The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial

Objectives: To evaluate the effect of maximum bite force (mBF) on marginal bone loss (MBL) around mini‐implants in edentulous patients wearing mandibular overdentures with two retention systems: ball and bar. Material and methods: Forty‐five totally edentulous patients were selected from a public health center. All of them received two mini‐implants (1.8 × 15 mm; Sendax^®) in the anterior mandible using a minimally invasive technique. A single randomization was performed to allocate the patients in two groups. Group I (n=22) received two single ball‐type mini‐implants and Group II (n=23) received two mini‐implants splinted with a prefabricated bar. The mBF was recorded using a press‐sensitive sheet Dental Prescale^® (Fuji) and MBL using standardized radiographs of each mini‐implant at the baseline and 5, 7, 10, and 15 months after surgery; the values were compared between groups. Results: Two members of Group I failed to complete the study, decreasing the number of participants to 20. There was no relationship between the mBF and the MBL of the mini‐implants (Spearman's ρr_s=0.147; P=0.378). At the 15‐month follow‐up, the average mBF for Group I (ball) was 247.53 ± 132.91 N and that of Group II (bar) only 203.23 ± 76.85 N (Mann–Whitney test; P=0.586). The MBL values were also higher for Group I (1.40 ± 1.02 mm) than Group II (0.84 ± 0.66 mm) during the entire 15‐month follow‐up period (Mann–Whitney test; P=0.077). Conclusions: No relationship was found between mBF and MBL for patients wearing overdentures retained on mini‐implants using bar or ball attachment systems. To cite this article:
Jofré J, Hamada T, Nishimura M, Klattenhoff C. The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial.
Clin. Oral Impl. Res. 21 , 2010; 243–249.
doi: 10.1111/j.1600‐0501.2009.01834.x     

Influence of marginal bone resorption on two mini implant-retained mandibular overdenture: An in vitro study

PURPOSETo investigate the biomechanical effect of marginal bone resorption (MBR) on the mandibular mini implant (MI)-retained overdenture (MI-OD) on the edentulous model.MATERIALS AND METHODSThe experimental mandibular edentulous model was modified from a commercial model with 2 mm thick artificial soft tissue under denture base. Two MIs (Φ2.6 mm × 10 mm) were bilaterally placed between the lateral incisor and the canine area and attached with magnetic attachments. Three groups were set up as follows: 1) alveolar bone around the MI without MBR (normal group), 2) with MBR to 1/2 the length of the implant (resorption group), and 3) complete denture (CD) without MI (CD group). Strain around the MI, pressure near the first molar area, and displacement of denture were simultaneously measured, loading up to 50 N under bilateral/unilateral loading. Statistical analysis was performed using independent-samples t test and one-way ANOVA (α=.05).RESULTSThe strain around the MI with MBR was approximately 1.5 times higher than that without MBR. The pressure in CD was higher than in MI-ODs (P <.05), while there was no statistical difference between the normal and resorption group (P >.05). Similarly, the CD demonstrated a greater displacement of the denture base than did the MI-ODs during bilateral and unilateral loadings (P <.05).CONCLUSIONThe strain around the MI with MBR was approximately 1.5 times higher than that without MBR. The pressure on posterior alveolar ridge and denture displacement of MI-ODs significantly decreased compared to CDs, even when MBR occurs. Bilateral balanced occlusion was recommended for MI-ODs, especially when MBR occurred.     

The effect of maximum bite force on alveolar bone morphology

Authors – Thongudomporn U, Chongsuvivatwong V, Geater AF Objectives – To investigate to what extent maximum bite force contributes to alveolar bone morphology parameters, i.e. alveolar thickness, shape and arch width. Design – An observational cross‐sectional survey. Setting and Sample Population – One hundred and fifty one 12‐ to 14‐year‐old students from a secondary school in Hatyai City, Songkhla Province, Thailand. Material and Methods – Height, weight and maximum bite force of each subject were recorded. Alveolar bone morphology parameters were measured from study models. Results – Maximum bite force moderately correlated with alveolar thickness and shape (r = 0.31–0.44, p < 0.001), but weakly correlated with arch width (r = 0.03–0.05, p > 0.05). After adjusting for gender and body mass index (BMI), the maximum bite force significantly determined alveolar thickness and shape (p < 0.001), accounting for 10–20% of the variations. Boys were associated with larger posterior arch width (p < 0.01), where BMI was not associated with alveolar bone morphology parameters (p > 0.01) after Bonferroni correction for multiple testing. Conclusion – Maximum bite force had a selective influence on alveolar thickness and shape, but not on arch width.     

Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study

The cover image is based on the Original Article Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study by Xiaoting Shen DDS et al., https://doi.org/10.1111/cid.13144 .

     

Retention and postinsertion maintenance of bar-clip, ball and magnet attachments in mandibular implant overdenture treatment: an in vivo comparison after 3 months of function

It could be hypothesised that attachments, which provide more retention against vertical and horizontal dislodgement, will be associated with more favourable parameters of oral function. This in vivo study is designed to provide data regarding initial retention force, loss of retention force after 3 months of function and postinsertion maintenance and complications associated with the use of magnet, bar-clip and ball attachments in mandibular overdenture treatment. Eighteen edentulous subjects received two permucosal implants in the inter-foramina region of the mandible, a new denture and three successive suprastructure modalities (magnet-, bar-clip and ball attachments). The retention force of the attachments at baseline and after 3 months was measured in a standardised way. The amount and type of postinsertion maintenance that was related to the attachment were evaluated. No differences in retention force at baseline and after 3 months of loading were observed for all three attachment types. The mean retention forces of magnet attachments, bar-clip attachments and ball attachments were 8.1, 31.3 and 29.7 N respectively. Functional maintenance complications related to the attachments were predominantly observed in 11/36 magnet attachments. Functional problems in the ball attachment group were relatively rare, easily manageable and seen in 4/36 attachments. The bar-clip attachments exhibited no maintenance problems at all.     

牙周维护对种植体周围边缘骨稳定性的影响

目的:探讨牙周维护对种植体周围边缘骨稳定性的影响.方法:选择上颌后牙缺失者,实验组为重度骨缺损10例,通过上颌窦底提升,同期植入种植体,种植前进行口腔卫生训练,修复后认真进行口腔卫生维护,定期复查,洁治;对照组为无骨缺损10例,种植修复后前3个月以患者日常方式进行口腔卫生维护,之后同实验组.修复后3、6、12个月分别检...     

3‐D in vivo force measurements on mandibular implants supporting overdentures. A comparative study.

Force transmission onto implants supporting overdentures was measured in viva by means of piezoelectric transducers that allow for simultaneous force registrations in 3 dimensions. The transducers are directly mounted onto the implants, beneath the anchorage device. The force registrations were analyzed with regard to the anchorage device and retention mechanism of overdenture support. The 3 types of denture anchorage were a U‐shaped bar, a round clip‐bar and single telescopes. Forces were measured in the following test situations: maximum force when biting in centric occlusion, maximum bite force during biting on a bite plate, grinding and chewing bread. Multiple regression showed that the vertical component of maximum forces was dependent on the anchorage device and test situation. The transverse components reached 10 to 50% of the vertical force magnitude. With the bite plate in situ maximum forces measured in vertical direction were significantly higher on the ipsilateral implant with telescopes than with bars ( p <0.01 and p <0.001). Chewing and grinding resulted in lower vertical forces compared to maximum biting. In transverse dimensions, mainly in the anterior‐posterior direction, registered forces reached magnitudes that resembled the vertical component (50 to 100%). Force magnitudes of chewing and grinding were similar for all three anchorage devices. However, differences were observed between bars and telescopes with regard to the direction of transverse force components. The results of this study do not suggest the preference of one specific anchorage system or retention mechanism for overdenture support. However, rigid bars contribute to load sharing and stress distribution onto the implants.     

The effect of denture stability on bite force and muscular effort

This study tested the hypothesis that denture instability limits the amount of voluntary muscular effort generated by denture wearers. Seventeen edentulous subjects (seven men, 10 women; mean age 60·3 ± 13·0 years) with newly acquired implant-retained mandibular overdentures and a conventional maxillary denture participated. Maximum bite forces and corresponding electromyographic (EMG) activity from the temporalis and masseter muscles (bilaterally) were recorded under two experimental conditions: (i) Unilateral premolar and molar bites without additional support, and (ii) premolar and molar bites with bite block support on the opposite side. In addition, EMG values alone were recorded during maximum clenching without any transducer between the upper and lower dentures. The level of muscular effort was significantly higher with greater denture support. These results indicate that denture instability probably prevents denture wearers from using the full potential of their jaw muscles, especially during unilateral biting and chewing, even with two implants supporting the mandibular dentures.     

Influence of alcohol and tobacco habits on peri-implant marginal bone loss: a prospective study

A prospective clinical study was conducted to explore the possible link between peri-implant bone loss and the widespread habits of tobacco smoking and alcohol consumption. One hundred and eighty-five patients who received 514 implants were followed up for 3 years. Peri-implant marginal bone loss was evaluated by digital panoramic radiography and image analysis techniques. Multivariate analysis showed that peri-implant marginal bone loss was significantly related to a daily consumption of >10 g of alcohol, tobacco use and increased plaque levels and gingival inflammation. The present results indicate that daily alcohol consumption and tobacco use may have a negative influence on predictable long-term implant treatment outcomes, producing peri-implant bone loss and compromising restorative treatment with implant-supported prostheses.     

Factors affecting late fixture loss and marginal bone loss around teeth and dental implants

Background: The predictability and high success rate of implant treatment have averted attention from factors affecting fixture loss and bone loss around implants. Purpose: The goal of this study was to retrospectively evaluate late fixture loss and marginal bone loss around implants that have been in function for 5 years and to relate these findings to bone loss in the natural dentition. Materials and Methods: One hundred and forty‐three consecutively treated patients who had received an implantanchored fixed prosthesis and completed a 5‐year follow‐up were selected. Intraoral and panoramic radiographs were used to assess bone loss. Results: The bone loss was greater around remaining implants in patients who had lost implants after loading. No correlation was found between bone loss around implants and that around teeth. Only 2% of the fixtures were lost during 5 years of functional load. Most fixture losses occurred in the edentulous maxilla. Seven of the nine patients who lost fixtures were smokers. Conclusion: These findings show that patients who lost implants also lost more bone around the remaining implants. There was no correlation between bone loss around implants and that around teeth, indicating that different interacting mechanisms are involved.     

种植体直径对下颌覆盖义齿植体边缘骨吸收影响的3年回顾性研究

目的 研究窄颈和常规颈种植体支持的下颌球帽覆盖义齿边缘骨吸收 (MBL)、机械并发症及患者满意度。方法覆盖义齿的设计方案为下颌无牙颌植入2枚种植体,上部附着体为非夹板式球帽结构。共分为2组：① 窄颈种植体(?=3.3 mm)为26例,52 枚种植体;② 常规颈种植体 (?=4.1 mm)为28例,54枚种植体。分别在佩戴覆盖义齿后的6个月、1年及3年,通过临床检查及影像学观察种植体周围软组织情况 (牙周袋深度、牙龈出血指数、菌斑指数及牙结石指数)、边缘性骨吸收（MBL）、修复并发症,并采用问卷调查患者满意度。结果 在3年的随访期内,108枚种植体均无松动脱落。窄颈和常规颈种植体组的平均MBL分别为（2.1±0.4）mm,（1.4±0.3）mm,两者差异具有统计学意义。窄颈和常规颈种植体组的维修频率分别为0.26、0.27次/（年?人）,患者满意度后者略高于前者,但上述两组数据无显著性差异。结论 3年的回顾性研究表明,在使用种植体支持下颌球帽覆盖义齿修复中,种植体的直径会对其边缘骨吸收产生一定影响。使用常规颈植体的边缘骨吸收少于窄颈植体,但两者机械并发症和患者满意度没有差异性。     

A rough surface implant neck with microthreads reduces the amount of marginal bone loss: a prospective clinical study

Objectives: An intra-individual controlled clinical trial was conducted to evaluate and compare the amount of marginal bone loss (MBL) found around implants of a comparable design, with or without retention grooves (microthreads) or polished necks, during the early stages of healing.
Materials and methods: Forty-eight (48) patients with missing mandibular posterior teeth were treated with two commercially available implants of the same brand (MIS): one with microthreads (S-model) and the other with a polished neck (L-model). MBL around each implant was measured on follow-up radiograms taken 4 months after placement (exposure and crown cementation), and 6 and 12 months after loading.
Results: Forty-six (46) patients completed the study, making 46 implant pairs available for statistical analysis. None of the implants failed to integrate. All the implants displayed some extent of bone loss throughout the follow-up period. At each time point (exposure, 6 and 12 months after loading), the S-model implants displayed statistically significant lower amounts of bone loss (0.22 vs. 0.76, 0.57 vs. 1.22 and 0.9 vs. 1.5 mm, respectively). Other than the type of the implant, no correlation was found between MBL and the implant stability values (PerioTest), dimensions, site of insertion or any of the other collected variables.
Conclusions: Implants with a roughened neck surface and microthreads are more resistant to MBL during the first phases of healing, as compared with implants with a polished neck.     

三种种植系统周边骨质吸收的对比研究

目的：用全景片评估平齐对接种植系统、平台转换种植系统边缘骨吸收的差别。方法：植入平齐对接种植体（Noble Replace）54枚,小平台转换种植体（Osstem GS）14枚,斜肩式平台转换种植体（Bicon）25枚。在种植体植入当天、负载3个月后分别进行全景片检查,测量种植体边缘牙槽骨高度,计算牙槽骨丧失量。SPSS14．0软件进行统计分析。结果：功能负载3个月后,平齐对接种植体近、远中边缘骨吸收量分别为1．88mm±1．49mm、1．81mm±1．34mm;斜肩式平台转换种植体为-0．68mm±0．99mm、-1．17mm±1．37mm;小平台转换种植体为0．53mm±1．48mm、0．74mm±0．99mm。三种种植体两两比较,P〈0．05,相互之间存在显著性差异。结论：应用平台转换技术可减少种植体边缘骨吸收,不同的平台转换设计,其保存种植体周围骨质的能力明显不同。