary sinus mucosa and outflow and prevalence of septa. The mucosal thickening was measured and the sinus outflow was classified as open or obstructed. RESULTS. Mucosal thickening was found in 48.5%, septa in 20.6% and total opacity in 2.9% of the sinuses. Maxillary sinus outflow was blocked in 26.5% of the scans. Strong association between radiological signs of maxillary sinus ostium blockage and thickened mucosa was observed. CONCLUSIONS. Anatomic variations and lesions of the maxillary sinus were common findings in CBCT examinations of the maxilla required for dental preprosthetic planning. Routine CBCT scans, including maxillary sinus ostium are recommended for risk assessment prior to surgery.

The effect of scan parameters on cone beam CT trabecular bone microstructural measurements of human mandible

The objective of this study was to investigate the effect of different cone beam CT scan parameters on trabecular bone microstructure measurements. A human mandibular cadaver was scanned using a cone beam CT (3D Accuitomo 170; J.Morita, Kyota, Japan). 20 cone beam CT images were obtained using 5 different fields of view (4×4 cm, 6×6 cm, 8×8 cm, 10×10 cm and 10×5 cm), 2 types of rotation steps (180° and 360°) and 2 scanning resolutions (standard and high). Image analysis software was used to assess the trabecular bone microstructural parameters (number, thickness and spacing). All parameters were measured twice by one trained observer. Intraclass correlation coefficients showed high intraobserver repeatability (intraclass correlation coefficient, 0.95–0.97) in all parameters across all tested scan parameters. Trabecular bone microstructural measurements varied significantly, especially in smaller fields of view (p = 0.001). There was no significant difference in the trabecular parameters when using different resolutions (number, p = 0.988; thickness, p = 0.960; spacing, p = 0.831) and rotation steps (number, p = 1.000; thickness, p = 0.954; spacing, p = 0.759). The scan field of view significantly influences the trabecular bone microstructure measurements. Rotation steps (180° or 360°) and resolution (standard or high) selections are not relevant.

Complete transition from failing restorations to implant-supported fixed prostheses in a patient with scleroderma

In a case involving a patient with scleroderma, the authors demonstrate how to treatment plan and sequence the transition from a failing restored dentition to complete implant-supported fixed prostheses with sequential extractions and implant placements. The article also presents surgical and prosthodontic considerations for a complete-mouth implant-supported fixed rehabilitation while achieving optimal esthetics without compromising function in patients with this condition. Sequential treatment provided the patient with fixed provisional restorations during treatment in multiple, short surgical appointments with less psychosocial trauma. This case posed treatment challenges due to limited oral access, unpredictable disease progression, and limited data on the success of treatment with endosseous dental implants in these patients.

Clinical and radiographic evaluation of patients receiving both tooth- and implant-supported prosthodontic treatment after 5 years of function

PURPOSE

The aim of this research was to assess survival and complication rates of tooth- and implant-supported fixed dental prostheses (FDPs) and single crowns (SCs) after 5 years of function in a specific patient population group who underwent comprehensive prosthetic treatment.

MATERIALS AND METHODS

This retrospective study included a convenience sample of 52 patients who met specific inclusion and exclusion criteria and were treated during two specific courses as part of the undergraduate curriculum. The patients' prosthodontic treatment comprised 296 tooth-supported and 37 implant-supported SCs together with 76 tooth-supported and 15 implant-supported FDPs. Pre- and posttreatment clinical examinations included screening for biologic and technical complications, probing pocket depth, bleeding on probing (BoP), and plaque control record (PCR) as well as intraoral radiographs. Information was obtained from the patients about dental hygiene and dental visits, treated complications, and patient satisfaction during the observation period. Descriptive statistics were employed.

RESULTS

Forty-five patients were followed for a mean observation period of 5.26 ± 0.47 years. The survival rates were 99.0% for tooth-supported SCs, 98.7% for tooth-supported FDPs, and 100% for implant-supported FDPs and SCs. Loss of vitality was observed in 2.9% of all abutment teeth deemed to be vital initially. Endodontic complications occurred in 5% and root fracture in 2.5% of nonvital abutment teeth. Caries was found in 0.4% of abutments. No framework or implant fractures were observed, but fracture of the veneering ceramic affected 3.8% of FDPs. The mean BoP was 21.5% ± 9.9%, and the mean PCR was 22.8% ± 16.5%. A high satisfaction rating was provided by 82.2% of patients.

CONCLUSIONS

High survival and relatively few complication rates were observed for all prescribed FDPs over the observation period.

A simple, time-saving chairside device for radiographic diagnosis of vertical bone height and soft tissue thickness for implant placement--clinical report

A diagnostic radiograph of the posterior regions of the jaws is mandatory if implant placement is considered at these sites. The goal is to avoid damage to important anatomical structures such as the inferior alveolar canal and maxillary sinus. Using radiographs to evaluate the remaining bone height available for implant insertion is a common procedure. Many articles have evaluated the success rates of fixed prostheses supported by osseointegrated implants, indicating high rates of success for prostheses 5-10 years in function. However, if an orthopantomogram machine is not readily available, periapical radiographs can be used for vertical bone height assessment. The familiar procedure of incorporating a metal ball of known diameter into an acrylic template is the method of choice. This is a relatively tedious and expensive procedure involving multiple steps, including impression taking, creation of a study model, and manufacture of a metal ball-bearing acrylic template. A further disadvantage for the patient is that a diagnostic radiograph can be taken only at the next appointment. This paper describes a quick and simple method to obtain a radiographic evaluation of remaining alveolar bone height and soft tissue thickness prior to implant placement with help of a metal ball device to avoid template fabrication and time consumption. Soft tissue thickness is measured nonsurgically.

Accuracy of a newly developed open-source system for dental implant planning

PURPOSE

To evaluate the accuracy of a newly developed open-source system for three-dimensional dental implant planning and fully guided dental implant placement.

MATERIALS AND METHODS

Forty-eight implant positions were planned for eight partially edentulous anatomical patient equivalent models with an open-source implant planning system on the basis of cone beam computed tomography (CBCT) scans. The virtual software planning leads to an output of four different coordinates for each implant position; with these, surgical guides were manufactured using a coordinate-transfer apparatus. During the surgical simulation, drills and implants were fully guided as they were inserted by means of the harmonized components of the vendor's sleeve-in-sleeve system. After follow-up CBCT investigation and reference marker-based software registration, linear horizontal, vertical, and maximal 3D deviations, as well as angular deviations, between the virtual planning data and the surgical results were calculated.

RESULTS

The mean three-dimensional deviation values for the final implant positions were 671 μm (95% confidence interval [CI] 452 to 891 μm) at the implant base and 808 μm (95% CI 646 to 971 μm) at the implant tip. Mean vertical deviations were 273 μm (95% CI 200 to 345 μm). Mean angular deviations of 1.9 degrees (95% CI 1.4 to 2.4 degrees) were measured.

CONCLUSIONS

The open-source implant planning system described in this study demonstrated a level of accuracy that is equal or superior to most descriptions of the literature on computer-aided implant dentistry, allows for predictable implant positioning, and has the potential to reduce postoperative impairment versus conventional implant insertion.

Comparison of strains for splinted and nonsplinted screw-retained prostheses on short implants

PURPOSE

Because the evidence regarding the efficacy of splinting short implants on strain distribution is limited, this study aimed to measure and compare the strains generated by splinted and nonsplinted screw-retained implant crowns for short implants with internal connections.

MATERIAL AND METHODS

Computed tomographic scan data of a patient missing all mandibular molar teeth were digitized using a software program, and stereolithography was then used to produce an acrylic resin cast. Two 4- x 6-mm implants were placed in the left side. One set of splinted crowns and one set of nonsplinted crowns were made to fit the two implants using screw retention. Three-dimensional image correlation was used for full-field measurement of strains and provided a synchronized stereo view of the cast during the experiment. Cameras recorded changes in random dot patterns that had been applied to the surface of the cast as the prostheses were loaded up to 400 N in vertical and oblique directions using a universal testing machine. Testing was repeated three times for splinted and nonsplinted crowns. An image correlation algorithm used the dot pattern to define correlation areas. Coordinates of these areas were determined for each recorded photograph and used to calculate the strains. Strain distribution data were compared for maximum and minimum principal strains.

RESULTS

Qualitative data showed evidence of increased load sharing for splinted, screw-retained prostheses regardless of the direction of the load applied. However, the only statistically significant difference between the two prosthesis types occurred for peak maximum principal strain under oblique loading.

CONCLUSIONS

Splinting short implants may provide a more even strain distribution during functional loading. Clinical corroboration of these findings is needed.

Relationships between bone density values from cone beam computed tomography, maximum insertion torque, and resonance frequency analysis at implant placement: a pilot study

PURPOSE

The aim of the present study was to determine bone density in designated implant sites using cone beam computed tomography (CBCT) and to evaluate possible correlations between age, gender, insertion torque measurements, and resonance frequency analysis (RFA) values.

MATERIALS AND METHODS

Completely and partially edentulous patients were treated with implants between 2007 and 2008 and evaluated retrospectively. The preoperative examination included a panoramic radiograph, CBCT, diagnostic casts, and a clinical examination of the jaws. With the CBCT scans, bone densities were recorded in Hounsfield units (HU). Insertion torque values and implant stability measurements (via RFA) were also noted.

RESULTS

Mean bone density and insertion torque values were 623 ± 209 HU and 42.4 ± 4 Ncm, respectively, for the 82 implants placed. Mean primary stability (implant stability quotient) was 62.4 ± 8. The differences in mean bone density at implant sites in the mandible (717 ± 204 HU) and the maxilla (490 ± 128 HU) were statistically significant for all patients (P < .05). There was a statistically significant relationship between bone density values and insertion torque measurements for implant sites in the anterior mandible (r = 0.562, P < .05), as well as between bone density and RFA values for men (r = 0.412, P < .05).

CONCLUSIONS

Bone density measurements using preoperative CBCT may be helpful as an objective diagnostic tool. These values, in conjunction with RFA values and insertion torque measurements, can provide the implant surgeon with an objective assessment of bone quality and may be especially useful where poor-quality bone is suspected.

Reference-based digital concept to restore partially edentulous patients following an immediate loading protocol: a pilot study

PURPOSE

To describe the use of a computer-aided three-dimensional planning protocol in combination with previously placed reference elements and computer-aided design/computer-assisted manufacture (CAD/CAM) technology to restore the partially edentulous patient.

MATERIALS AND METHODS

Mini-implants and/or reference brackets were inserted or positioned in specified locations in a test cast and in two patients prior to imaging to act as definitive fiducial markers. This served as a fixed base to better define a setup for the fabrication of a surgical template used during computed tomographic imaging. A simulated partially edentulous maxilla was used for the study, and two partially edentulous patients participated. With the CT images, a CAD/CAM superstructure was created prior to surgery and inserted immediately after surgery. Fit of the prosthesis was assessed using three-dimensional tension measurements with strain gauges.

RESULTS

Mean misfit for all implants in the x-, y-, and z-axes was 26.6, 24.8, and 10.4 μm, respectively. The total misfit calculated according to the Pythagorean theorem was 42.6 μm.

CONCLUSIONS

Based upon this pilot study in two patients and an in vitro analysis, it appears that the use of reproducible fiducial markers consisting of mini-implants and reference brackets results in the fabrication of an acceptably accurately fitting definitive prosthesis prior to implant placement.

To immediately load, expose, or submerge in partial edentulism: a study of primary stability and treatment outcome

PURPOSE

This study was undertaken to assess the predictive usefulness of preoperative bone density, as measured by computed tomography (CT), and the intraoperative implant stability measures of insertion torque (IT), Periotest values (PTV), and resonance frequency analysis (ie, implant stability quotient [ISQ]) toward developing an algorithm for successful immediate loading, one-step exposure, or submergence of dental implants.

MATERIALS AND METHODS

Consecutively presenting patients requesting immediate loading in areas other than the anterior mandible were analyzed retrospectively. The implants were either immediately loaded, left exposed, or submerged on the basis of preoperative CT bone density and intraoperative primary stability measures. All implants surviving the traditional healing period were verified for osseointegration.

RESULTS

Eighteen patients were analyzed retrospectively, and they received 58 implants. Seven implants failed, for a survival rate of 88%. Primary stability measurements at insertion were correlated with one another and with preoperative CT bone density. Preoperative mean bone density for surviving implants was greatest for immediately loaded implants (983 ± 83), lower for exposed implants (803 ± 29), and lowest (480 ± 23) for submerged implants. Bone density was significantly different between submerged implants that failed and those that survived. Mean IT for successful implants was higher than for those that failed. Mean PTVs were lower (ie, better) for successful versus failed implants, although this difference was significant only for submerged implants.

CONCLUSIONS

In this group of patients, objective measures of bone density by CT, IT, PTV, and ISQ correlated with each other and therefore may provide a useful algorithm for making clinical implant loading decisions. Of the technologies applied in this group of patients, PTV was the most reliable predictor at implant placement of failure to osseointegrate.

Using cone beam computed tomography to determine safe regions for implant placement

This study sought to identify and follow the course of the incisive canal in the mental interforaminal region of the human mandible and to describe other anatomical landmarks present in this region. Cone beam computerized tomography (CBCT) studies for 40 patients were collected from the database at the Department of Oral & Maxillofacial Radiology, School of Dentistry, Lebanese University. Ten patients had edentulous mandibles; the other 30 had partially or completely dentate mandibles. Axial native images and panoramic and cross-sectional reconstructions were examined to assess the anatomical landmarks in the anterior mandible. Multiple neurovascular canals and foramina were clearly detected on CBCT studies of the mandible. Numerous foramina were seen on the internal surface of the mandible, even distant from the midline. The incisive canal was identified in 97.5% of the images. These anatomical landmarks should be evaluated carefully during preoperative planning.

Radiographic findings in the maxillary sinus: comparison of panoramic radiography with computed tomography

PURPOSE

To assess the prevalence of radiographic signs of maxillary sinus pathology in patients undergoing dental implant treatment and to compare the efficacy of panoramic radiography, computed tomography (CT), and three-dimensional (3D) CT with Implametric software in the diagnosis of sinus pathology.

MATERIALS AND METHODS

Thirty patients were selected at random from those being treatment-planned to receive implant-supported restorations in the maxilla and who had a panoramic radiograph, a conventional CT scan in acetate, and a 3D CT scan in digital format. The radiographic maxillary sinus findings were categorized as: (1) no sign of pathology, (2) mucosal thickening, (3) mucous cyst, or (4) occupation of the entire sinus.

RESULTS

Seventeen women and 13 men were included, with a mean age of 50.9 years. There was a 38.3% prevalence of radiographic abnormalities (23.3% mucosal thickenings, 10% mucous cysts, and 5% occupation of the entire sinus). Of the 23 sinuses that displayed radiographic signs of pathology, only 1 (4.3%) was correctly diagnosed by the panoramic radiograph.

CONCLUSIONS

The most common radiographic maxillary sinus finding was mucosal thickening, followed by mucous cysts and occupation of the whole sinus. Conventional CT can be considered a reliable method for the diagnosis of maxillary sinus pathology.

Simplifying fixed implant dental prosthetics

Through following the FPPD protocol for multiple adjacent implants, and delivering final abutments, picking up the metal framework, and delivering provisionals, many benefits are gained. The benefits of following the FPPD protocol are as follows: The restorative dentist is trying-in and delivering the final abutments in one visit as opposed to removing them and placing them multiple times. This requires less chair time and time for the patient. It also reduces the mechanical stress on the abutment screw and implant body due to the elimination of multiple try-in appointments. When the metal framework is tried-in and verified for fit, the restorative dentist has the opportunity check the retention, check the margins, and make any corrections that might be needed. The abutments will be staying in the mouth when the framework is picked up. This metal try-in allows for a verification of the bite to be given to the dental lab. The delivery of provisionals manufactured by the dental laboratory offers many advantages in the FPPD technique. The patient has a form of tooth much earlier in the traditional appointment sequence. The patient can now offer feedback to the doctor and laboratory for fabrication of the permanent prosthesis with regards to shape and color. The laboratory-fabricated provisionals offer progressive loading to the implants through having a reduced occlusion yet allowing food to stimulate the implants. Overall, the FPPD technique offers shorter appointment times, more rapid delivery of fixed supported teeth, improved doctor-technician communication, and less mechanical wear on the implant parts.

Comparison of ridge mapping and cone beam computed tomography for planning dental implant therapy

PURPOSE

The aim of this study was to compare the relative accuracy of the ridge-mapping method against that of standard computed tomography (CT).

MATERIALS AND METHODS

Consecutive partially edentulous subjects requiring dental implants were recruited for this prospective study. Vacuum-formed radiographic templates with reference points were used for the ridge-mapping procedure and CT scanning. Ridge-mapping measurements were translated onto study models, which were subjected to CT scanning with the templates in place. CT images of the study models obtained from the ridge-mapping method were compared with CT images of the subjects. The data were analyzed with the Wilcoxon signed-rank test. Differences were considered significant if P < .05.

RESULTS

Fourteen subjects were recruited and a total of 21 implant sites were evaluated. The ridge dimensions measured by the bone-mapping method and CT scanning were significantly different (P < .05). The mean difference ranged from 0.3 to 0.5 mm, and large variations were found in the sulcus region.

CONCLUSION

Measurements of the alveolar bone dimension using the ridge-mapping method are different from CT scanning, with a mean difference of about 0.4 mm.

A case series on crestal sinus elevation with rotary instruments

PURPOSE

This case series aimed to evaluate the clinical outcome of a crestal approach technique in sinus floor elevation surgery with insertion of an alloplastic material.

MATERIAL AND METHODS

A total of 50 edentulous patients received 64 implants and sinus floor elevation in posterior maxillae with residual crestal height 1.2 to 9.8 mm, and larger than 7 mm in width. Drilling perforation was performed until the sinus floor was felt. The sinus mucosa was then lifted. Hydroxyapatite granules were placed and implants were immediately inserted. Three months later, definitive crowns were cemented and patients were followed up for 18 months. Outcome measures were implant failures, complications and radiographic bone height gain measured 18 months after prosthetic loading.

RESULTS

No patient dropped out and all implants were successfully osseointegrated. Only minimal postoperative patient discomfort was reported. Only one complication occurred: a minor perforation of the sinus membrane with no negative consequences. At the time of implant insertion, the residual bone height mean value was 6.20 mm (±2.22). After surgery and at the last follow-up, the mean height of bone was 15.26 (±3.19) and 15.40 mm (±4.21), respectively.

CONCLUSION

The procedure was able to obtain sinus elevation and implant osseointegration.

Dental management in autosomal recessive (intermediate) osteopetrosis: a case report

Osteopetrosis (Albers-Schonberg disease) is the name given to a group of diseases that affect the growth and remodeling of bones. It is characterized by overgrowth and sclerosis of bone, resulting in thickening and narrowing of the marrow cavities throughout the skeleton. The exact cause is unknown, although failure of bone resorption related to defective osteoclasts is considered to be the basis of the problem. These patients present a significant challenge to the dentist for management of jaw and dental problems, as the disease process demands special strategies which are often at variance with conventional dentistry. The purpose of this paper was to report the management and follow-up of a child with intermediate autosomal recessive osteopetrosis who primarily complained of dental problems.

Morphologic classification and stress analysis of the mandibular bone in the premolar region for implant placement

PURPOSE

The objective of this study was to assess the influence of mandibular morphology on the stress and strain distributions in the bone supporting an implant.

MATERIALS AND METHODS

Subjects were selected from patients with missing mandibular premolar teeth. Computed tomographic scans of the premolar region were classified into nine groups based on the overall bone morphology and the relative position of the alveolar crest. Finite element models of the bone on the basis of this classification, with inserted implants and superstructures, were constructed. A load of 200 N applied 30 degrees buccal from the vertical axis was directed toward the occlusal surface.

RESULTS

One hundred two partially (n = 98) and completely (n = 4) edentulous subjects were recruited. Their ages ranged from 40 to 79 years (mean age, 60.5 years; 41 men and 61 women). Approximately 56% of the patients showed bone widening in the caudal direction. The maximum compressive stresses were shown in the lingual cervical regions. An influence of overall bone morphology on stress distribution was not observed; however, the alveolar crest contour clearly affected the maximum stress and strain values. Compressive microstrain above 4,000 was observed only when the alveolar crest was lingually located relative to the body of the mandible. These high strain levels were concentrated at the lingual cervical margin, with volumes ranging from 0.04 to 0.07 mm3.

CONCLUSION

The contour of the alveolar crest potentially plays a critical role in maintaining the bone levels surrounding implants.

Digital 3-D implant planning: Cerec meets Galileos

Prosthetically based implant planning is necessary so that implants are set expediently and correctly during surgery. A clinical case is presented to describe how this can be performed today purely digitally. Prosthetic planning was undertaken with the Cerec CAD/CAM system. The data record created was transferred and superimposed on a CBCT 3-D radiograph. The position of the implant was planned taking the prosthetic planning into account.

Alternative applications of guided surgery: precise outlining of the lateral window in antral sinus bone grafting

Computed tomography (CT) and the application of CT-based guided implant surgery allow clinicians to provide enhanced precision and accuracy in implant surgery. Because of the difficulty in transferring a patient's often complex anatomic sinus configurations, as viewed on a preoperative CT scan, into precise osteotomy cuts at antral bone graft surgery, a prototype cutting guide was developed. The surgical guide was developed through the use of CT imaging, SimPlant module Oral and Maxillofacial Surgery computer software (Materialise Dental, Glen Burnie, MD), and the stereolithographic process to precisely position the lateral window, facilitating Schneiderian membrane elevation. This report demonstrates the step-by-step method to perform precise guided sinus window preparation using computer software and a stereolithographically generated surgical guide.

[Study on noninvasive paraclinical evaluation methods according to particular aspects in patients diagnosed with partial dentition]

The aim of this study quantifies the contribution of the non invasive and minimally invasive methods of paraclinic evaluation corroborated with the clinical aspects, a particularly important element being represented by the inter-relation between the general condition--oral pathology.

MATERIAL AND METHOD

The study group was represented by patients with ages between 18 and 35 years, diagnosed with partial edentation, with various problems of the general condition. To the same extent, with concern to the study group a special emphasis was placed on the paraclinical results and the therapeutic trajectories directed by the use of the diagnodent, without ignoring the role the digital radiography has in the diagnostic stage as well as the therapeutic one.

RESULTS

The results obtained subsequent to the thermographic evaluation showed the initially hidden character of the general symptomatology, the patient being unaware of the presence of any pathology at the level of the apparatus and systems, factor which could have interfered negatively with the pathology specific to the field of dental medicine. Creating a hierarchy, the link offered by the thermogram between the systems and the dental segment is already known. The pathology under investigation, both at an oral level and at a general one pleads for the correlative aspects of the binomial dental unit--affected organ, the modifications of the thermographic trajectories for the somatic area analyzed after the specific therapy being eloquent.

Management of Dental Implant Fractures. A Case History

The widespread use of endosseous osseointegrated implants to replace missing natural teeth increases the chances of implant complications and failures, despite the high initial success rate reported in the literature. Implant fracture is one possible complication that results in ultimate failure of the dental implant. Such a complication poses a management crisis even for the most experienced clinician. This article reports on a case of implant fracture, its possible causes, and how the case was managed.