Ultrasound insonation angle and scanning imaging modes for imaging dental implant structures: A benchtop study.

INTRODUCTION: High frequency ultrasound has shown as a promising imaging modality to evaluate peri-implant tissues. It is not known if the ultrasound imaging settings might influence ultrasound's ability to differentiate implant structures. The aim of this benchtop study was to evaluate the dependence of ultrasound on imaging angles and modes to measure implant geometry-related parameters. METHODS: A clinical ultrasound scanner (ZS3, Mindray) with an intraoral probe (L30-8) offering combinations of harmonic and compound imaging modes was employed for imaging 16 abutments and 4 implants. The samples were mounted to a micro-positioning system in a water tank, which allowed a range of -30 to 30-degree imaging angles in 5-degree increment between the probe and samples. The abutment angle, implant thread pitch and depth were measured on ultrasound, compared to the reference readings. The errors were computed as a function of the image angles and modes. All samples were replicated 3 times for 3 image modes and 11 image angles, thus resulting in 2,340 images. RESULTS: The mean errors of ultrasound to estimate 16 abutment angles, compared to the reference values, were between -1.8 to 2.7 degrees. The root mean squared error (RMSE) ranged from 1.5 to 4.6 degrees. Ultrasound significantly overestimated the thread pitch by 26.1 µm to 36.2 µm. The error in thread depth measurements were in a range of -50.5 µm to 39.6 µm, respectively. The RMSE of thread pitch and depth of the tested 4 implants was in a range of 34.7 to 56.9 µm and 51.0 to 101.8 µm, respectively. In most samples, these errors were independent of the image angle and modes. CONCLUSIONS: Within the limitations of this study, high-frequency ultrasound was feasible in imaging abutments and implant fixtures independent of scanning angle within ±30° of normal incidence and for compounding and non-compounding-based imaging modes.

Immediate Implant With Provisionalization and Soft Tissue Grafting After 4-Year Follow-Up.

INTRODUCTION: This paper presents a case report of immediate implant placement (IIP) with a provisionalization technique to restore function and esthetics with follow-up after 4 years. CASE PRESENTATION: Minimally traumatic extraction was performed with IIP, soft-tissue grafting, and immediate provisional crown. Six months after optimal healing, the patient was submitted to an esthetic restorative work through veneers in lithium disilicate. Fourteen-month and 4-year follow-up visits revealed stability of the peri-implant soft-tissues with peri-implant health status, with the evaluation of the pink and white esthetic score, yielding to mean scores, respectively, in 14 months of 11.62 ± 2.07 (pink esthetic score [PES]) and 18.25 ± 1.46 (PES/white esthetic score [WES]) and in 4 years of 11.0 ± 1.32 (PES) and 17.62 ± 0.65 (PES/WES). Intraoral digital radiographs showed minimal crestal bone level changes throughout the follow-up period. Thus, IIP is a sensitive technique procedure, and a 3D implant position is crucial for success. CONCLUSION: Immediate implant with grafting to fill the gap and soft tissue augmentation led to less horizontal changes and stable mucosal margin, and immediate provisionalization helped to maintain soft tissue architecture, and proper case selection is key for clinical success.

Effect of different implant placement depths on crestal bone levels and soft tissue behavior: A 5-year randomized clinical trial.

OBJECTIVES: This randomized clinical trial analyzed the long-term (5-year) crestal bone changes and soft tissue dimensions surrounding implants with an internal tapered connection placed in the anterior mandibular region at different depths (equi- and subcrestal). MATERIALS AND METHODS: Eleven edentulous patients were randomly divided in a split-mouth design: 28 equicrestal implants (G1) and 27 subcrestal (1-3 mm) implants (G2). Five implants were placed per patient. All implants were immediately loaded. Standardized intraoral radiographs were used to evaluate crestal bone (CB) changes. Patients were assessed immediately, 4, 8, and 60 months after implant placement. The correlation between vertical mucosal thickness (VMT) and soft tissue recession was analyzed. Sub-group analysis was also performed to evaluate the correlation between VMT and CB loss. Rank-based ANOVA was used for comparison between groups (α = .05). RESULTS: Fifty-five implants (G1 = 28 and G2 = 27) were assessed. Implant and prosthetic survival rate were 100%. Subcrestal positioning resulted in less CB loss (-0.80 mm) when compared to equicrestal position (-0.99 mm), although the difference was not statistically significant (p > .05). Significant CB loss was found within the G1 and G2 groups at two different measurement times (T4 and T60) (p < .05). Implant placement depths and VMT had no effect on soft tissue recession (p > .05). CONCLUSIONS: There was no statistically significant difference in CB changes between subcrestal and equicrestal implant positioning; however, subcrestal position resulted in higher bone levels. Neither mucosal recession nor vertical mucosa thickness was influenced by different implant placement depths.

Using Digital Technique to Obtain the Ideal Soft Tissue Contour in Immediate Implants With Provisionalization.

This paper presents a newly developed digital technique to make a provisional crown that mimics the natural tooth during immediate implant placement. Basically, a digital technique results in a precise transfer tooth emergence profile for provisional restoration in immediate implant placement so that an ideal periimplant soft tissue contour can be maintained. The architecture of extraction socket is obtained digitally before the surgery that allows for implant planning by position of the implant as well as the emergence profile of provisional restoration. The introduction of this approach provides a versatile, precise, and predictable procedure leading to better esthetic outcomes.

Factors Influencing the Presence of Papilla between Adjacent Implants and between a Tooth and an Implant.

AIM: The aim this study was to evaluate the factors that influence the presence or absence of the interproximal papilla between implants adjacent to the teeth or other implants, through clinical and radiographic evaluation. MATERIAL AND METHODS: The non-probabilistic sample comprised 44 patients of both genders aged between 21 and 68 years, rehabilitated with 114 osseointegrated implants. Through a retrospective clinical study, the patients were divided according to the presence or absence of the interproximal papilla: Group 1 - Absence of Papilla, Group 2 - Partial Presence of Papilla and Group 3 - Total Presence of Papilla. The success of the implants, the periodontal biotype, and the vertical and horizontal distances of the interproximal regions included in the study were evaluated. RESULTS: Of the 114 implants, 46.5% were considered unsuccessful, and bleeding was present in 29.8%. The periodontal biotype presented as thin and scalloped was found in 85.1% of the regions. The evaluation of the groups according to the confirmation of the interproximal space showed a statistically significant difference (p = 0.007), with 61.9% of the wide and long interproximal spaces classified as Group 1, while 31% of the narrow and short interproximal spaces were classified as Group 3. CONCLUSION: It was concluded that the morphology of the interproximal space was the factor that was most strongly associated with the presence or absence of the interproximal papilla.

Effect of different implant placement depths on crestal bone levels and soft tissue behavior: a randomized clinical trial.

OBJECTIVES: This randomized clinical trial analyzed crestal bone changes and soft tissue dimensions surrounding implants with an internal tapered connection placed in the mandible anterior region at different depths (equicrestal and subcrestal). MATERIALS AND METHODS: Eleven edentulous patients (five implants per patient) were randomly divided in a split-mouth design: G1, 28 equicrestal implants; and G2, 27 subcrestal implants. All implants were immediately loaded. Correlation between keratinized tissue width (KTW) and vertical mucosa thickness (MT) with soft tissue recession was analyzed. Intraoral radiographs were used to evaluate crestal bone changes. Patients were assessed immediately, 4-, and 8-months after implant placement. Rank-based ANOVA-type statistical test was used for comparison between groups (α = 0.05). RESULTS: Fifty-five implants (G1 = 28 and G2 = 27) were assessed in 11 patients. Implant survival rate was 100% for both groups. Both tested implant placement depths presented similar crestal bone loss (P > 0.05). Significant crestal bone loss for each group was found in the different measurement times (T4 and T8) (P < 0.05). Implant placement depths, KTW, and vertical MT had no effect on soft tissue recession (P > 0.05). CONCLUSIONS: Different implant placement depths do not influence crestal bone changes. Soft tissue behavior is not influenced by different implant placement depths or by the amount of keratinized tissue.