Comparison between flapless-guided and conventional surgery for implant placement: a 12-month randomized clinical trial

Objectives

The study was aimed at comparing implants installed with guided and conventional surgery.

Material and methods

Twenty-nine total edentulous patients were selected, and maxillary contralateral quadrants were randomly assigned to static computer-aided implant surgery (S-CAIS): flapless computer-guided surgery, and conventional surgery (CS): flap surgery with conventional planning. Tomography scans were performed at baseline and 10 days after the surgery for deviation measurement, and radiography was done at baseline and after 6 and 12 months, for peri-implant bone level (PIBL) analysis. Peri-implant fluid and subgingival biofilm were collected to evaluate bone markers and periodontal pathogens.

Results

S-CAIS showed less linear deviation at the apical point and the midpoint and less angular deviation (p < 0.05), with greater depth discrepancy in the positioning of the platform (p < 0.05). Higher values of vertical PIBL were observed for the S-CAIS group at baseline (p < 0.05), while lower values of horizontal PIBL were observed for CS (p < 0.05). Bone markers and Tf presented higher levels in CS (p < 0.05). Flapless S-CAIS allowed smaller linear and angular deviations than the conventional technique.

Conclusion

However, PIBL was higher in S-CAIS; the conventional technique led to a greater angiogenic and bone remodeling activity by elevating the angiogenic levels and bone markers.

Clinical relevance

Evaluating the different implant insertion techniques can guide clinical and surgical regarding the accuracy, the release pattern of bone markers, and the peri-implant bone level.

Trial registration

ReBEC-RBR-8556fzp.

     

A retrospective analysis of peri-implant tissue responses at immediate load/provisionalized microthreaded implants

PURPOSE: The aim of this retrospective study was to examine the peri-implant tissue status at immediately provisionalized anterior maxillary implants 12 to 30 months following tooth replacement. MATERIALS AND METHODS: This is a retrospective study of 43 microthreaded, TiO2 grit-blasted implants placed in healed ridges and immediate extraction sockets to restore maxillary anterior and premolar teeth in 28 patients. The cortical bone position relative to the implant reference point was evaluated at implant placement and 6 to 30 months following restoration. Radiographs were assessed using 7x magnification. The distance from the reference point to the cortical bone was measured to +/- 0.1 mm. The relationship of the peri-implant mucosa to the incisal edge of the definitive prosthesis was recorded. RESULTS: Four implants in 3 individuals failed during the first 6 weeks following placement and provisional loading. Cortical bone adaptation from the time of implant placement up to 30 months following restoration ranged from 0.0 mm to 1.5 mm (average, 0.33 +/- 0.40 mm mesially and 0.28 +/- 0.37 mm distally). The mean radiographic measurements from the interproximal crestal bone to the contact point were 4.53 +/- -0.91 mm (mesial) and 4.06 +/- 0.98. Maintenance and growth of papilla was observed in this group of immediate provisionalized single-tooth implants. Definitive abutment or abutment screw loosening was not observed. DISCUSSION: The linear clinical and radiographic measures of peri-implant tissue responses suggest that proper implant placement is followed by supracrestal biological width formation along the abutment and preservation of toothlike tissue contours. This may influence buccal peri-implant tissue dimensions. CONCLUSIONS: Generalized maintenance of crestal bone and the increased soft tissue dimension with maintenance of peri-implant papilla were identified as expected outcomes for immediate loading/provisionalization of microthreaded, TiO2 grit-blasted implants. Control of peri-implant tissues can be achieved to provide predictable and esthetic treatment for anterior tooth replacement using dental implants.     

Long-term cumulative survival and mechanical complications of single-tooth Ankylos Implants: focus on the abutment neck fractures

PURPOSE

To evaluate the cumulative survival rate (CSR) and mechanical complications of single-tooth Ankylos® implants.

MATERIALS AND METHODS

This was a retrospective clinical study that analyzed 450 single Ankylos® implants installed in 275 patients between December 2005 and December 2012. The main outcomes were survival results CSR and implant failure) and mechanical complications (screw loosening, fracture, and cumulative fracture rate [CFR]). The main outcomes were analyzed according to age, sex, implant length or diameter, bone graft, arch, and position.

RESULTS

The 8-year CSR was 96.9%. Thirteen (2.9%) implants failed because of early osseointegration failure in 3, marginal bone loss in 6, and abutment fracture in 4. Screw loosening occurred in 10 implants (2.2%), and 10 abutment fractures occurred. All abutment fractures were located in the neck, and concurrent screw fractures were observed. The CSR and rate of screw loosening did not differ significantly according to factors. The CFR was higher in middle-aged patients (5.3% vs 0.0% in younger and older patients); for teeth in a molar position (5.8% vs 0.0% for premolar or 1.1% for anterior position); and for larger-diameter implants (4.5% for 4.5 mm and 6.7% for 5.5 mm diameter vs 0.5% for 3.5 mm diameter) (all P<.05).

CONCLUSION

The Ankylos® implant is suitable for single-tooth restoration in Koreans. However, relatively frequent abutment fractures (2.2%) were observed and some fractures resulted in implant failures. Middle-aged patients, the molar position, and a large implant diameter were associated with a high incidence of abutment fracture.     

Clinical evaluation of non-surgical cleaning modalities on titanium dental implants during maintenance care: a 1-year follow-up on prosthodontic superstructures

Objectives

To investigate tissue health around implants with newly attached superstructures over 12 months of preventive maintenance appointments and instrumentation when necessary.

Material and methods

In a randomized, split-mouth study 32 implants (8 participants with 4 implants each) received followed-up care every 3 months after superstructure attachment. Implants and superstructures were randomly assigned to four treatment groups and treated if necessary: (1) titanium curettes (TC), (2) stainless steel ultrasonic tip (PS), (3) erythritol air-polishing powder (EP), or (4) rubber cup polishing (CON). Probing depths (PDs), bleeding on probing (BOP), modified gingival (mucosal) bleeding index (GBI) around implants, and full-mouth Plaque Control Record (PCR) were measured every 3 months. Clinical attachment levels (CALs) and height of keratinized mucosa (KM)/gingival margins (GMs) for implants/teeth and PD, BOP, and GBI for teeth were documented at baseline, 6 months, and 12 months. Matrix metalloproteinase 8 (MMP-8) and periopathogens were measured at baseline and 12 months.

Results

Participants exhibited minimal signs of periodontal inflammation with statistically significant PD improvement (3.0 ± 0.2 to 2.8 ± 0.3 mm; p = 0.022) and overall CAL (4.3 ± 0.8 to 4.0 ± 0.7 mm; p = 0.048) after 1 year. Implants showed no statistically significant differences (p > 0.05) between or within groups at baseline or 12 months for any parameter, except MMP-8 decreased significantly for PS (14.50 ± 17.58 to 4.63 ± 7.56 ng; p = 0.044), and after 12 months, PCR showed a significant difference between TC and PS (p = 0.018).

Conclusions

Treatment was necessary as inflammation was observed around newly placed superstructures within the first year of maintenance care. All tested treatment modalities yielded comparable clinical improvements.

Clinical relevance

Early assessment and diagnosis of mucositis and regular maintenance can promote long-lasting implant health.

     

Oral health-related impact profile in full-mouth restored patients with two different tooth-colored restoration materials

Objectives

To analyze the change of oral health impact profile (OHIP) in patients with full-mouth rehabilitations due to moderate/severe tooth wear dependent on different restorative materials (ceramic/experimental CAD/CAM composite).

Materials and methods

Twenty-nine healthy patients (15 male/14 female, age 44.6 ± 28.4 years) requiring full-mouth rehabilitation due to different degrees of tooth wear were instructed to fill the German version OHIP-G49 questionnaire before (baseline) and 30 days after prosthetic treatment with ceramic (n = 17) or experimental CAD/CAM composite (n = 12) restorations. Questions were divided into five dimensions: appearance, oral functions, psychosocial impact, linguistic limitations, and orofacial pain; changes between both OHIP-questionnaires for each question and patient were dissected by difference values, separately. Data were analyzed with the Kolmogorov–Smirnov, Wilcoxon’s signed-rank, Kruskal–Wallis, Mann–Whitney, and Cronbach’s alpha tests (significance level p = 0.01).

Results

The appearance dimension showed the highest results (p < 0.001, 100% improvement with all values > 0); the linguistic limitations dimension presented the lowest improvement (p < 0.001). The other three dimensions were not statistically different. No statistical differences between the two materials depending on OHIP questionnaire results occurred.

Conclusions

The esthetic appearance of the patients was influenced positively by full-mouth rehabilitation, irrespective of the material used. Improvements were also made in the parameters “toothache” and “problem of food intake.” No statements could be made for the parameter “language.”

Clinical relevance

With an increasing number of patients with moderate/severe tooth wear, thorough knowledge about the improvement of OHIP is important. This information is advantageous for the consultation and handling of patients when complex treatments are planned.

     

Morphological measurements of two separate mesiobuccal canals in maxillary first molars using micro-computed tomography

Objectives

To obtain radicular measurements of two separate mesiobuccal (MB) root canals in maxillary first molars using micro-computed tomography (μCT) with customized software.

Materials and methods

Human maxillary first molar MB roots (N = 36) with two separate canals (MB1, MB2) and apical foramina were scanned by μCT and analyzed with Kappa2 software to reconstruct three-dimensional (3D) surface models of roots and canals. These models were sectioned at 0.1 mm intervals perpendicular to the central axis of each canal. Canal widths, 3D curvatures, and surrounding dentine thicknesses were measured concurrently on each section. Dentine thicknesses were analyzed statistically for differences between each direction and the different levels of both canals.

Results

Dentine walls around MB1 were thicker than MB2 (p < 0.05). Thinnest dentine was most often located at disto-inside direction in both canals. Canal widths were significantly smaller in MB2 than MB1 (p < 0.01). Apical constrictions were smaller (p < 0.05) and further (p < 0.05) from the apex in MB2 than MB1. Canal curvatures were greatest in the apical third of both canals (p < 0.001), and they were greater in MB2 than MB1 (p < 0.05).

Conclusions

MB2 canals had shorter lengths, smaller widths, and more severe curvatures and were surrounded by thinner dentine walls. In MB2, apical constrictions were between 1 and 2 mm from the apex, compared to about 1 mm for MB1.

Clinical relevance

These detailed measurements and in-depth 3D analyses of maxillary first molar MB roots with two separate canals and apical foramina provide morphologic references for root canal therapy.

     

Implant survival or implant success? Evaluation of implant-based prosthetic rehabilitation in head and neck cancer patients—a prospective observational study

Objectives

Definition of implant success is unclear in prosthetic implant-based rehabilitation of head neck cancer patients.

Materials and methods

Fifty-two patients with 309 inserted implants were included in this prospective observational study. Implant survival (in situ and loaded) and implant success (modified Albrektsson criteria) at 2-year follow-up were evaluated under the influence of patient- and implant-specific variables.

Results

Thirty-nine patients with 234 implants finished the study. Overall implant survival after 2 years was 92.3% (216/234) with an osseointegration rate of 94% (220/234). Implant success was 78.6% (184/234). Main reasons for failure were “bone resorption > 1.7mm” (n = 27, 11.5%) and “implant not in situ or not loaded” (n = 18, 7.7%). Smoking (OR 3.1, p = 0.034), bone grafts (OR 2.4, p = 0.021) and radiation dose > 60 Gy (OR 3.8, p = 0.025) revealed as significant predictors for implant failure.

Conclusion

Implant survival differs significantly from implant success in head and neck cancer patients. Implant success is mainly determined by radiographic peri-implant bone resorption.

Clinical relevance

Dealing with head and neck cancer patients a higher amount of peri-implant bone resorption must be taken into account and warrants for intensified implant monitoring.

     

Clinical performance of short versus standard dental implants in vertically augmented bone: an overview of systematic reviews

Objective

To answer the question: What do we know so far about the clinical performance of short implants (≤ 7 mm) when compared to standard length implants in vertically augmented bone, as well as which is the overall confidence of the systematic reviews (SRs) about this topic?

Materials and methods

An overview of SRs was conducted. The searches were performed in six electronic databases and grey literature. SRs about short (≤ 7 mm) versus standard dental implants performance in vertically augmented bone were included. The assessed outcomes were marginal bone loss (MBL), implant survival (IS), prosthetic (PC) and biological complications (BC), costs, surgical time, and patient satisfaction. AMSTAR 2 was used to evaluate the overall confidence of included SRs.

Results

Thirteen SRs were included. Nine of twelve SRs reported a lower MBL for the short implant group. All the included SRs showed no difference in the IS between groups. A higher rate of BC was reported for standard-length implants in four out of five SRs. No differences regarding PC were reported in four of five SRs. Information related to patient preference, cost, and surgery time were underreported. The confidence evaluation of the SRs was stratified as low for five SRs and critically low for eight SRs.

Conclusions

In an overall low-to-very low confidence levels, short implants appear to perform better in the mid-term (up to 5 years) than standard dental implants associated with vertical bone augmentation regarding MBL and BC, but they have a similar performance regarding IS rates and PC. There is an imperative need to improve the methodological quality of SRs, and efforts should focus on conducting RCTs to broaden the knowledge on this topic.

Clinical relevance

Short implants could represent a viable, simpler, and less invasive treatment when available bone height is limited.

     

Spontaneous eruption of impacted maxillary incisors after surgical extraction of supernumerary teeth: a systematic review and meta-analysis

Objectives

To evaluate the spontaneous eruption potential of impacted human permanent teeth localized in the anterior part of the maxilla, after the surgical extraction of obstacles in their eruption pathway, by means of a systematic review and meta-analysis.

Materials and methods

A systematic literature search was carried out to locate studies reporting on the percentage of anterior permanent teeth erupting after surgical removal of the obstacle, without other interventions. Eruption potential of impacted teeth was calculated using a random-effects meta-analysis. Information about the sex proportion, follow-up duration, age and years during which the study was carried out was used for subgroup analyses.

Results

A total of twelve studies were included, with a total sample size of 960 cases and a follow-up period of up to 36 months. The results show that more than 65.5% of impacted teeth erupt spontaneously following surgical extraction of the obstacle, with an odds ratio of 4 (95% CI 1.9, 8.2) (p < 0.001) favouring spontaneous eruption.

Conclusions

When faced with an impacted maxillary anterior tooth, surgical extraction of the obstacle can lead to spontaneous eruption of the impacted tooth in the majority of cases, with better success with a longer follow-up for up to 3 years.

Clinical relevance

Based on the present meta-analysis, clinical recommendation would be to surgically remove the obstacle impeding the eruption of a maxillary anterior permanent tooth and wait for the eruption of the tooth for a period of 12–36 months, depending on the age of the patient.

     

The influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge. A 5‐year randomised clinical trial

This study aimed to compare the influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T_6 m), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar‐implant‐retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.     

Immediate placement and provisionalization of maxillary anterior single implants: 1-year prospective study

PURPOSE: This 1-year prospective study evaluated the implant success rate, peri-implant tissue response, and esthetic outcome of immediately placed and provisionalized maxillary anterior single implants. MATERIALS AND METHODS: Thirty-five patients (8 men, 27 women) with a mean age of 36.5 years (range 18 to 65) were included in this study. Thirty-five threaded, hydroxyapatite-coated implants were placed and provisionalized immediately after each failing tooth had been removed. The definitive restoration was placed 6 months later. The patients were evaluated clinically and radiographically at implant placement and at 3, 6, and 12 months after implant placement. RESULTS: At 12 months, all implants remained osseointegrated. The mean marginal bone change from the time of implant placement to 12 months was -0.26 +/- 0.40 mm mesially and -0.22 +/- 0.28 mm distally. No significant differences in the Plaque Index scores were noted at different time intervals. The mean midfacial gingival level and mesial and distal papilla level changes from pretreatment to 12 months were -0.55 +/- 0.53 mm, -0.53 +/- 0.39 mm, and -0.39 +/- 0.40 mm, respectively. All patients were very satisfied with the esthetic outcome and none had noticed any changes at the gingival level. DISCUSSION: Although marginal bone and gingival level changes were statistically significant from pretreatment to 12 months of follow-up, they were well within clinical expectations. CONCLUSION: The results of this study suggest that favorable implant success rates, peri-implant tissue responses, and esthetic outcomes can be achieved with immediately placed and provisionalized maxillary anterior single implants.     

Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs

Objectives

The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs.

Materials and methods

Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation.

Results

Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05).

Conclusion

Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects.

Clinical relevance

The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

     

Effect of implant macrogeometry on peri-implant healing outcomes: a randomized clinical trial

Objectives

This randomized split-mouth clinical trial investigated the influence of implant macrogeometry on bone properties and peri-implant health parameters during the healing process.

Material and methods

Ninety-nine implants were placed bilaterally in posterior mandibles of 23 patients that received at least four dental implant macrogeometries: standard geometry, Integra (IN) and three geometries inducing “healing chamber”: Duo (D), Compact (C), and Infra (IF). Insertion torque (IT) and implant stability quotient (ISQ) were measured. Peri-implant health were monitored by visible plaque index (VPI), peri-implant inflammation (PI), and presence of calculus (CC). Data were collected during 90 days. Data were assessed for normality using the asymmetry and kurtosis coefficients followed by the Shapiro-Wilk test. A one-way ANOVA was used to investigate differences in IT and linear bone dimensions between the macrogeometry groups. The repeated measurements ANOVA test or ANOVA-R was used for analysis of ISQ, VPI, and PI. Tukey-Kramer test or Student’s t test was used for comparisons between the groups or within each macrogeometry.

Results

Macrogeometry did not significantly influence IT and ISQ values. The minimum ISQ was recorded after 7 days (71.95 ± 12.04, p = 0.0001). Intermediate ISQ was found after 14 days, when the ISQ reached values that are statistically identical to primary stability. The VPI showed significantly higher scores for the D (0.88 ± 1.03) and IN (0.72 ± 0.94) implants after 7 days. The PI was only influenced by the healing time significantly decreasing from 7 (1.07 ± 0.89) to 21 days (0.18 ± 0.18).

Conclusion

Implant macrogeometry did not influence IT nor ISQ values. The relationship between IT and SS was more evident for the Duo implant, but only in the final stage of healing process.

Clinical relevance

Show to the clinician that the macrogeometry and drilling protocols did not interfere in the clinical behavior of the implants during the healing process. However, the IT, primary and secondary stability, is quite dependent of the surgeon experience.

     

Clinical performance of a glass ionomer restorative system: a 6-year evaluation

Objectives

The aim of this study is to evaluate the long-term clinical performance of a glass ionomer (GI) restorative system in the restoration of posterior teeth compared with a micro-filled hybrid posterior composite.

Materials and methods

A total of 140 (80 Cl1 and 60 Cl2) lesions in 59 patients were restored with a GI system (Equia) or a micro hybrid composite (Gradia Direct). Restorations were evaluated at baseline and yearly during 6 years according to the modified-USPHS criteria. Negative replicas at each recall were observed under SEM to evaluate surface characteristics. Data were analyzed with Cohcran’s Q and McNemar’s tests (p < 0.05).

Results

One hundred fifteen (70 Cl1 and 45 Cl2) restorations were evaluated in 47 patients with a recall rate of 79.6% at 6 years. Significant differences were found in marginal adaptation and marginal discoloration for both restorative materials for Cl1 and Cl2 restorations (p < 0.05). However, none of the materials were superior to the other (p > 0.05). A significant decrease in color match was observed in Equia restorations (p < 0.05). Only one Cl2 Equia restoration was missing at 3 years and another one at 4 years. No failures were observed at 5 and 6 years. Both materials exhibited clinically successful performance after 6 years. SEM evaluations were in accordance with the clinical findings.

Conclusions

Both materials showed a good clinical performance for the restoration of posterior teeth during the 6-year evaluation.

Clinical relevance

The clinical effectiveness of Equia and Gradia Direct Posterior was acceptable in Cl1 and Cl2 cavities subsequent to 6-year evaluation.

     

Short versus Standard Length Implants with Sinus Floor Elevation for the Atrophic Posterior Maxilla

Objectivesthe aim of this clinical study was to compare clinical and radiological outcomes of short dental implants inserted in pristine bone to standard length implants inserted in combination with sinus floor elevation.Materials and methodsFor this clinical study, the clinical and radiological outcome of 126 short dental implants (84 patients), inserted in pristine bone were compared with 312 standard length implants (156 patients), placed in combination with maxillary sinus floor elevation procedures.ResultsThe short implant group (test group [TG]; mean follow-up (± standard deviation (SD) 56.6 ± 42.9 months) and the augmented group (control group [CG]; mean follow-up 41.6 ± 37.6 months) showed cumulative survival rates of 91.8% and 92.4%. Cumulative 5-year implant survival rates were 91.8% for the TG and 90.7% for the CG (p=0.421). Mean marginal bone loss was significantly higher in the CG than in the TG, with a mean MBL of 0.70 ± 0.72 mm in the TG and 0.96 ± 0.91 mm in the CG (p<0.001). A comparable and promising oral health-related quality of life (OHRQoL) was observed in the control and test groups.ConclusionsAfter over 3 years, short implants placed in the resorbed posterior maxilla obtained similar results to standard implants combined with maxillary sinus floor augmentation procedures.     

Evaluation of immediately loaded mandibular four vertical versus tilted posterior implants supporting fixed detachable restorations without versus with posterior cantilevers

Background

Distally inclining posterior implants may be technically challenging in certain situations. The presence of a posterior cantilever can also exert unfavorable forces on supporting implants. The aim of the present study was to evaluate and compare peri-implant soft and hard tissues around 4 mandibular interforaminal implants having tilted posterior implants with posterior cantilevers, versus vertical implants, 2 in the interforaminal region and 2 in the first molar regions, without posterior cantilevers. All implants supported full-arch fixed detachable restorations opposing complete dentures.

Material and methods

A total of 80 implants were placed flapless in the mandibles of 20 edentulous participants. Four implants were placed for every participant, who were randomly assigned into 2 equal groups. Axial group implants were vertically aligned, with 2 implants in the interforaminal area and 2 in the molar area. Tilted group implants have 2 anterior axial and 2 posterior distally inclined implants. Interim screw-retained prostheses converted from pre-existing dentures were immediately fabricated and loaded on the same day of surgery. After awaiting period of 3 months, all participants received fixed detachable metal acrylic resin definitive restorations. A follow-up protocol of 3, 6, and 12 months was scheduled to assess the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, and marginal bone level and bone density changes.

Results

No statistically significant differences (P?>?.05) were found in the modified gingival index, modified plaque index, peri-implant probing depth, implant stability, bone density, and marginal bone level between the axial and tilted implant groups after the 1-year follow-up period.

Conclusion

Placing 4 flapless immediately loaded implants in mandibular edentulous patients that supported full-arch fixed restorations provided high implant and prosthodontic success rates whether posterior implants were tilted with posterior cantilevers or vertically aligned without posterior cantilevers.

Trial registration: Pan African Clinical Trial Registry database, PACTR201907776166846. Registered 3 July 2019, www.pactr.org.

     

The clinical effectiveness of implants placed immediately into fresh extraction sites of molar teeth

BACKGROUND: Studies concerning immediate implantation describe its use in the anterior and premolar regions. However, its clinical effectiveness in immediately replacing molar teeth has rarely been challenged. The purpose of this study was to evaluate the survival rate of implants placed immediately after extraction of molar teeth to support a fixed ceramo-metal prosthesis. METHODS: From 1989 to 1996, 56 immediate implants were placed in 43 patients following extraction of 51 molars; 46 molars were replaced by 1 implant and 5 molars replaced by 2 implants. All implants were restored with fixed prostheses (4 single crowns and 52 splinted). Mean follow-up period was 15 months (range, 4 to 60 months). The influence of the following parameters on implant failure was evaluated: gender, arch, smoking, pre-extraction vertical bone loss, implant length, and severity of complications between the two stages of surgery. RESULTS: The 5-year cumulative survival rate (5-year CSR) was 89%. The 5-year CSR among men was 84% compared to 93.5% among women. The maxillary 5-year CSR was 82% and the mandibular 92%. Among non-smokers (50 implants), the 5-year CSR was 90% compared to 83% among smokers (6 implants). Complications were evident in 8 (6 minor, 2 major) out of 50 non-failing implants compared to 2 (minor) of the 6 failing implants. No differences were evident in the other study variables. CONCLUSIONS: Immediate implantation in the molar region is an alternative, predictable surgical treatment. Immediate implantation in the posterior mandible has a better prognosis than in the posterior maxilla.     

Micro-CT evaluation of the cortical bone micro-architecture in the anterior and posterior maxilla and the maxillary sinus floor

Objectives

To perform a within-subject comparison of the cortical bone micro-architecture of the maxillary sinus floor (MSF) to that of the buccal aspect of the anterior and posterior maxilla.

Methods

Micro-CT scans of the buccal aspect of the anterior and posterior maxilla and of the MSF in 14 human anatomical specimens were recorded. Within-subject comparisons were performed for cortical thickness (Ct.Th) and porosity (Ct.Po), average pore volume (AvgPo.V), and pore density (Po.Dn).

Results

The MSF presented the lowest and the anterior maxilla the highest Ct.Th, while Ct.Po was significantly higher at the MSF compared to the posterior maxilla (p = 0.021). No relevant differences were recorded for AvgPo.V and Po.Dn among regions (p > 0.067). Further, an increased Ct.Th at the MSF was significantly associated with a lower Po.Dn, while a higher Ct.Th and an increased AvgPo.V in the anterior maxilla were associated with a higher Ct.Th and an increased AvgPo.V, respectively, in the posterior maxilla and MSF. Finally, within each region, the AvgPo.V was associated positively with Ct.Po and negatively with Po.Dn.

Conclusions

The cortical bone of the MSF is slightly less thick and slightly more porous compared to the cortical bone at the buccal aspect of the anterior and posterior maxilla.

Clinical relevance

During lateral and vertical bone augmentation procedures, the cortical recipient bone is perforated several times to open the bone marrow compartment to facilitate provision of osteoinductive cells and molecules in the augmented space. Whether it is meaningful to approach the MSF in a similar way during MSF augmentation procedures or whether the slightly more porous structure of the MSF observed herein reduces the cortical barrier function already sufficiently has to be assessed in future clinical trials.

     

Remineralization capacity of carious and non-carious white spot lesions: clinical evaluation using ICDAS and SS-OCT

Objectives

To assess the remineralization capacity of carious, non-carious, and combined white spot lesions (WSLs) using the ICDAS and SS-OCT.

Materials and methods

This clinical trial was based on a quasi-experimental design. Forty-two healthy subjects (median age 26.6 years), who visited university hospital and had at least one WSL with an ICDAS score of 2 or 1, were recruited. The subjects chewed a non-blind sugar-free gum containing bioavailable calcium and fluoride for 3 months. The remineralization capacities of carious and non-carious 121 WSLs were assessed using ICDAS by two calibrated non-blind examiners and optical boundary depth (BD) by SS-OCT at a monthly recall. The outcome variables, transitions of ICDAS score, mean BD, and mean BD recovery rate (RR%), were statistically analyzed using the chi-square test, two way-repeated measures ANOVA, and Wilcoxon rank sum test, respectively (alpha = 0.05).

Results

Based on the visual inspection, OCT images at the baseline, 72 WSLs were purely carious, 20 were non-carious (developmental) lesions, while 29 were combined (carious-developmental). The responses of WSLs over time showed to be highly variable. There was a significant difference in transitions of ICDAS scores after 3 months between carious and non-carious WSLs (p < 0.05) and non-carious and combined WSLs (p < 0.05). Carious and combined WSLs underwent significant changes in the mean BD between baseline (161.8 ± 56.8 μm) and 2 months (130.7 ± 57.4 μm) or 3 months (119.1 ± 57.5 μm) (p < 0.05), while there was no significant difference between baseline (132.2 ± 26.2 μm) and 2 months (122.8 ± 24.1 μm) or 3 months (119.8 ± 22.6 μm) in non-carious WSLs (p > 0.05). There was a significant difference in mean RR% after 2 and 3 months between carious and non-carious WSLs (p < 0.05).

Conclusions

The remineralization capacity of WSL was variable among the cases and subjects, and depended on the WSLs history, etiology (carious, non-carious, or combined lesion) and structure (histological pattern).

Clinical relevance

Carious WSLs showed the highest remineralization potential.

     

Maxillary buccal cortical plate inclination at mini-screw insertion sites

Objective:To evaluate whether buccal cortical bone inclination varies for the maxillary alveolar processes of adult patients with decreased, normal, and increased facial heights.Materials and Methods:Cone-beam computed tomography images of 135 adult patients, including 49 hypodivergent subjects (26 women, 23 men), 40 hyperdivergent subjects (24 women, 16 men), and 46 normodivergent (25 women, 21 men) were analyzed. Cortical bone inclination measurements were made relative to the occlusal plane. Cross-sectional slices of the maxilla were taken at interdental sites from the distal aspect of maxillary canine to the mesial aspect of maxillary second molar.Results:Analysis of variance indicated significant differences (P < .05) between the angles formed by the line tangent to the cortical bone and the occlusal plane among the vertical facial types for the regions between canine and first premolar and between second premolar and first molar at miniscrew insertion sites.Conclusion:The results of this study indicate that vertical facial pattern should be taken into consideration when adjusting the insertion angle of miniscrews at the maxillary buccal region.