Purpose: This study aimed to investigate the effect of attachment type, maximum occlusal force, denture deformation, and other confounding factors on marginal bone loss of two-implant overdentures after 1 year.

Materials and Methods: Ninety edentulous patients received two implants in canine areas of the mandible using the computer-guided flapless surgical technique. Three months later, overdentures were connected to the implants with bar, resilient telescopic, and resilient stud attachments. Marginal bone loss was evaluated using standardized digitized periapical radiographs. Maximum occlusal forces were evaluated using a digital bite-force meter. Denture base deformation (denture strains, μm) was evaluated using strain gauges bonded to the polished surface of the denture at the level of the attachments. Regression analysis was adopted to find the relation between marginal bone loss and the following confounders (age, sex, mandibular bone height, period of edentulism, number of previous dentures, attachment type, maximum occlusal force, and denture strains).

Results and Conclusion: Telescopic overdentures showed the highest marginal bone loss and maximum occlusal force, followed by bar overdentures, and stud overdentures demonstrated the lowest values. The highest denture strains were noted with bar overdentures, followed by telescopic overdentures, and stud overdentures showed the lowest strains. Age (P = .022), mandibular bone height (P = .023), number of previous dentures (P = .004), maximum occlusal force (P ≤ .001), and denture strains (P = .048) were significantly correlated with marginal bone loss. For every 1-year increase in age, there was a decrease in bone loss by 0.3%. For every 1-mm increase in bone height, there was an increase in bone loss by 1%. For every one increase in the number of worn dentures, there was a decrease in bone loss by 4.2%. For every 10-N increase in maximum occlusal force, there was an increase in bone loss by 6.4%. For every 10-μm increase in denture strains, there was an increase in bone loss by 0.21%. Sex, time of edentulism, and attachment type did not demonstrate a significant correlation with marginal bone loss. Int J Oral Maxillofac Implants 2022;37:391–399. doi: 10.11607/jomi.8982

ABSTRACT

Purpose of the study: The aim of the present study was to investigate the marginal bone height changes around maxillary and mandibular implants supporting all on four fixed detachable prosthesis after one year follow up

Materials and methods: six completely edentulous patients (4 males and 2 females) received new conventional maxillary and mandibular dentures and were asked to wear them for 3 months to enhance adaptation. Four implants were inserted in the maxillary (between the nasal sinuses) and mandibular (between the mental foramina) arch of each patient according to the All On four protocol. Implants were immediately loaded with provisional dentures after connection of multiunit abutments, and after 3 months of osseointegration temporary dentures were replaced by fixed ceramo-metal prosthesis. Vertical marginal bone loss (VBL) was evaluated at the time of fixed hybrid prosthesis insertion, 6 and 12 months later using standardized peri-apical radiographs.

Results: Maxillary anterior implants recorded significant higher VBL (P ≤ 0.005) than mandibular implants after 6 months and 12 months of prosthesis insertion. Also, the maxillary anterior implants showed significant VBL (P ≤ 0.005) than the posterior implants. For the posterior implants, no significant difference in VBL was observed between the maxillary and mandibular implants. For the mandibular implants, no significant difference in VBL between the anterior and posterior implants was observed.

Conclusion: Within the limitation of this short-term study, taking the small patient cohort into account, it could be concluded that maxillary anterior implants supporting all on four fixed hybrid prosthesis are at increased risk for marginal bone loss compared to maxillary posterior implants or mandibular implants.

ABSTRACT

Purpose: The aim of this cross over study was evaluation of patient satisfaction and oral health related quality of life (OHRQoL) for implant supported mandibular overdentures with locator attachments in patients with resorbed ridges

Materials and methods: Six participants (3 males and 3 females) with total maxillary and mandibular edentulism who complained from lack of retention of old mandibular dentures due to ridge resorption received new conventional dentures. After 3 months adaptation period, 4 implants were inserted between the 2 mental foramina of the mandible using one stage non submerged delayed loading approach. After 3 months of integration period, dentures were connected to the implants with Locator attachments. Patient satisfaction was measured using patient satisfaction questionnaires and oral health related quality of life was measured using oral health impact profile (OHIP-14). Measurements were made after 3 months of using conventional dentures (control group) and implant overdentures (study group).

Results: Regarding VAS questionnaires, test group showed significant higher general satisfaction, satisfaction compared to natural teeth, satisfaction with retention, stability, occlusion, speech, mastication, prosthesis is a part of patient, and lack of embarrassment compared to control group. Regarding OHIP-14, test group showed significant less pain and more comfort on eating, less self-consciousness, and less sensation of tense, more satisfaction with food and less interruption of meal, more ability to relax and less embarrassing, less irritation with other and more satisfaction with life generally and less difficulty in function well than control group

Conclusion: Implant supported mandibular overdentures with locator attachments are recommended for patients with atrophied mandibular ridges as they significantly improve patient satisfaction and quality of life compared to conventional dentures.

ABSTRACT

Purpose: to investigate outcomes of Poly ether-ether ketone veneered with composite and porcelain fused to metal Full arch fixed screw retained prosthesis for patients with atrophied mandibular ridges.

Material and methods: Eight (4 men and 4 women) edentulous patients complaining from mandibular ridge atrophy were randomly assigned into 2 groups; Group I included 4 patients who received 8 implants and porcelain fused to metal full arch fixed restoration, Group II included 4 patients who received 8 implants and Poly ether-ether (PEEK) fixed restoration veneered with composite resin teeth. All implants were inserted using computer guided flapless surgical approach and loaded by definitive restorations after 3 months of osseointegration. Clinical (plaque and gingival index, probing depth, implant stability) and radiographical (bone resorption using cone beam CT) evaluations were performed at time of prosthesis insertion, after 6 month and one year thereafter.

Results: The survival was 90.7% and 100% in group I and group II respectively. Plaque and gingival indices increased with time in metal group only and PEEK group showed significant lower plaque and gingival indices than metal group after 6 and 12 months. Probing depth and bone resorption showed an increase values with passage of time in both groups and PEEK group showed significant lower probing depths and bone losses than metal group. Implant stability did not differ between groups or observation times was noted

Conclusion: Within limitations short term randomized trial, it could be concluded that Poly ether-ether ketone veneered with composite full arch fixed screw retained prosthesis is advantageous than porcelain/metal restoration for patients with atrophied mandibular ridges as it showed favourable per-implant tissue health after one 12 months.

ABSTRACT

Aim: This within-subject study report to investigate masticatory efficiency and maximum bite force of Locator and telescopic crown attachments used to retain maxillary implant overdentures.

Materials and methods: Six edentulous patients (3 males and 3 females) received 4 implants in the anterior maxillary region between the maxillary sinuses using a standardized 2 stage surgical approach. Six months after osseointegration, the implants were loaded either by Locator or telescopic maxillary overdentures in a cross-over study design. Masticatory efficiency was performed using the 2-colored gum mixing ability test. The gum was chewed for 5, 10, 20, 30, and 50 cycles, and the images of the chewed gum were analyzed using a Photoshop program to calculate the unmixed fraction (UF). Also, maximum bite force was evaluated using a bite-force transducer. Chewing efficiency and maximum bite forces were evaluated 3 months after wearing each overdenture.

Results: The success rate was 100% in both groups. There was a trend for a decrease in UF (ie improved masticatory efficiency) with the increase in the number of masticatory cycles. Telescopic maxillary overdentures showed significantly lower UF (ie higher masticatory efficiency) and higher maximum bite force than Locator maxillary overdentures

Conclusion: Telescopic attachments are recommended for maxillary implant overdentures as it had improved masticatory efficiency and maximum bite force than Locator attachments

ABSTRACT

Purpose: The aim of this randomized clinical trial was to evaluate biologic and prosthetic complications with two versus four mini-implants supporting mandibular overdentures in patients with knife edge ridges. Materials and methods: Twelve edentulous participants (6 men and 6 women, mean age =58.47 years) were randomly assigned into 2 groups; Group 1(control); included six participants who received four mini dental implants equally distributed in the interforaminal area of the mandible. Group 2 (study); included six participants who received two mini dental implants the canine area of the mandible. For both groups mandibular dentures were connected to the implants by O-ring attachments. The incidence biologic and prosthetic complications (related to the implants/ attachments and to the overdentures) were measured from base line 12 months after overdenture insertion and compared between groups.

Results: The implant survival rate, peri-implantitis, pocket depth >3mm, bone loss >1mm, separation of the metal housing from the denture base, teeth fracture, overdenture fracture, and denture relinings did not significantly differ between groups. The 4-implant group showed significant higher pain, edema, peri-implant mucositis, teeth wear, and denture border adjustments than the two implant group. The 2-implant group showed significant higher abutment bending / fracture, O/ring wear/ distortion, and O/ring damage/replacement than the 4-implant group

Conclusion: Within the limits of this short term trial, 2 mini-implants may be a suitable alternative to 4-mini-implants when used to retain mandibular overdentures as it was associated with reduced pain, edema, peri-implant mucositis, teeth wear, and denture border adjustments. However, 2-mini-implants are associated with increased prosthetic complications related to attachments as abutment bending /fracture, O/ring wear/ distortion, and O/ring damage/replacement.

ABSTRACT

Purpose: This study aimed to evaluate Peri-implant strain with locator and bar attachment during dislodging of maxillary implant overdenture Materials and methods: Four implants were inserted in completely edentulous acrylic maxillary model in canine and premolar areas. Experimental maxillary overdentures with 4 metal hooks were constructed and connected the implants with bar attachments (group I) or locator attachment (group 2). Two strain gauges were bonded at buccal and palatal surface of each implant. Micro strains were measured at buccal and palatal surface of canine and premolar implants during the vertical dislodging of the overdenture. Dislodging was made by chains connected at one end to the metal hooks and to a universal testing machine at the other end.

Results: For canine and premolar implants, locator attachment showed significant higher microstrain values than bar attachments at buccal and palatal gauge positions. For bar group, no difference between buccal and palatal strain gauge positions was detected. However, for locator attachments, buccal strain gauges demonstrated significant higher strain than palatal gauges. For buccal and palatal strain gauges, canine implants showed higher strains than premolar implants for both groups

Conclusion: Within the limitation of this in vitro study, could be concluded that bar attachments may be recommended to retain maxillary implant overdentures than locator attachments in terms of reduced peri-implant stresses that occur during the denture dislodgment which may lead to increased bone resorption around the implants.

Abstract

The aim of this study was to compare implant failure and radiographic bone level changes with different loading protocols for unsplinted two-implant-supported mandibular overdentures. An electronic search of two databases (PubMed, Cochrane Library) was performed, without language restriction, to identify randomized controlled trials (RCTs) comparing immediate or early versus conventional dental implant loading protocols for unsplinted two-implant-supported mandibular overdentures. Data were extracted independently by two reviewers. The Cochrane tool was used to assess the quality of included studies. A meta-analysis was performed. Eight RCTs were identified, seven of which were included; one trial was excluded because related outcomes were not measured. Four of the seven studies were considered to have a high risk of bias and three an unclear risk. Meta-analysis revealed no difference between immediate versus conventional or early versus conventional implant loading protocols regarding implant failure (risk difference (RD) −0.02, 95% confidence interval (CI) −0.13 to 0.10; RD 0.09, 95% CI −0.03 to 0.20) or marginal bone loss (mean difference (MD) 0.09, 95% CI −0.10 to 0.28; MD −0.05, 95% CI −0.12 to 0.02) for implants supporting mandibular overdentures. These findings should be interpreted with great caution given the serious numerical limitations of the studies included.

Objective the purpose of this study was to evaluate the push-out bond strength of ready-made glass fiber post and custom-made e-max pressable post treated with various surface treatments: Sandblasting (SB), Sandblasting in conjunction with silica particles then silane coating (SC) and Etching using hydrofluoric acid then silane coating (E)

Materials and methods: Forty freshly extracted single rooted upper central incisor teeth were selected. All root canals were endodontic treatment according to standard procedure then divided into two main groups (20 samples each) according to the type of posts were used. The first group (G) was restored with ready-made glass fiber post (Glassix plus radiopaque) (n=20), The second group (P) was restored with custom made pressable ceramic (E-max press post) (n=20) (Ivoclar Vivadent).Each group was subdivided to four subgroups (5 samples each) according to the type of surface treatment done: subgroup C: no surface treatment (control), Subgroup SB: sandblasting with 50 µm Aluminum-oxide (AL2 O3 ) particles, subgroup SC: sandblasting in conjunction with silica coating particles then silane coating and subgroup E: etching with 9.5% hydrofluoric acid then silane coupling agent. All samples were sectioned by IsoMet into 3sections (2mm each thickness) from coronal to apical then subjected to push-out test by universal test machine. Then all data were calculated, tabulated, and statistically analyzed.

Result: readymade glass fiber post show higher bond strength than custom made e-max press post with no significance different between them

Conclusion: Silica coating then silanization of ceramic e-max post is the best surface treatment that increase bond strength .Etching with hydrofluoric acid then silanization of glass fiber post is the best surface treatment that increase bond strength. Bond strength of glass fiber post was higher than bond strength of ceramic emax post

The purpose of this study was to investigate fracture strength of different lithium disilicate occlusal veneers designs with different tooth preparations.

Material and method: Fifty-six extracted human mandibular molars were collected with relatively comparable size and standardization done by diamond saw and it will receive. 6mm lithium disilicate occlusal veneers. Specimens will be divided into two main groups, each of these groups contains 28 samples (group A&B), the first group represents occlusal veneers with 1.0 ml with radial shoulder finish line design includes axial surfaces for a2 ml length, while the second group represents occlusal veneers preparation without finish line. Each main group will be subdivided into 2 subtypes groups (A1, A2, B1, B2), each subtype group contains 14 samples, the first subtype group will receive a buccal groove, while the second subgroup will be without grooves. Each subgroup will be divided into 2 classes (7 samples) according to the type of test it will be subjected to: microleakage, bond strength.

Results: The fracture strength is (mean value+ standard deviation) in plain occlusal reduction without vs with buccal groove (890.36 [+ or -] 42.51N), (865.69 [+ or -] 36.79N). The fracture strength is (mean value [+ or -] standard deviation) in occlusal reduction with radial shoulder, without or with buccal groove (835.36 [+ or -] 42.51N), (820.69 [+ or -] 36.79N), with non-significant difference p value 0.05.

Conclusions: All tested occlusal veneer designs proved to withstand normal and parafunctional masticatory forces with non-significant statistical difference.